Overheating issues

[CyFi6]

Ah, I see. Only things I would be comfortable with flushing out myself are the actual lines. All I have is compressed air and solvent, not too confident that I could get all of it out of the heat exchangers, especially the condenser. If that condenser has to come out again, trust me, a new one is going in (pulled it to get flushed last time, was a treat). I will inspect the TXV, if I see any kind of contamination near the inlet, I will definitely get the system professionally flushed (again). Making a fairly long trip with the car early next month so I really need the system working soon, I only wish I would have done all this earlier.

 

[jetjock]

Flushing the lines is good. You want to get rid of anything that may have clogged something and may do so again. A busted desiccant bag in the R/D or something from an earlier compressor blow up for example.

Solvent and air is fine. Just be sure everything is dry and pull a good vacuum on the system prior to charging. I typically re-flush with IPA after the solvent flush.

I hear you on the condenser. If it were me I'd be tempted to rebuild the entire system but that's just because I wouldn't want to ever screw with it again. Probably not needed in this case though. Don't forget to add oil if you do flush the exchangers...

 

[Nick M]

I have used a commercial Castrol flush kit. It came with aluminum bottles of the solvent and adapters to pressurize the fluid. This was used for "field repairs", and I suppose your driveway if you know what to do. You will also need a vacuum pump. The pump alone saves thousands over a new A/C machine. Or you can do everything replacement wise, then take it to a shop to put it in vacuum before charging.

 

[CyFi6]

What do you guys say about charging at home with single cans of refrigerant? Is it possible to get a precise amount of refrigerant into the system? That would be the only reason I would have a shop charge it. I rented a Mastercool vacuum pump so I can pull a deep long vacuum and check for leaks on my own.

 

[jetjock]

You can charge by weight and get it close. Charging by superheat gets closer or, since it's a TXV system, you can charge by subcooling and get it dead on. That said simply putting in the proper number of cans (use the weight on the can) and topping off until there's no bubbles should be good enough.

It's your call whether to charge with vapor, liquid, or a combination of both but if you've not done this kind of thing much you should use vapor. Make sure to purge the yellow hose and if there's not already refrigerant in the gage set use the pump on it first.

 

[CyFi6]

Thanks for the tips JJ. I have charged a couple systems before but no telling if I did it 100% properly (don't worry, only on my own vehicles). One thing I never quite understood about charging with pressure, superheat or subcool is how you can get the right amount in with just these readings. Wont varying conditions ie. ambient temp, humidity, fan speed, engine speed etc all have an effect on these numbers? That's why I always thought weight was the best method because it is constant regardless of changing conditions, not to mention Toyota does not supply any specs for superheat or subcooling.

 

[jetjock]

Just go by weight and tweak it for no bubbles or coldest suction line/vent temp. Superheat and subcooling are useful for diagnosing but for charging they work best on stationary systems.

As amusing as this guy was (gotta love the photo) his procedure is adequate:

http://www.supramania.com/forums/sh...oning-system-at-home.&highlight=AC+recharging

Or use the TSRM. The main thing is no cheating. AC is like painting: the prep work is what matters. A clean and tight system with uncontaminated refrigerant and oil in the right amounts is what you want. That and proper airflow through clean exchangers.

If you do a solvent flush and can't find IPA (drugstore rubbing alcohol has a crap load of water in it) you can use acetone or mineral spirits (paint thinner) as the final flush. Just be aware if you breathe too much of that stuff your dick may fall off...

 

[CyFi6]

Lol oh yeah I remember reading that article a while back, some good info in there.
I will do that assuming I can get my hands on some R12. Is R12 still available over the counter through any stores or am I better off getting it from a private seller? I have my 609 cert so that is not an issue.

When you talk about IPA you are referring to isopropyl alcohol right? Are you talking about 100% stuff? I have a bottle of the drugstore stuff but it is 91%. I've lost a few brain cells already to that acetone stuff...not planning on losing a dick though lol

About the flushing... I plan to flush all the lines and the evap, but not the condenser (still not comfortable flushing it in place, I DO NOT want to trash my very new compressor because of leftover solvent). The only oil remaning in the system will be whatever is in the condenser and whatever is in the compressor. What about oil traces/puddling in the lines themselves, there is no mention of adding makeup oil for this in the TSRM.
Basically after flushing the lines, evap, and replacing the receiver I would be adding...
.7 oz for reciever
1.4-1.7 oz for evap

And that is it? Is this enough oil to replenish all that was removed from flushing?
Thanks.

 

[jetjock]

Yeah, IPA is isopropanol but that 91% stuff will do.

Highly doubtful you'll find small cans of 12 retail. Most places even quit carrying the 30s. If all else fails there's ebay. Best to get an extra can just in case. Also gonna need a top tap.

Oil sounds about right. Better to go a bit more than not. Make sure it's new or from a tightly sealed container. Stuff is hygroscopic. For the same reason keep the new R/D sealed in its packaging until just before installing it.

Buy new O rings. The R/D should come with some but you may need them in other places. HNBR as used with R134 is ok. Any car store should have them. If not get OEM.

After leak checking evac that puppy at least 45 minutes and don't let air get into anything. If you must, warm the first can in hot water to get enough in there to start the compressor.

And remember, careful with the red knob...

 

[CyFi6]

Pulled the system apart today to flush, flushed the lines and evaporator, but noticed the oil seemed very slightly discolored, I found a little bit of gray residue in the TXV, which concerned me. After some thinking, I decided to go ahead and splurge on a PF condenser and a new evaporator core (not sure if mine is restricted or not, but the fins could definitely be better). It is a 4 seasons aftermarket EVAP, so I am a little concerned about fitment, but if nothing else, my original will go back in. I flushed the lines, but now I will pull the compressor and flush it with mineral oil just to be sure. So in all..
New parallel flow condenser direct fit
New evap
New drier OEM
New TXV OEM
Flush lines, replace seals
Flush compressor
Evacuate and leak check, and charge dry system with fresh oil/R12. Now, all of this needs to be done in about two weeks, as long as I can get all my parts withing about a week to week and a half I should be fine, otherwise its going to be a hot 9 hour trip!

Just drained the oil out of my compressor and it appears to be very clean! :icon_razz Still going to rinse it with oil before putting it back in just to be safe.

 

[CyFi6]

I noticed that there is no add oil amount for the compressor in the TSRM, can anyone verify the full system oil charge amount?
Receiver: .7 oz
Condenser: 1.4-1.7 oz
Evaporator: 1.4-1.7 oz
Total oil amount for dry system: 3.5-4.1 oz

Then if I look at this chart for the Supra...
8.8 oz Mineral oil capacity
http://www.autoacforum.com/speclisting.pdf

That is a very large difference, any help on this?

 

[jetjock]

TRSM shows compressor oil charge is 80 cc (2.7 fl oz) +/- 20 cc.

Your amounts for when components are replaced. Adding them together does not equal total required for a dry system. You're not accounting for what remains in the compressor where most of the oil stays.

 

[CyFi6]

Where did you find that info JJ? I looked through the whole AC section and the only things relating to oil amounts are what I posted. How do I figure out what amount I need to add if I am starting from a completely dry system?

 

[jetjock]

Where did you look, on Cygnus? If so that's the problem. Buy a real TSRM.

If the compressor takes 2.7 and the other amounts need to be added should those parts be replaced is it not clear what the total should be? Sleep through math class did we? :icon_razz

 

[CyFi6]

Lol well in your last post you clearly said the amounts cannot be added together to get the total system amount, but I probably misunderstood. I know my total was missing the compressor amount, but that's why I even asked, because the online tsrm does not show any amount for the compressor, in fact they don't say to add any oil when replacing or repairing the compressor. So total system amount is about 6.8 oz correct? Oil amount that remained in the lines themselves is disregarded? What is incomplete about the cygnus tsrm, seems to have every page. Do the oil amounts that I posted earlier match your tsrm?
Thanks

 

[jetjock]

Yes, the amounts match but later TSRMs left stuff out. Complete compressor rebuilding instructions for example among other things. In your case I'd suggest an 87 manual.

We need to define "dry system". Does it include a dry compressor? If not, and everything else has been flushed/replaced, add the amounts you posted. However if it were me I'd drain the compressor, flush it with the oil I was going to use, then fill with the total (7 oz or so).

That way you're starting with all new oil and a known amount. Think about it: since the oil's sole purpose is to lube the compressor why would you leave old stuff in there? Would you change the oil only in your engine's filter without dumping the sump where most of it resides? Of course not. Remember, do it right and you'll do it it once.

 

[CyFi6]

Ok thanks, I think the 87 tsrm is floating around the net somewhere. You might have missed post #130 but I mentioned there that the compressor was to be rinsed with mineral oil etc. Pulled the compressor last night, drained it, rinsed it with fresh mineral oil, drained it and just threw it back on the car. I am going to fill it with 7 oz of oil once the system is back together and ready for evacuation so the oil doesn't absorb any moisture in the time being. The system will be completely dry so it needs the full amount of oil. God it sucks working in the heat though, my garage floats right around 100 to 110 degrees and is in direct sunlight

 

[jetjock]

I can see how that chart is misleading. "All oil specifications assume that A/C system has been properly cleaned, and new accumulator/filter drier has been installed." It then goes on to state: "Specs are for total system capacities"

For AC capacity means everything (just like does for refrigerant) therefore "total" capacity is redundant. It's no different than if we were talking about the cooling system.

As a general rule R12 systems require 6-10 oz of oil depending on size but something is bugging me. Hold off until I check it out...

 

[jetjock]

Ok, never mind. 7 oz (fluid oz mind you) if everything has been flushed. Subtract from that whatever hasn't. You didn't replace the condenser right?

That's quite the thread you have on the ac forum. No wonder you're frustrated...

 

[CyFi6]

Thanks for clearing that up. The condenser is being replaced with a parallel flow. Evaporator is also being replaced if I can get the proper evap core for my vehicle (proving to be a slight challenge right now). Toyota has so many differences between years as far as Supra AC parts are concerned, and so many have been discontinued.

So you saw my thread on there huh? Lol it is very frustrating, but I am confident I will have the system up to its best soon here.