Is Using 20W-50 Oil Good For Your Motor?

[GotToyota?]

Hey Jdub, sorry to bug you about this but...

The new car I'm getting on Saturday is confusing me, oil wise. The owner tells me he was running Mobil 1 20W-50, and after questioning the local Supra shop guy, he says a #W-50 is recommended in the owners manual. I was doubting this, but I don't have a owners manual right now to confirm. He was saying that because of the fact that many people don't run this oil, could be the very reason why so many people get rod knock. I'm not agreeing with him here, I would just like your feedback concerning this.

-Matt

 

[jdub]

Matt - Well you just got to experience first hand why a lot of people think a thicker oil is best. I can assure you it is not...not using a 20W-50 has no impact on developing rod knock. This guy is basically talking out of his arse

People will point at the Supra manual oil chart and tell you a 20W-50 is recommended. It is one of the oils listed, but they don't tell you it's just ONE option available. Take a look at the chart:



Note that 20W-50 is listed for a 10 to 100+ F temp range...so is a 15W-40 and 20W-40. On the 2nd line a 10W-30, 10W-40, and 10W-50 are listed for 0 to 100+ F temps...a wider temperature range. Also, if you look at the verbiage at the top, the manual shows API grades SF, SF/CC, and SG...all are obsolete API grades...you cannot even buy these oils anymore. The current API grades are SL and SM...these oils represent a quantum leap in formulation improvements over the oils available when the Supra manual was published. Modern oil's at SAE viscosity 0W-20, 5W-20, 0W-30 and 5W-30 easily cover the temp ranges (especially in cold climates) most of us operate the motor at...oils have simply improved that much over the last 20 years. Bottom line: Take the Supra manual oil chart with a grain of salt.

Your local Supra mechanic is not lying to you...he just doesn't know what he doesn't know and the previous owner of the car believed him
Here's what you hear from the guys that tell you to run a 20W-50 in the 7M:

1) The manual recommends it - False
See above. The manual does not specifically recommend a 20W-50...it's just one of the oils listed that are "approved". It also recommends a 10W-30...an oil that covers a wider temp range. Completely ignores that API SF and SG grades are obsolete.

2) A thicker oil will keep the bearings from getting hammered; provides a cushion between the bearing and crank journal/rod end - False
Main and rod bearings operate in the hydrodynamic lubrication region. I'll forego the technical explanation...think of it like a water ski. The rotating motion "floats" the bearing between the rod end and journal clearances...the bearing never touches. Almost every motor from the 1980's was designed with bearing clearances to run with an oil at 10-11 cst at operating temp. That viscosity is smack in the middle of a 30W range at 210 deg F...just below the 195 deg F the 7M is designed for.

3) A 20W-50 will increase oil pressure and keep the bearings from touching the crank journal/rod end - False
A thicker oil will increase oil pressure in the 7M, but only to a point. The design of the 7M has the oil relief valve set at 63-71 psi...over this oil is simply routed back to the pan. More importantly, the oil cooler valve on the stock filter head operates at 40 psi and you have a controlled "leak" from the oil squirters on a turbo motor. Pressure is resistance to flow...a 20W-50's increase in pressure means that it does not flow as well through the bearings or to the top of the motor. Considering a 20W-50 oil is 3-4 times thicker cold than a 5W-30, it's significant. This means a couple of things:
- On a cold start, you will have restricted oil flow where you need it the most.
- The oil relief valve will cut the flow further by opening at the higher pressure and dumping oil back into the pan.
- It will take longer for the oil to get to the cam shafts...the small diameter hole in the middle does not facilitate flowing high viscosity oil. Since the oil flows from front to rear on the cam shafts, it is going to take the #6 cylinder valves the longest to get the oil flow needed.
- The oil squirters spray pattern on the cylinder walls will degrade with a high viscosity oil...especially cold. It's simple...higher viscosity, lower velocity.
Oil pressure has little to do with the way an open bearing (like rod & main bearings) works. Like I said, these bearings depend on hydrodynamic lubrication to function...saying increased pressure will improve this is a very basic misunderstanding of how the bearings really work. The ONLY time I could see using a 20W-50 from a bearing standpoint is if you've built the motor for it by opening up the bearing clearances to get the flow...you will see some very experienced engine builders do this, mostly on race cars that get re-built every season anyway.

4) Thicker oil "stays put"...it will stay in the bearings and on the valve shims after you shut down the engine - False
When a 50w oil is at operating temp, it thins out just like every other oil does...just less so. It has a viscosity of 16-22 cst, approx 50% more than a 30W does at operating temp. This is not near enough to make the oil "stay put" when you shut down a motor at operating temp...it will drain from the top of the motor and from the bearings just like any other oil does (isn't gravity a bitch). What is important is to get oil back where it's needed, especially cold...this is where a 0W-30 or 5W-30 is far superior...much better flow means the oil will get there fast.

5) A 20W-50 handles heat better and resists breakdown - False
Any modern motor oil does an excellent job of resisting heat breakdown regardless of weight. Oil and the additives in it are very stable to well over 250 deg F...if you see those kind of temps in a 7M oil system, you have a lot bigger problem to deal with. Since a thinner oil flows much better, it also does a better job of keeping the bearings cool...another major function of oil in any motor.

The same folks that promote a 20W-50 will also say that a 0W-30 is "way too thin"...again, a basic ignorance about oil grades and what the numbers on the bottle mean. Always remember the 1st number (0w in this case) means what the viscosity is "cold" at 40 deg C...the 2nd number is what the viscosity is "hot" at 100 deg C. A 0W-30 is not thin, the German Castrol 0W-30 I recommended to you a while back is an excellent case in point...at 100 deg C it has a viscosity of 12.1 cst. A 40W oil viscosity starts at 12.5 cst on the SAE charts...the German Castrol is pretty close to a 40W oil at operating temp. The beauty about this oil is it also flows quite well cold and is Group IV PAO based...if you want to read more, I did a write-up on it in this thread, post #4:
http://www.supramania.com/forums/showthread.php?t=38768

Like JJ has told me many, many times...telling folks that a 20W-50 is not an optimum oil to use in the 7M is like "shoveling sand against the surf". The reason is what you heard from your local Supra guru...the misinformation and ignorance on how an oil works keeps getting passed along via word of mouth...mechanics are the #1 perpetuators of this myth. In all fairness, there are a very few instances where a heavier weight oil is called for...if the motor is built for it or if you already have worn bearings (just putting off the obvious here). Also, a 20W-50 is not going to kill your motor off the bat...it's also not what's best for it either. Plus, gas mileage will suffer using a thick oil. In 99% of the cases where you have a healthy motor, a 0W-30 or 5W-30 will do a better job....especially if you happen to live in the northern tier of the US or any other climate where below freezing temps are common.

I changed the title of this thread...I welcome any and all comments. Just a warning though, if you say "I've been using a 20W-50 with no problem"...my answer is going to be simple. Of course you can...it's just not what's best for your motor and you need to educate yourself as to the reasons why you use it. I base my reasons on the facts...do you base your reason on hearsay without knowing why? Might want to think about it before you respond

 

[jdub]

Wow, thanks for the very educated response.

I'll try to get an oil change done this weekend, with the European Formula 0W-30 if I can find it. It's at alot of AutoZone's in my area. Thanks for the write-up.

I hope that him running that thick of an oil hasn't f-ed up the JDM motor he put in it.

-Matt

Darn, all of my AutoZone's no longer carry it, what would be a good substitute?

I heard from some people that Mobil 1 10W-40 was good.

-Matt

You're welcome Matt!
Just a warning...if you hit a guy that advocates using a 20W-50 with the above info, the discussion will degrade to "well, I've always used it and in my experience its the best". Problem is, they can't tell you why...nothing to back up their reasoning other than "I've always used it" or "my mechanic recommends it" or "in my experience". I'm not discounting experience, but concerning oil there is way too much BS flying around.

A lot of AutoZones still have the GC, but it is discontinued and you'll be buying what's left. Some even have the older stuff...there's a code on the bottom that starts with an "M". The 1st two numbers are the year, the next three are the number of days into the year it was made. If it's a "M04", it was made in 2004 and it is the older "GC Green" (the oil is actually green). That is the best GC out there...made before a slight formula change in early 2005. If it is the CG Green, buy all you can get

In 2005, Castrol changed the formula slightly and removed the green dye...this is the GC Gold. It's still one of the best oils out there.

You have to go to the AutoZones around town and look...the key is "Made in Germany" on the back of the bottle. I was able to go to 4 AZ's and pick up a total of 4 cases...should last me quite a while...3 of them were the GC Green

You also might be able to get some GC at an Audi or VW dealer...it's the factory fill on those cars.

Mobil 1 is a good oil, but keep in mind it's a Group III hydrocracked dino base stock oil. If you're going to use a Group III oil, go with Penzoil Platimum 5W-30 (excellent add pack). If you really want to use a 10W-40, Castrol SynTec 10W-40 is slightly thicker than the GC at operating temp and flows quite good cold...it's actually thinner than the Castrol SynTec 5W-40. It too is a Group III hydrocracked base stock oil.

The only other "true syn oils" commonly available are Red Line (Group V ester base), Royal Purple (primarily Group IV PAO w/ ester add) and Amsoil Series 2000 (Group IV PAO based).

 

[jdub]

so what would be the best oil to use for a 2jz-ge overall?

Take a look at my response to Matt above...if you can find the GC, it's hard to beat that oil.

The 2JZ-GE is a NA motor, so using a true syn oil is less of a factor. You don't have to deal with the heat from the turbo. If it's in good shape, the Pennzoil Platimum would be an excellent choice so long it keeps oil pressure in spec for the motor. Otherwise, the Castrol SynTec 10W-40 would be another good choice.

well i plan to NA-T my motor with N20 later on so i guess pennzoil platinum is the better choose but later on the road for im planning on the car should i stick with the same oil?

On a turbo motor a PAO or ester based syn oil is best. That means Red Line, Royal Purple, or Amsoil Series 2000...all are available in 5W-30 or 0W-30 viscosities. If you can get a supply of the GC, it is very good. Of the others, Red Line is my 1st pick...a pure ester based oil is top of the line...can't get any better and it has an excellent add pack.

Supracentral is using Royal Purple in his Mk IV turbo with good results...look at this thread:
http://www.supramania.com/forums/showthread.php?t=41712

There's a rumor that Wal-Mart is selling RP now

You also want to use a good filter...Wix, NAPA Gold, and PureOne are all excellent choices. The Mobil 1 filters are also good, but a bit pricy...they are a Champion Labs filter with a synthetic media. If you can get them on sale, it would be fine to use. However, the others I mentioned are a bit better choices.

BTW - I'm responding this way to keep the post count down...got a feeling this thread might "blow up"

Well i found this forum that has an FAQ just on GC Oil. Pretty neat

http://theoildrop.server101.com/forums/showflat.php?Cat=0&Number=711450&an=0&page=0#Post711450

GC has almost a "cult like" following at the BITOG forum. Not into that mentality myself, but I know an excellent oil when I see it

Like any forum, you have to wade through the BS to get at the true info...BITOG does have a lot of very knowledgeable guys (Petrol Engineer types) as members though. Doesn't take long to figure out who knows what they are talking about

 

[jdub]

Pennzoil 5W-30 sounds like my best shot then, as it's available at my local Wal-Mart. However, how does it compare with the Valvoline synthetic?

-Matt

Here's the Spec sheet on Valvoline Synpower oil:
http://www.valvoline.com/products/Synpower.pdf

IMO it's on par with the Mobil 1 products. The biggest reason I like the Pennzoil Platinum is the add pack formulation...they have taken the technology up a notch for the Group III base stocks in the past couple of years.

So do you think the previous owner has caused damage to my motor by running that thick oil?

-Matt

I doubt it. He just wasn't doing the motor any favors.

 

[jdub]

I've been using a 20W-50 with no problem...or is it 5W-20? Doesn't matter. Oil is oil right?

So this guy thinks not using molasses leads to rod knock. That's a hoot. If he had any sense he'd realize it's closer to the other way around, especially when combined with cold start up temps.

LOL! That statement (not using a 20W-50 causes rod knock) is exactly what set me off on writing another novel on this subject. It's just sooo wrong for so many reasons. Just could not let that one pass...I guess it's my mission here to shoot that kind of total ignorance down.

Yeah...I know...where's my shovel?

BTW guys - JJ is running Pennzoil Platinum 5W-20 in his 7M and summer is just around the corner :icon_eek:
So far with great results.

 

[jdub]

John, I'm going AutoZone raiding when I get off of work. Do you recal off the top of your head if the "M" label was on every bottle (on the bottom right?) or was it just the boxes that they were shipped in?

It's on the bottom of every bottle...some of the early 2005 codes are also the GC Green. The best way is to open one and pour a little into the cap...it's green alright

In any case, the GC Gold is very good...I'd buy it in a heart beat.

Looking for a 0W-30 that would be an equivalent to the German Castrol?

Brad Penn makes it... and here is their link.

http://www.bradpennracing.com/Products/racingoils.html

It is known as "The Green Oil."

Well...not exactly "equivalent". Here's the data sheet for the Penn Racing Oils:
http://www.amref.com/bp_pb/7115_17_19_26_7150_BP_PENN-GRADE_1_Racing_Oils_PB.pdf

This makes the Penn oil a blend of Group II or III base stock with either PAO or ester as the synthetic component. German Castrol is a PAO base stock oil with some esters as part of the add pack...100% synthetic. The data sheet alludes to an API SJ rating, but I could not find it on the website. It is green though...perhaps the same Black Forrest elves had a hand in making it? LOL.

It looks like a strong add pack. ZDDP is Zinc dialkyl dithio phosphate, a family of zinc salts of dithio organophosphates...it is the dominant anti-wear agent present in motor oils. Soluble moly is the other most common anti-wear agent. GC contains both ZDDP and moly. Usually the amount of ZDDP is minimized in most motor oils you see on the shelf due to the zinc and phosphorus emissions damage potential to catalytic converters. This oil may just have a bit more healthy dose. Plus the sheet says it has a strong dose of detergent and dispersant additives...something you normally don't see in a racing oil.

The cold/hot viscosities look good, especially the cold viscosity. The only thing I can see that's a bit odd is the flash point...it's low for this kind of oil. Leads me to believe Penn is using low viscosity Group II cuts to make the "0W" part of the viscosity grade. This could very well impact NOACK Volatility which determines how much weight loss an oil experiences through volatization. Meaning, you may experience higher than normal oil loss due to vaporization over time.


Give it a shot. Do a virgin oil analysis (VOA) and used oil analysis (UOA) at the 4000 mile point and post up the results.
You might just have a winner

 

[jdub]

a good place to use 20w 50 is if you have a stubbon oil leak on and ol engine or shitty valve stem seals. Since when the oil cools it becomes thicker and tends not to leak as much.

Also I used to use 20w50 only in the summer... I liked the added heat protection as I often forgot to turn on my elec fans until i hard wired them to the ignition.

Don't you think it just might be a better idea to fix the cause of the leaks?
Of course, on a old motor it really doesn't matter...might as well hasten it's demise and put it out of it's misery.

I would like to know one thing though...how do you figure 20W-50 gives you added heat protection?
Your mechanic tell ya that?

Well since in live in az. The temp here is like 100 at night and 115-120 in the day in summer would a thicker oil be need then? BTW this is for a 5m-ge. Also would 20w-50 be better is your car burns oil very badly my freinds honda burns like 8 quarts per tank of gas which is like 10:1 oil to gas ratio lol.

If you take a look at any oil data sheet, the "cold" viscosity is rated at 40 deg C...that's 104 deg F. In AZ, all that happens is it just takes the oil less time to reach operating temp (100 deg C). It also points out the need for a good oil cooler in this environment. BTW - I live in Phoenix myself

Let's use Mobil 1 EP as an example. The 5W-30 has a viscosity of 61 cst at 40 deg C...the 15W-50 is 138 cst at 40 deg C. That's over twice the viscosity at engine start...in cooler climates, the viscosities are even higher with a bigger difference between the grades. Take a bottle of each oil and put it in the freezer for an hour, then pour side-by-side on an inclined cookie pan...the difference in viscosity will become graphically evident.

Once the oil is at the 100 deg C ops temp, the viscosities drop significantly...the 5W-30 is 11 cst and the 15W-50 is 18 cst. Still quite a bit of a difference, but less impact on oil flow through the engine vs. cold. Here lies the problem...the time it takes to warm up the oil is cutting oil flow through the motor. This is not doing your bearings any favors. Also, engines from the '80's were designed to run at a viscosity of 10-11 cst hot...that includes the 5M.

I run a 0W-30 all year in Phoenix...I also have a cooler that's twice the size of the stock one. If your 5M has a lot of miles on the engine, a 10W-40 may be more appropriate due to bearing wear already present. I would never use a 50W oil unless I built the motor to handle it.

Concerning your friend's Honda...his motor is FUBAR'ed. There is no oil or "magic additive" that will help...he needs a new engine

 

[jdub]

Please tell me people DON'T actually think a thicker Oil will leak less in a leaky motor........ :nono:

IJ - sad as it may be...people think that exact thing. The above posts are a case in point....it's just not true. Thicker oil will not stop a leak. Fixing the seal, gasket, or O-ring will though

 

[jdub]

Beeing a noob concerning oils and finding the infomation in this thread a great find, I got a question concerning Mobil 1 5w50 or Castrol Synth 5w50. I'm in eastern Canada where the weather gets a mighty cold, but my Supra never sees a snowflake in winter, the car hits the storage garage from November to May. The coldest it will see is maybe 40F overnight during a late fall event but summer temps can rise to 100f and a spirited ride can show 210 on the aftermarket water temp gauge.
On the first day of storage after riding the car to get it to opperating temp, I do a oil / filter change and put in a 5w50 from one of the above brands. At least once a month I spin the engine to lubricate it (do not start the car, just spin the engine until I see pressure on an aftermarket gauge).
I, too, was under the influence of word of mouth that a w50 oil would be better for a car that sees extended use (taxi or such) in hot weather. My experience here is that while I used to drive a Honda as a courrier, and while doing an oil / filter change every 2 weeks, I found that cheap oil always (Esso / Shell / No name brand) used to get used up quickly in the honda moter while brands like Castrol or Quaker would stand up and not "dissapear" from the high milage / long day usage engine. Hey, it is only an experience, there is no facts like you guys supporting the above.
Other than the above recommeded GC and Pen oils as well as RP, etc, do the Mobil 1 and Castrol Synth stand up to the test? After reading this and the other Oil post, I am thinking of moving down to a 5W30 or even the 0W30 GC (found some at Walmart).
Any info on the 5w50 oils is welcome.

Mobil 1, Pennzoil Platinum, and Castrol SynTec are all Group III oils...extensively hydrocracked dino oil base stock to be precise. Group III by definition is not a synthetic oil...the companies get away with marketing it as such because they use "synthetic technology" to produce the base stock. Group IV & V are the synthetics...PAO and ester are the most common. These are Amsoil, Redline, GC, and Royal Purple. I'm not saying the Group III "synthetics" are bad oils, they just are not true syn oil and paying a syn price for them is, well, unsat.

Any oil with a big viscosity spread (like a 5W-50) requires a lot of viscosity modifiers for it to perform to spec. That means there is less actual base stock oil by volume to actually lube your motor. It also makes "viscosity creep" much more likely....viscosity modifiers are one of the 1st things to degrade as the oil goes through heat/cool down cycles. The viscosity will move toward the base stock viscosity...in a 5W-50's case that will be toward the high end...it will lose the ability to act as a 5W when cold. BTW, Group IV & V oils do not require as much viscosity modifiers to perform to grade.

All of the above Group III oils are very good...the Pennzoil is my choice due to the advances they have made in formulating this type of oil. All can go 5000 miles between changes with a good filter. They are not in the same class as the Group IV & V oils though...since you can still get the GC (it's at Canadian Tire too), it would be an excellent choice...especially for your climate.

I'll throw something out concerning storing your car for the winter. I would change the oil to a decent 5W or 10W-30 dino oil (Wal-Mart SuperTech oil and filter), drive it for a week and put her up for the winter. When you're ready to play for the summer, change the oil to GC, use a PureOne or Wix filter and you will be good until November (assuming 8-10000 miles). If you hit the 4000 mile point during summer, change the filter and add enough GC to make up.

 

[jdub]

I keep hearing this. It was my impression that only the EP versions were found to have a mix of group iii in it, but was still mostly group iv oil.

Can you show me proof?

Mobil 1 uses Group III + AN base oils including polyalphaolefins (PAO)...however, the primary base stock is Group III.

In 2006, the results of a gas chromatography test on Mobil 1 5w-30 EP were posted by an industry expert on the popular motor oil discussion website BITOG. It showed the oil to be primarily composed of a less expensive, Group III processed mineral oil. Until this time, Mobil 1 was believed to be a true synthetic, utilizing a Group IV (PAO) base stock. The release of this information has led to a backlash against Exxon Mobil's lubricant products in many automotive communities. Ironically, in 1999, Mobil fought Castrol's change in formulation to a Group III base stock in motor oils being marketed as fully synthetic. Mobil claimed that Castrol was deceiving their customer base, while degrading their products. The National Advertising Division of the Council of Better Business Bureaus eventually ruled that Castrol could continue to market their SynTec line as a fully synthetic motor oil. Exxon Mobil currently refuses to comment on the primary base stock of their Mobil 1 series of oils. This has only added further confusion over the exact definition of the term "synthetic oil."

This is the last I have seen...that does not mean it won't change though
Keep in mind that Mobil 1 EP is their top-of-the-line...why would they change the EP line and not the rest?

Plus there is this Exxon US Patent application...kinda spells out where Exxon is going concerning Group III base stocks
Looks like they will be using a blend...Group III, PAO and AN (alphaolefins)...I'll bet ya the base stock will be mostly Group III. Too much PAO and/or AN will cut profit margins.

http://appft1.uspto.gov/netacgi/nph...81".PGNR.&OS=DN/20060211581&RS=DN/20060211581

 

[jdub]

^interesting. What is the purpose to changing the oil to a group III before storage? I thought it is best to keep the engine free of dino oils is you are running synthetic.

There will be a very small amount left in the motor. You want to drain old oil prior to storage to ensure minimum contamination/combustion by-product presence...no point in using expensive oil for this purpose. The oil Mattjk mentions below (SuperTech "synthetic" 5W-30) would be a good choice. When you re-fill with the "true syn" oil, the amount left in the motor will be a very small percentage by volume.

I've started using SuperTech 5w-30 grp III hydrocracked "full synthetic" in all my cars now. Mostly because of cost because I drive all my cars alot, it oil changes really start to add up... I did alot of research on it before using it and seemed to have a good rep and good add pack. I figured it passed API's grp III synthetic rating, so it's most likely better than a regular "dino" oil, at an even lower cost.

SuperTech synth is $2.58 a qt, and regular valvoline is $2.89 a qt.

What is your opinion on it, jdub?

Thanks.

SuperTech is actually a pretty good oil...IMO your research is correct
The filters too (made by Champion). I wouldn't run it in a turbo car on an extended basis, but on a general type motor, it will give you good service.

So for winter storage, pennzoil platinum would be a good choice to run for a week on a turbo car?

Overkill IMO...the SuperTech will be fine. Running it for a week is not going to cause any problem with coking or engine deposits due to heat. The only reason to run it at all is just to get it through the whole system to get everything inside "freshly oiled"...a day or two would likely be enough.

So you think this is good oil on a regular basis for non turbo cars? I just switched my X-runner and Corolla S to this kind of oil (5w-30) with Napa Nascar oil filters (made by Wix)

It should be fine to use. The NAPA Nascar is the same as a NAPA Silver filter...it's a marketing thing. Use the NAPA Gold...better filter.

 

[Nick M]

To put the oil numbers in layman's terms, they represent the oil's ability to flow in different temperatures. They don't represent the amount of protection on the bearing.

In fact, according to research from scientists that post on physicsweb.org, the higher the numbers, the more friction the oil has.

Like others, I was to be able to sit in oil classes from Castrol and Penzoil through the years. And guess what, neither contradicted the other, or the information given in this thread and the others about oil and its properties. The information posted here is good.

 

[jdub]

Ive been running 20w50 a while now, I picked it because I thought it would be best in the Arizona heat. I run 20 50 in my motorcycle(based on very sound advice from many people i trust) and had no problems there.

After reading this however im looking to run straight 30 now in the supra. I dont have any leaks so Im not trying to band aid anything. I really just thought after looking over oil charts(no oil education) that it was the best for this dam heat. When it is cold I let the motor come up to temp before driving, being NA I figured it didnt matter ha.

Don't run a straight 30W...you want the oil as low a viscosity as possible for start up. Use a 0W, 5W, or 10W-30.

I thought 10w30 wasnt as good in high temps. Sigh Im going to have to read more to understand this whole oil thing ha. Im going to change my oil in 500 miles so I got until then to decide ha.

oh, Im not saying your wrong, just saying I need to learn more to understand Why you recomend what you do

It's ok
Read this thread plus the links at the bottom...helps to see where I'm coming from:
http://www.supramania.com/forums/showthread.php?t=38811

Always keep in mind the 1st number is the "cold" viscosity or winter temp...the 2nd number is the viscosity at ops temp (100 deg C).

so im kinda confused are you saying that the 0w means that it is good in 0 degree weather, and the second number is what?

That 1st number always seems to cause confusion...it is misleading. It is the viscosity of the oil cold; the temperatures experienced during "winter" weather. What's funny is SAE uses a viscosity temperature of 40 deg C (104 F)...not very cold huh? Even more confusing is the SAE uses cranking/pumping viscosity measured in centipose (cP) to grade the 1st number and uses kinematic viscosity measured in centistrokes (cSt) to grade the 2nd number (viscosity at ops temp). Perhaps this chart will help:
http://www.tribology-abc.com/abc/viscosity.htm

I would like to point out that the temperatures experienced by all of us in the winter is considerably colder than 40 deg C. That means the oil is thicker than you would expect...a lot thicker, even with a low 1st number. That is the major reason a 15W or 20W-50 is not good for the motor...it does not flow well cold. Keep in mind an oil always thins out (lower kinematic viscosity) as it gets hot...it never thickens as it warms up.

All you need to remember is the oil will have a viscosity of 0W, 5W, 10W, etc (or thicker) at cold start-up. Once the engine reaches ops temp, it will have the viscosity of the 2nd number...30, 40, 50, etc.

I'm starting to repeat myself
Read the above posts carefully...also, the "Motor Oil Basics" sticky in this section covers this quite well.

 

[jdub]

As far as I know my car has been running 20w50 for the last who knows how long (only had the car for about a month).

Other than the posts here I'm pretty much in the dark as to what I should be running. The oil still looks clean and I know 20w50 is frowned upon. Should I be looking at the 0w30 that's been recommended or something like 5w40? I picked up some 5w40 made in USA before realizing that walmart carries 0w30 made in Germany. Should I try and return and go for the 0 or stick with what I've got?

The GC you are referring to is on the "thick side" for a 0W-30...it's pretty close to a 40W at ops temp. For you guys that live up north, it's a perfect choice. Flows very well cold and gives bearings the viscosity to keep them running smoothly...especially if your bearing are showing wear from many miles. I'd return and switch to the GC in a heartbeat.

 

[jdub]

Comment please about using the 20w-50 when racing the car on a track? My oil temps hit 240 - 250F and it seems that the heavier oil will do better at these high temperatures. Hotter oil gets thinner and I feel more secure having the heavier oil in it.

The only times a heavier oil may be better for the bearings is:
1) you have a lot of miles on the motor and you have bearing wear
2) You have built the motor to handle the heavier oil. You intentionally have bearing clearances on the high side of spec to prevent wiping at high rpm and deburred the crank oil channels. You have modified the oil cooler loop to a full flow, thermostat controlled set-up. Your filter is high flow like the Canton. The oil lines are AN10.

Even doing these things, a 10W-40 is more appropiate IMO...if you use a heavier weight, you need to pay attention to the cold viscosity and get the lowest available. You also want the oil to heat up to 100 deg C as quickly as possible, hence the thermostat in the oil loop.

The bearings need flow to function and to last...the goal is to faciliate that flow, especially cold. Basically you want the oil viscosity to meet what the hardware requires. For 90% of the 7M's out there (including modified), a 0W-30 to 10W-30 is more than sufficient.

Consider the amount of time the car is on the street vs the track. Using a 20W-50 to handle high temps is a band-aid...keep in mind the oil takes time to get to that temp and during that time, you are restricting oil to the bearings. A much better solution is to get a cooler with the capacity to keep your oil at 100 deg C.

 

[88mkiisupra]

the only car I've seen that calls for 20-50 is my 77 BMW. Every other car I have owned Has called for a five or ten-w-30. I am however running 0w-30 in my 7m as the owner before me had done.

 

[jdub]

Wow. It's been quite some time since I dropped by SupraMania. I think the last time I was here, I had to rejoin from when the site was hacked, back in 2005. I do like the articles now posted here about the science of oils.

That kind of disappoints me to learn about Mobil 1 not being a fully synthetic oil. Leave it up to Exxon to lie/cheat/steal and lack any answer to the public in regards to their responsibility (where have I seen this before?) Hardy har...

At any rate, I have been using 15W-40 in my car since I replaced the head gasket. The engine is a high mileage 7MGTE, although The cylinders did look excellent when we pulled the head.

I understand oil viscosity ratings are measured @ 40C - 100C for each advertised number. I'm using a standard thermostat to hold the engine right at about 180-185 F. Do you know what the oil temperature inside of a turbo reaches? I understand that they differ on each application, but my only concern is that regardless of bearing wear/tolerance measurements, that a lower viscosity (2nd advertised number @ operating temp) might actually be significantly higher inside the turbo, versus the rest of the oil in the engine?

I do agree that 20W-50 seems a bit high, but I'm wondering if dropping numbers past a 10W-40 wouldn't be a good idea for a turbo'd engine?

I'm not really arguing here, but rather curious, among being a bit dumbfounded (yet somehow not surprised) about Mobil 1 oils. I think I may end up changing from Mobil 1 in my other cars to a fully synthetic oil. I would have never purchased it with the intention to change my cars over to synthetic if I had known that it wasn't fully synthetic base.

I'll have to read up on the Oil Basics page as well as the Viscosity page that you linked.

I'm curious as to what would be best for a turbo engine and I'm really curious to see what the oil temp numbers look like at different operating ranges in a Toyota C-26 and other turbochargers.

Thanks for the information!

Dave

The temps inside the turbo are significantly higher (I don't know the exact temps) and the oil going through the turbo loop is directly from the pump to the pan. A lot of oil is supplied to the turbo as a result and it's not in the turbo long enough to case break down. Also, think about it for a minute...had you rather have the better flow (and cooling effect) a thinner oil provides or decreased volume from using a thicker oil?

Motor oil in a turbo engine is a compromise due to the reason you've brought up. IMO, keeping the main and rod bearing "happy" are a more important task for the oils we use. Thinner oil flows much better keeping the volume supplied to the bearings sufficient to prevent the surfaces from touching. If high oil temps become a problem, dump the stock filter head and cooler and invest in a thermostat controlled, full flow cooling circuit.

Dave, you nailed it...it's not that Mobil 1 is a bad oil, it's Exxon's lack of disclosure concerning their top-of-the-line oils in the interest of increasing profit margins. Considering the obscene amounts of money that company is making, it kind of pisses me off.

 

[flubyux2]

im using 20w50 right now, just a conventional "generic" Advance auto/Discount Auto oil. thats what i had before this current cycle too. ive only had this motor for these 2 oil changes. ive switched to the NA oil filter mount, Summit single-element relocation w/ 1/2" ID lines. im using the Ford V8 PureOne filter. its plumbed before my FC3S bypass oil cooler.

the catch is, i had the oil cooler hooked up backwards for the first oil change interval. so when the t-stat began to close to route some oil thru the cooler, the oil pressure forced the valve shut and the Full volume of oil was forced thru the cooler. when this happened, my oil pressure would decrese dramatically. IE: 10-15psi at ANY rpm when the oil warmed up. i have a feeling i wiped the bearings. my oil pressure isnt as high as i feel it should be with my oil system and shimmed oil pump. the only variable i cant confirm is whether this new oil pump is a GE or a GTE unit. my oil pressure readings are 30psi at 2500 when cold. hot oil pressure at 2500 is 25psi. hot idle oil pressure is 5psi. IMO, i think thats too low considering my oiling system.

am i doing my engine more harm than good w/ the 20w50 conventional at this time?

also, i seem to have leaky injectors as my car floods when it sits overnight. in my dyno video, my valve covers are vented and it looks like a 2 jets of steam; the emissions disappeared immediately and did not linger. is it possible its entrapped moisture vaporizing? my car sat for about 6 weeks with no catch can system. after driving my car around for a few days after that, the PCV emissions significantly reduced but were still present and reek of raw fuel. will raw fuel emulate steam when boiled off the engine oil?

also, regarding bypass oil filters; i read up a bit on Frantz TP systems on my diesel forums. it really got me interested. the original poster had his oil analyzed every 2500 miles and each time the results came back positive. i beleive he ran on that interval for 15000 miles simply adding make-up oil during the TP roll changes and that kept the add packs adequate. the oil analysis company said he could have ran the oil even longer if he desired. it removed quite a bit of carbon black/soot from the oil as well. do the TP bypass systems remove sub-micronic contaminants?

 

[jdub]

Wow...you got a lot going on with this motor

I'm using 20w50 right now, just a conventional "generic" Advance auto/Discount Auto oil. that's what I had before this current cycle too. I've only had this motor for these 2 oil changes. I've switched to the NA oil filter mount, Summit single-element relocation w/ 1/2" ID lines. I'm using the Ford V8 PureOne filter. its plumbed before my FC3S bypass oil cooler.

the catch is, I had the oil cooler hooked up backwards for the first oil change interval. so when the t-stat began to close to route some oil thru the cooler, the oil pressure forced the valve shut and the Full volume of oil was forced thru the cooler. when this happened, my oil pressure would decrease dramatically. IE: 10-15psi at ANY rpm when the oil warmed up. I have a feeling I wiped the bearings. my oil pressure isn't as high as I feel it should be with my oil system and shimmed oil pump. the only variable I cant confirm is whether this new oil pump is a GE or a GTE unit. my oil pressure readings are 30psi at 2500 when cold. hot oil pressure at 2500 is 25psi. hot idle oil pressure is 5psi. IMO, I think that's too low considering my oiling system.

am I doing my engine more harm than good w/ the 20w50 conventional at this time?

Whatever happened to your oil cooler circuit, 10-15 psi at any speed much above idle is bad...you very well could have FUBAR'ed the bearings. The TRSM looks at hot oil pressure at idle & 3000 rpm...your idle is actually ok per the manual, but should be much higher running a 20W-50 (in the 10-20 psi range) especially running a shimmed pump. It's low at 2500 rpm IMO...again, considering the weight oil and shimmed pump. The stock filter head relief valve is not a factor either since you removed it. At this point, I don't think the 20W-50 is harming a thing...in fact, it might be the only reason your engine is not knocking. If your bearings were burned to the point where the clearances opened up, this thick oil will fill it. I would not change oil weights at this point and would consider taking a look at those bearings before it gets worse.

also, I seem to have leaky injectors as my car floods when it sits overnight. in my dyno video, my valve covers are vented and it looks like a 2 jets of steam; the emissions disappeared immediately and did not linger. is it possible its entrapped moisture vaporizing? my car sat for about 6 weeks with no catch can system. after driving my car around for a few days after that, the PCV emissions significantly reduced but were still present and reek of raw fuel. will raw fuel emulate steam when boiled off the engine oil?

Besides the obvious need to fix this, too much fuel can easily wash down the cylinder walls and cause excessive ring wear. This will increase blowby and get fuel in the oil causing dilution...this is not good for the bearings either. When oil gets hot, it does burn off water and vents it through the PCV system...condensation (especially in a humid climate like FL) can make the vapor increase if the car sits. Fuel will do the same thing and fuel vapor can easily look like water vapor with one difference...it can explode. You really need to get this corrected...fast.

also, regarding bypass oil filters; I read up a bit on Frantz TP systems on my diesel forums. it really got me interested. the original poster had his oil analyzed every 2500 miles and each time the results came back positive. I believe he ran on that interval for 15000 miles simply adding make-up oil during the TP roll changes and that kept the add packs adequate. the oil analysis company said he could have ran the oil even longer if he desired. it removed quite a bit of carbon black/soot from the oil as well. do the TP bypass systems remove sub-micron contaminants?

The Franz is an excellent bypass filter and it filters down to 1 micron...way below where a particle can cause damage to internal motor parts. You don't have to change the TP roll as often on a gasoline motor...there is no soot to deal with. I have a MotorGuard that's going on my Toyota truck...basically the same thing as the Franz, but it has to be modified with an orifice to restrict flow. The problem with these filters is where to put them...they're kinda big. You can mount where the charcoal canister is and get a JDM charcoal canister to mount under the wheel well. With these type filters, syn oil and doing oil analysis, you can go 15,000 miles NP between oil changes.