what is the optimal coolant temperature for a 7m motor?

[chefma70]

my autometer gauge is reading 185 when im cruising . i have no clutch fan shroud and no fans whatsoever(other than the clutch fan). and im also running straight coolant no water at all.

is this a good temperature to stay at?

what temp do you 7m guys run your motors?

 

[Sawbladz]

Why in the hell would you do this?

Not having a fan shroud, aux fans or undercover (assuming this one but I doubt I'm wrong) are problems that should be addressed. Not even going to get in to the straight coolant...

 

[carter]

in the summer mine ran around 160-170 if i remember right... idk

 

[Clip]

normal cars will run a 50/50 mix of coolant/water. i'll run a lot of water in the summer and 50/50 in the winter. but i've got the stock fan, shroud and aux fans, plus the undercover.

 

[Poodles]

 

[TurboStreetCar]

Straight coolant. Why? Added expense for worse heat transfer.

As ive said before the shroud and undercover aren't necessary unless you have issues with your cooling system. Sure they help, but if your overheating because you don't have them, you have other issues.

Put a stock thermostat in the car and make sure its purged all the air out. Then as Poodles post shows, somewhere near 190 degrees Fahrenheit is good.

 

[SupraMario]

Why in the hell would you do this?

Not having a fan shroud, aux fans or undercover (assuming this one but I doubt I'm wrong) are problems that should be addressed. Not even going to get in to the straight coolant...

Whoa, chill out there skippy.
He came looking for an answer, and not a snappy remark.

Its always a good idea to have a fan shroud, I know plenty who do and don't have them but as nose said, if your over heating from not having one its something else. Get a fan shroud, its just good measure. Also Anti-Freeze isn't great at transfering heat, at least 50/50, I run straight water in the summer time because it really does keep the car cooler. So first thing I would replace some of the anti-freeze with water, get a good 50/50 going, because you really don't need it unless your at the north pole.

 

[jdub]

The ECU ops range is 176-212 deg F. Below that range you are in warm-up enrichment...the ECU adds fuel on a decreasing linear scale to the min temp as the coolant warms up. Above 212 degs, the ECU pulls timing to prevent detonation. Not as severe as inop knock sensors, but it will affect how the motor runs.

Chiefma70 - your coolant temp is about as good as it gets
(assuming it doesn't take forever to achieve that ops temp)

For you guys running straight water, you need to have some sort of anti-corrosion inhibitor added. While straight water will have a minimal effect of better temp transfer to the radiator, the "benefit" is far outweighed by what the water is doing to your block. If the engine is running within the ECU ops range, that is exactly what it's suppose to do. Running cooler is not better.

IMO straight water is only good for a pure race car, not one that is run on the street with the water sitting in the block for months at a time. Use a 50/50 mix of Toyota Red (phosphate), Zyrex Import (it's equivalent) or Zyrex G05...your motor will thank you.

 

[Boosted516]

Whoa, chill out there skippy.
He came looking for an answer, and not a snappy remark.

Its always a good idea to have a fan shroud, I know plenty who do and don't have them but as nose said, if your over heating from not having one its something else. Get a fan shroud, its just good measure. Also Anti-Freeze isn't great at transfering heat, at least 50/50, I run straight water in the summer time because it really does keep the car cooler. So first thing I would replace some of the anti-freeze with water, get a good 50/50 going, because you really don't need it unless your at the north pole.

yea antifreeze is a horrible coolant, it just gives a lower freezing point and higher boiling point. water is the optimal coolant, many run 100% water if they live in an area where it doesnt get too cold or too hot. but when you go above 50/50 you see the opposite effect, it will not only be a horrible coolant but the freezing points will rise and boiling point will drop. so defintely get a 50/50 in there

 

[jdub]

yea antifreeze is a horrible coolant, it just gives a lower freezing point and higher boiling point. water is the optimal coolant, many run 100% water if they live in an area where it doesnt get too cold or too hot. but when you go above 50/50 you see the opposite effect, it will not only be a horrible coolant but the freezing points will rise and boiling point will drop. so defintely get a 50/50 in there

Coolant does in fact increase the boiling point, but the primary factor is the system is pressurized. One problem running pure water is if system pressure is lost due to a leak...instant boil over. The only advantage is water's heat transfer ability...when water's disadvantages are factored in, it is much less than "optimal". And, antifreeze is not a "horrible" coolant

 

[SupraMario]

Coolant does in fact increase the boiling point, but the primary factor is the system is pressurized. One problem running pure water is if system pressure is lost due to a leak...instant boil over. The only advantage is water's heat transfer ability...when water's disadvantages are factored in, it is much less than "optimal".

I use distilled water, granted it still can do a number on the block, but I drive the car daily, so its not sitting...ever. I also run Redline water wetter in it, I don't know if this has any anti-corrosive additives but I've got 0 rust in the lines/rad/block.

 

[jdub]

You should always use distilled water...even when mixing up a 50/50 coolant fill.

Redline water wetter is what I would use in a 100% water system...you do not want to use it mixed with coolant. It doesn't play well with certain coolants (Toyota Red is one of them).

The point is moot for me...I would never use a 100% water fill unless it's an emergency. There is no real benefit to do so. The coolants I mentioned earlier will easily keep the 7M in it's ops temp range (assuming the cooling system is in good shape) and provide excellent protection for the system.

I've always wondered why anyone would run 100% water on a street car. They do it in race cars because that is one of the rules, but it is not "better" by any measure.
(it is cheaper though)

 

[chefma70]

Coolant does in fact increase the boiling point, but the primary factor is the system is pressurized. One problem running pure water is if system pressure is lost due to a leak...instant boil over. The only advantage is water's heat transfer ability...when water's disadvantages are factored in, it is much less than "optimal". And, antifreeze is not a "horrible" coolant

jbub thanks for the amazing advice!:icon_bigg

btw the only reason im running str8 coolant is because the main coolant hardline that runs from the waterpump under and across the turbo manifold and around the back of the block rusted. And got a hole and i had to do 6-10 hours of hard work .for now im gona go to the junkyard and pick up some electric fans for around 20 bucks.

step 1 remove turbo and manifold
step 2 disconnect all turbo lines.
step 3 helicoil exhaust studs:3d_frown:
step 4 disconnect engine and transmission brackets
step 5 lift engine 6 inches
step 6 install new used coolant line thats alot less rusty.
step 7 reinstall everything

I NEVER want to do that again.:nono:

my coolant system plans include a mishimoto radiator and 2 electric fans. with a once a year coolant filter.:naughty:

 

[SupraMario]

You should always use distilled water...even when mixing up a 50/50 coolant fill.

Redline water wetter is what I would use in a 100% water system...you do not want to use it mixed with coolant. It doesn't play well with certain coolants (Toyota Red is one of them).

The point is moot for me...I would never use a 100% water fill unless it's an emergency. There is no real benefit to do so. The coolants I mentioned earlier will easily keep the 7M in it's ops temp range (assuming the cooling system is in good shape) and provide excellent protection for the system.

I've always wondered why anyone would run 100% water on a street car. They do it in race cars because that is one of the rules, but it is not "better" by any measure.
(it is cheaper though)

I know its not needed, but I flush my system before winter and after winter. So its cheaper if I run just distilled water and water wetter, since like you stated it doesn't play well with coolants. Winter time is 50/50, summer is just %100 water and RL WW.

 

[Poodles]

I remember testing this in a lab at school years ago...

By itself, neither water or coolant is fantastic. Mixed is a different story. The 50/50 mix has a higher boiling point and lower freezing point than either one alone.

Now, outside of that, if everything is prefect and you have excess cooling capacity, you should be right about where the t-stat opens.

And electric fans aren't an upgrade...

 

[LilMissMkIII]

Great thread... I was just wondering the other day if my temps were okay (we had a couple days at 100*F).

According to the advice in here, my car is running perfect :boobies:

 

[Boosted516]

Coolant does in fact increase the boiling point, but the primary factor is the system is pressurized. One problem running pure water is if system pressure is lost due to a leak...instant boil over. The only advantage is water's heat transfer ability...when water's disadvantages are factored in, it is much less than "optimal". And, antifreeze is not a "horrible" coolant

very true, i think its 3 degrees every psi or vice versa. what are the disadvantages of water other than the possible harm it can do to the block, and low boiling/high freezing points? im not saying antifreeze is a horrible coolant, im saying by itself w/o water it is.

 

[GeneStarWindGSW]

Would it be alright to run straight Zyrex G05 (no water)?

 

[jetjock]

It never ends...

 

[GeneStarWindGSW]

It never ends...

It never does :cry:

funny though, because i use G05 on my car and my friend wanted to know if it would be alright to use on his 7m.

I just told him to go on my computer and ask :biglaugh: