help with my '87 a/c problem

:helpme:i thought this would be the best place to seek advice so here it is.. a few years ago i converted my '87 cherokee to 134a because I had to replace the high pressure line. this summer my a/c is not cooling well. I checked my pressures with my gauges and I have around 30 psi on low and 200 on high side. also the line coming out of the expansion valve is not very cold to the touch. I don't know if maybe there's moisture in the system, I put too much oil back into it when I converted or what.. when i converted i lived in a cooler climate (prescott az, and now live in tucson az), and i am aware that with 134a conversions you loose some cooling but my system is barely cooling at all.. it's not even comfortable

does anybody know the proper steps to charging this system with 134a? I guess i am going to drain down the system, drain all oil from compressor, vaccum and re-charge it.. maybe replace the expansion valve.. how much freon should I use, oil and etc? any help would really help me out.:helpme:

Sounds like the compressor is failing.. My 87 did the same thing after I switched it over to 134a..

Nick

What was the ambient temperature when you had 30/200?

If it was 95 F or higher then you are low on R-134a. Mine got up to 45/325 the other day with a 100 F ambient, then dropped to about 35/270 once the inside had cooled down and reached equilibrium.

Try adding a can of R-134a.

well I guess it was about 102 out when I had the gauges on it. 45/325 seems pretty high.. i don't have much experience with a/c though.

Ecomike said:

What was the ambient temperature when you had 30/200?

If it was 95 F or higher then you are low on R-134a. Mine got up to 45/325 the other day with a 100 F ambient, then dropped to about 35/270 once the inside had cooled down and reached equilibrium.

Try adding a can of R-134a.

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Try quick easy first. Add a can like Ecomike says. Many systems loose a little every year and just need a little touch-up with "freon" once in a while.

winterbeater said:

Try quick easy first. Add a can like Ecomike says. Many systems loose a little every year and just need a little touch-up with "freon" once in a while.

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The newer QC o'ring seals are notorious for drying up, shrinking during the winter, or layups, and letting the newer R-134a leak out around those QC seals, at about a 12 oz can rate during the off/cooler season.

30/200 is too low. If it's been several years since the last fill, you have have an acceptable leak. If sooner, you should check and correct any leaks.

Did you change the dryer when you did the conversion? If not, now would be a good time. Don't forget to add fresh oil first. I got my stuff from www.ackits.com

R-134a is filled by weight. My '88 FSM says 36 oz of R-12. R-134a is generally 80%. 7oz of oil in the compressor, 1oz in the dryer.

Saudade said:

30/200 is too low. If it's been several years since the last fill, you have have an acceptable leak. If sooner, you should check and correct any leaks.

Did you change the dryer when you did the conversion? If not, now would be a good time. Don't forget to add fresh oil first. I got my stuff from www.ackits.com

R-134a is filled by weight. My '88 FSM says 36 oz of R-12. R-134a is generally 80%. 7oz of oil in the compressor, 1oz in the dryer.

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I think you may be confusing him a little with that post. He has 30/200, in 102 F ambient, several years after a successful conversion to R-134a, so it seems reasonable that the leak is minimal, and typical of R-134a in a 21 year old jeep, so all he should need to do is add 1, 12 oz can of R-134a, at the most. I see need to add oil, etc. Changing the dryer now would require draining the system.

Ecomike said:

I think you may be confusing him a little with that post. He has 30/200, in 102 F ambient, several years after a successful conversion to R-134a, so it seems reasonable that the leak is minimal, and typical of R-134a in a 21 year old jeep, so all he should need to do is add 1, 12 oz can of R-134a, at the most. I see need to add oil, etc. Changing the dryer now would require draining the system.

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In the interest of clarity, do you mean "I see NO need to add oil, etc."?

Ecomike said:

I think you may be confusing him a little with that post. He has 30/200, in 102 F ambient, several years after a successful conversion to R-134a, so it seems reasonable that the leak is minimal, and typical of R-134a in a 21 year old jeep, so all he should need to do is add 1, 12 oz can of R-134a, at the most. I see need to add oil, etc. Changing the dryer now would require draining the system.

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He said it was several years since he changed over. He has said nothing about not adding any refrigerant since. That why I said both.

He also said he may discharge the system anyway.

winterbeater said:

In the interest of clarity, do you mean "I see NO need to add oil, etc."?

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Ah the missing negative "NO", thanks good catch. Yes I meant "NO", er, I mean I see NO need to to add oil, change the dryer, at this time. If he had added R-134a again since the change to R-134a, I suspect he would mentioned the continuing losses, but now that I reread his first post I see Saudad's point.

My thought was it sounded like he was about to jump off the cliff, when all he needed was a can of R-134a. I assumed that if he made the change several years ago, it must have worked until recently, so why start over.

He sounds like the type who would jump in change a bunch of parts, and do a bunch of work with out first figuring out what was wrong, and I was afraid Saudade was about to encourage that approach.

Long story short, we probably need feed back from the OP as to what the total history is here.

After a couple months of not using my jeep, I jumped in it and got no cold air. Went to autozone today and got two 14oz cans of "Artic Freeze" (they came together) It has a cheap gauge included. Hooked it up to the low side and got a reading of 20-25. At 100 degrees the instructions say it should read 45-55. I dumped 1 can into it and that brought it up to 45. Cools good now! I'll save the other can for next year!

I evacuated the system and pulled about 1oz of oil from the compressor because when I originally converted it I'm pretty sure I added too much oil. I had a 30lb bottle of 134a so I charged it with my gauges until my pressure was around 300 and it's blowing a chilly 47 degress at idle (with a 103 degree temp outside) The whole reason I was skeptical about adding more freon is because I didn't know what the pressures were supposed to be. for some reason i thought 300-325 would be too high and I didn't want to blow a line.

I had replaced the dryer when I converted but this time I didn't have the extra cash, I just ran a vaccum on the system for about 30 min prior to re-charging.

I really appreciate the help and info on the pressures and such. I obviously have a minimal leak but I can deal with adding every few years.