air conditioning

[hornet7288]

Years ago when I swapped in my GTE motor I decided that I did not need AC. I never installed the compressor on the GTE engine and removed it from the bay after the GE was taken out. Years later I am tired of sweating everytime I take the supra out in the summer (the summer is 10/12 months here in Savannah, GA IMO). The only problem the air conditioning had before I removed it from the car was that it leaked all of the refrigerant out in about 2 weeks time after being recharged. Other than having a leak the clutch on the compressor seemed to engage fine, both cooling fans worked and as long as the system was properly charged it blew nice and cold. I now have all of the hardware that I need to mount the compressor back, but my question is where do I start? I thought about replacing all of the gaskets on the system, but never really found a diagram which indicated where gaskets are (if there are even any). Should I just put it all back together, charge it up with the UV dye stuff and try to find the leak myself? I have minimal AC experience, but would like to get it fixed. Any suggestions are great!

 

[suprarx7nut]

You'll want to replace every o-ring in the system. It's not too bad. You'll want a new drier, new expansion valve and oil and refrigerant. If you start with that basic maintenance you may solve your leak.

I converted to R134a and it's worked fantastically. I was concerned about it not blowing as cold, but it's ice cold, even in the 115F AZ heat.

There's a thread on here that helped me greatly. I haven't taken the time to document any of it myself, but the info on here was great.

 

[hornet7288]

I looked around some but didn't find a thread. I'll try to dig a little deeper. Do you know if all of these parts would be available aftermarket at an advance auto or some place like that?

Also, does almost every connection in the AC circuit have an o ring or not necessarily?

Years ago when mine was working I also converted to R134 and it felt great. Hoping to restore it soon!

 

[Suprapowaz!(2)]

Should I just put it all back together, charge it up with the UV dye stuff and try to find the leak myself?

I would do this. Rockauto has seal/gasket/o-ring kit for under $7. Just follow your lines and see where the seals/o-rings go. They also have Denso expansion valves and driers that cheap. You can rent a/c gauges and vacuum from autozone. Chances are its leaking from an o-ring.
Pour recommended amount of UV dyed oil into the compressor. Install it. Replaced expansion valve and drier and all seals and orings. Pull vacuum and see if it's holding. Add freon until compressor clutch engages and let it cycle to see if you find any UV dye seeping out anywhere. If all is good continue to add freon until the numbers on the gauges look satisfactory and it feels cold out of the vents. I'm very amateurish as this stuff, but I know the very basics to get a system cooling. I just did my Protege recently and it works good. I took and chance on buying a reman'd AC compressor from these guys http://www.jensenautoparts.com/ and all is good so far. They have good prices on compressors. I'm sure there are many other places to get a compressor from if you need one. Good luck and keep us posted on your progress.

 

[hornet7288]

That sounds good! I just removed the front upper and lower bumper and began replacing o rings today. The only two I am not sure of are the two sensors near the turbo. I am sure they have o rings but they look like they will be really hard to get to. Also had alot of trouble figuring out how to install the compressor. I am guessing I will have to go in from the top side after removing the alternator. Other than that it seems to be going smoothly.

 

[Suprapowaz!(2)]

4 bolts on the side will remove and install the compressor from the bracket. Follow TSRM procedures. Don't make it out to be more work for you. Take your time and have patience. You'll get through this.

http://www.turboninjas.com/mk3supra/

 

[hornet7288]

Yea I couldn't see the 4 bolts from all of the gunk caked on the side of the compressor haha. Once I used some purple power to make the compressor look new again I was able to see the 4 bolts. I haven't had time to mess with it yet, but i'll install the bracket first then go from there. Shouldn't be too bad.

 

[hornet7288]

I think I have previously mentioned that I'm using the same compressor. When I shook the compressor it sounded like it still had oil or fluid in it. I mounted it up to the car today. Do I need to worry about adding oil to the system since I am using the same compressor? Or can I just put vacuum on the system and charge it up using a vacuum pump and manifold gauge?

 

[Suprapowaz!(2)]

Has the old R12 system ever been converted to R134a? Do you have the R134a fittings? The old R12 systems originally used mineral compressor oil. The new Pag oil is not compatible with the mineral oil and will not mix. Ester oil will work with both R12 & R134a and is compatible with mineral oil in case there is any still left in the system. What exactly happens when mineral mixes with pag I don't know.
You can always flush a system out, install your new expansion valve and new drier and use pag. If you don't know what kind of oil is remaining in the current system then those are your two options. I think. That's my amateurish advice.

 

[hornet7288]

It was converted over to R134a by the guy that I bought the car from. I couldn't tell you whether it was properly done by completely evacuating the system and replacing it with pag oil and R134a. Also there is no way for me to tell exactly how much oil is currently in the compressor. I suppose at this point once I get it all buttoned back up my best bet is to take it to a shop to have them completely evacuate the system and fill it back properly. After watching some youtube stuff it looks like I can fill it myself, but I don't know about completely evacuating the system. If I am going to have someone else evacuate it then I might as well have them fill it too.

 

[f00g00]

If you still have the original condenser I would recommend getting a parallel flow installed. I had one installed here in Kuwait and it got rid of my overheating problems and blows cold. The tech mounted a universal one.

 

[hornet7288]

I may look into doing that f00g00.

So I ended up getting a gauge set and a vacuum pump. I was able to apply vacuum to the system and when I closed both gauges I found that I still have a small leak. It leaked all of the vacuum out within 10 or 15 minutes which was no huge surprise. So the only way I could think to find the leak was to charge the system with some UV dye. This idea was nothing short of a disaster. I was able to get the system charged enough to where the compressor was kicking on which was cool. The system would not take near the required amount of freon. Other than that I was not able to tell where the leak was and using the UV dye was such a mess I probably wouldn't be able to see the leak anyway. I was able to see that all of the o rings I replaced were not leaking. After filling it up to a point where I figured there may be enough pressure so that the UV dye may show where a leak could be I pulled everything off. The schrader valve on the low side proceeded to blow all of my freon out...awesome. So I will replace that valve and try again I suppose.

Is there any other way to check for leaks other than buying expensive freon and wasting my money knowing that it will leak out?

I am at the point now where I am pretty much about to give up. The car is not a daily so repairing the AC was a shot in the dark. It sure would be nice to have it working because it is too hot here in Savannah to drive it during the summer and actually enjoy it.

 

[bestsupraever]

Hi, first clean up the dye residue with water and dish detergent. Then if you are using r134 get a can of r134 with the dye in it. You don't need to fill the entire system. Just enough to pressurize both sides. 1-2 cans should do it. Install the refrigerant to a vacummed system. Search for the leaks with a black light. If you find no leaks in the o ring connections, after it runs a bit check the condenser with the black light with the car off. Check both sides, top and bottom , front and back. Then check the compressor especially near the connections and clutch. Then look carefully at every line rubber and steel. Finally check the evaporator, this is a bit tough, because it is buried where you can't eyeball it very well. But you can look at the condensate the comes out of it with the black light, and if the evaporator is leaking it usually shows in the condensate. The only other place to check is the expansion valve , you may need to remove a panel or two to see it.
Now if you are using R12 you install a few pounds and use a simple halite torch hose apparatus to find the leak.
Good luck.

 

[hornet7288]

Yea I am going to replace the schrader valve on the compressor again and give it another shot. I will probably look around a little before I charge it again just to see if any leaked out somewhere else

 

[hornet7288]

So I ended up messing with the low side schrader valve and what I found out was that if they R134 conversion attachment was too tight it caused the schrader valve to stay open and leak freon out. So now that I have that figured out I put some freon back in and I am waiting for it to see for a little while so I can check for leaks. I did not see any right off of the bat at any of the junctions, condenser, drier, compressor, sensors near turbo or anywhere on any of the lines. Perhaps my leak was happening at the low side shrader valve. I will try vacuuming the system to see if it will hold vacuum for half an hour or so and go from there.

 

[bestsupraever]

Yes it is possible that the valve wasn't holding. But while the guage is arrached and the valves are off, even a bad schrader shouldn't leak, the guage and hose should hold the pressure. And if you have a proper cap tightened on the schrader when all is buttoned up, that should hold the pressure even with a leaking schrader. Use metal caps with rubber seals in them. Also when looking for the leak, don't forget to use the black light, they come as battery operatd lights, for automotive use, they will make it much easier to find every leak.
When using the vacuum , use it for a good 2 or more hours to really dry the system out, make sure the hoses have good seals in the ends, and are quite tight on the fittings, vacuum from both high and low sides.
Good Luck

 

[hornet7288]

I will give that a shot. School just started back this past Monday so all of my supra projects are put on hold unless I have enough time to mess with it on the weekend. I probably do need a good vacuum pump to use that can run for that long. The pump I have utilizes my compressor to convert pressure to vacuum. I don't think I want to run my compressor for that long at one time.

 

[atmperformance]

I took out my A/C because racecar, now i'm of the feeling even racecars want A/C 7m or not

 

[Nick M]

And if you have a proper cap tightened on the schrader when all is buttoned up, that should hold the pressure even with a leaking schrader.

They do with all the gorillas that seem to work in automotive that think hand tight valves need to be tightened to 500 lb/ft. Then they say the Robinair machine is junk.

When using the vacuum , use it for a good 2 or more hours to really dry the system out

Good advice. Water vaporizes at low pressure, but it still has to pump out. Occasionally I see some manufacturers wrongly state something dumb like 15 minutes....on a system that holds 7.6 lbs. I often wondered if it was just a lack of having a technical editor. An hour on a car is good practice. Can you get away with less in Las Vegas? Probably.