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92 Celica Still won't cool properly

jgcox6 on Tue October 16, 2007 8:12 AM User is offline

Year: 1992
Make: toyota
Model: celica
Engine Size: 1.6l
Refrigerant Type: 134 convert
Ambient Temp: 82
Pressure Low: 23-26
Pressure High: 180-200
Country of Origin: United States

Just evacuated, vacuumed down twice (30 min vac, 15 min off and then repeated), recharged system with about 20.2oz and still not very cool. As I approached the 70% of charge required,,,I added about 1.0 0z after that and checked vent temp until I approached the 80% ..which only reached about 48 degrees. Originally when I started all of this, I did have a leak at the compressor where the hoses connect and I replaced the o rings and used Nlog and closed everything up. Is it possible that the expansion valve is malfunctioning? Any suggestions....

bohica2xo on Tue October 16, 2007 11:08 AM User is offline

So what is "cooling properly" with a conversion? You can't expect the R12 specs from the factory manual. 48f vents actually sounds ok.

Your TXV appears to be working. Your high side is within the expected range, if that is a 2000 rpm reading. If the figures you posted were taken at idle, please retest @ 2000 engine rpm, and post the results.

Take the car for a drive. Check the vent temps while moving at 45+ mph, and at least 2000 engine rpm.

The maximum load test (taken @ 2000 rpm, cabin fan on highest speed, doors open) will tell you how well the condensor is working.

Vent temps can be misleading. A good volume of 48f air will cool things down quickly - better than a trickle of 36f air. Measuring vent temps should be done with a stick type thermometer at least 4 inches inside the vent. Non-contact or "laser" thermometers are notorious for giving false air temperature readings in this situation.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

jgcox6 on Tue October 16, 2007 1:27 PM User is offline

thanks for the reply...as for the conversion cooling...this car was the first one that I have done (done more since)..and this thing would freeze you out! Well since last night..my air vent temp has gone to 60! I am sure I must have a leak somewhere. I did the vacuum and it didn't "leak" at the time. I am suspicious of my high side hose...that is where all of this kinda started. It had leaked out from the original retro. It appeared to be a slow leak at first...the dye was on the hoses out of the compressor, and it worked for months. I cleaned the hoses at the compressor and then vacuumed and charge like I spoke about earlier. I am going to check the gauges when I get off work today and will let ya know what I see. Thank you for your time and expertise... I normally do Electronics for a living..guess I should stick to that type of work

Oh by the way..i did check the gauges at 2000rpm...and was almost good enough...but like I said it is now at 60 with an outside temp of 78! I have the stick thermometer...I also have a brand new vacuum pump...that will suck the paint off the car

bohica2xo on Tue October 16, 2007 2:38 PM User is offline

Try to keep the paint out of the vacuum pump, it will not require as many oil changes...

Good job testing @ 2000 rpm. That is one of the uphill battles here - weak data. If you had those pressures before things got worse, your refrigerant loop was doing well. Something was getting cold @ 25 psi on the low side.

Check the pressures again, and see if you still have a charge on board. Once you get things sealed up & charged, start looking for a reheating problem if you don't see the performance you once had.

Many conversions don't cool as well as the R12 did for various reasons. Since yours did before I can see why your expectations are higher.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Tue October 16, 2007 4:06 PM User is offline

Well you still have a sight glass, can run the engine at 2,000 rpm, door open, AC on, blower at max, on a 80*+F day and learn how much foam you are pumping into the expansion valve. Been my experience these systems don't cool worth crap even being low 3-4 ounces of R-12.

If you have foam, can try inching up the amount of R-134a while watching the high side gauge to learn if it is even possible to clear up the glass at the conditions listed above without blowing the cork. If the high side gets much above 250 psi at 85*F, better start thinking of switching to a parallel flow condenser to see if that helps any. Course could always go back to R-12, that seems to work.

Are you being a good boy by converting since R-134a is the reason why we have global warming? And since Gore fixed the hole in the ozone layer, could 20 ounces of R-12 puncture it again? Good questions, with no good answers.

jgcox6 on Wed October 17, 2007 8:23 AM User is offline

Well...I think I found the worst part of my leak..the high side schrader valve was leaking. I went ahead and replace both the high and the low side. Vacuumed, recharged and according to the ol stick thermometer...it was reading 40 degrees! I checked the pressures last night @ 2000 rpm and low side was 26-27 and high side 220-225 with a outside temp of about 78. When I woke up this morning, and ran the air..it was freaking cold as ice! The temp on the stick still 40 degrees! I will see if it leaks off...it is already better because it made it through the night. I will keep you posted if it last.

Nick..answer to your questions...I didn't get to read your message until after I actually did the recharge, so I didn't really pay attention to the sight glass. My current system on this car actually worked great cooling prior to it leak off. Toyota did a great job with this one. I did the convert because I don't have a license for AC work, and honestly am cheap! I am not a tree hugger..and not sure that I buy into the ozone crap anyway! Who is checking the folks that say this anyway.. Thanks for your input..I really appreciate everyone taking time out of their day to help folks..GREAT JOB!

NickD on Wed October 17, 2007 8:43 AM User is offline

Bohica suggested the leak, just thought I would throw in the sight glass, but since you verified you had a leak, also sure that you had lots of foam. Would be interesting now that you are satisfied to post back what you see in the sight glass at the conditions specified.

I am a tree hugger and not ashamed to admit it, but I don't like BS and plenty of that floating around. Not really a license, but a certificate that anyone that can read or write at the fifth grade level can pass to be able to purchase R-12, there was a link around here someplace, open book test, takes about 30 minutes. Not even written by the EPA, but by 3rd party vendors, believe there are 3 or 4 that give the test.

jgcox6 on Wed October 17, 2007 3:45 PM User is offline

I will check the sight glass just to check to see what it looks like with a full charge. Meanwhile,, you have my interest peaked with the certificate...how do I go about getting one...someone got the link for it? Like an A/C license/certificate.

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