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At my wits end with my a/c!

elyon

elyon

1/2 ton status
Joined
Feb 16, 2012
Posts
214
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Location
Eastern NC
I replaced my whole system a year ago. Every thing. Charged it with 134a to 80% of original R12 charge and it ran fine for most of the summer. Then the compressor seized. Replaced the compressor, condenser, accumulator and orifice tube. Flushed the hoses and evaporator. Added ester oil, charged with 134a. Ran fine for a while then started to heat up. Compressor developed a leak. Replaced the compressor. Flushed the condenser, hoses, evaporator and replaced the orifice tube. Charged with 134a. Ran great for about 30 minutes. Now starting to heat up again. I also installed a trinary switch a while back. Aux cooling fan for condenser. At all times I used a vacuum pump to draw the system down for an hour before charging.

My system uses the pancake style compressor. 1986 Suburban.

I'm lost. Any thoughts???
 
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When you say heat up, I assume you mean the air coming out is warming up. You need to find out why.
Is the compressor running? If so, then what are your pressures? It sounds like you may have an issue from the first compressor failure.

Not sure which system you have, if its an orifice tube or an expansion valve. Either one could be partially stopped up from debris from the failed compressor. Flushing will not clean out a stopped orifice tube, it has to be replaced.

First thing you need to do, is put a set of gauges on the system and see what it going on.
A blockage would cause the intermittent cooling and the compressor failures.
 
Did you replace the evap or the condenser?

Not sure how hot you're getting there as far as ambient temperatures, but I never had any real good luck with running 134a while I lived in Phoenix. It would work, and work like it was supposed to while driving down the freeway, with the constant air flow over the condenser, but once I got into city traffic with stop and go type situations, the engine driven fan, even with the heavy duty cooling fan clutch, would not cool the condenser down enough to keep the ac cold in the cabin. When this happens, the freon is returning back to the compressor hot as well and eventually overheats it.

That's why I always try to tell people, if you're converting from an old r-12 system, depending on your climate, you probably should replace the condenser for maximum efficiency.

All vehicles I have driven so far that came from the factory with 134a have cooled very nicely, even in low air flow situations because that condenser was designed, with more cooling passes, to cool the freon more efficiently.

I even went so far as to add two 12" electric fans on the front of my Burbs and it really did minimal in helping with it cooling.

When I finally broke down and bought the new condenser, cleaned & vac'd the system, the compressor gave out while refilling, too many overheat cycles I am guessing, so I gave up on the whole thing. Yup, brand new condenser in it for the past several years, never been used. :doah:
 
When I say getting hot, I mean my engine coolant temps start to rise significantly after a period of time.
 
Fan clutch comes to mind, that's only at idle and low speeds tho.
Parallel condenser for sure with A 134 conversion.
Not going to be as cool as r12 anyway IMO.
 
Try the heavy duty fan clutch, you'll get a bit more fan noise for a longer duration during first start ups, but it works awesome for any amount of towing of heating problems. Also if you're actually having engine heating issues, it's probably time for radiator service or replacement.
 
I have a heavy duty fan clutch. Installed it two years ago.

I just installed a Griffin exact fit aluminum radiator to.

If your fan clutch was going bad, how would you know? Reason I ask is, I have had for a while now a funny erratic chirping noise coming from something ancillary. At first I thought it was something rubbing on the harmonic damper, but that wasn't the case. It is not the alternator, water pump or power steering pump. Tried to track it down with my stethoscope. It seems to come and go. I was wondering if it might be the fan clutch.
 
Check the idler pulleys, I've had to change out 2 so far with mine in the 10 years I've owned it.

Do you have a complete fan shroud installed?
 
I do have a complete shroud.

The coolant temps are perfect without the A/C on. Indicating about 185 on the stock gauge at all times. When I first recharged the system yesterday, it was making cold air and the coolant temps were staying right at 185. Then after driving for a bit, the temperature started to rise to 210. Turned the A/C off, temps return to 185. My guess is the compressor is making metal and clogging the orifice tube. I can't for the life of me figure out why though. I under charged the system as recommended. Used Ester oil. Only thought I have is I purchased a higher dollar 134 a refrigerant that runs cooler than normal 134a. I am wondering if it might create to much pressure for the old style R12 pancake compressor.
 
elyon said:
I have a heavy duty fan clutch. Installed it two years ago.

I just installed a Griffin exact fit aluminum radiator to.

If your fan clutch was going bad, how would you know? Reason I ask is, I have had for a while now a funny erratic chirping noise coming from something ancillary. At first I thought it was something rubbing on the harmonic damper, but that wasn't the case. It is not the alternator, water pump or power steering pump. Tried to track it down with my stethoscope. It seems to come and go. I was wondering if it might be the fan clutch.
Click to expand...

You can try to spin your fan manually, it should not spin freely or without resistance.

As far as the a/c goes have you checked the system to see if there is blockages like with a temperature gun. How did you flush the system out originally? Sounds to me like there may be trash in the system causing the the problem. I wouldn't think your high dollar 134a would have a higher pressure than regular 134a and if so it wouldn't be much or it would say on the bottle.
 
Not sure if this is true in your case, but I know quite a few people that have had bad luck with remanufactured compressors, high failure rate. You didn't specify, but most people tend to use reman because of the cost.

How did you fill the oil? If the system has been discharged of oil (due to conversion or compressor replacement) most tutorials I have seen recommend putting half the oil charge in the suction side of the compressor, and rotating the clutch by hand a number of times to ensure the compressor is well oiled prior to startup. The other half of the oil charge typically goes in the accumulator. Inadequate oiling at startup can burn a compressor up real quick.

Sometimes you have to change out the pressure switch for one designed for R134A, since it has slightly different pressures. A retrofit switch is available.

And while 210 is a bit warmer than normal, it is far from dangerous. It's not unheard of to see higher temps if you're in a lot of stop and go traffic and the compressor is running a lot. Definitely check out your cooling system though and make sure you don't have a problem.
 
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I have yet to own a vehicle with A/C that worked for any length of time...my Ford Contour was the only car I had that it worked well on for about 4 years,then it lost its freon charge...even the '93 Caravan my dad bought new had problems with the A/C the first summer,the compressor shaft seals leaked the oil & freon out..after it was fixed under warranty,I had to add freon every summer,and if you were lucky it would work a few weeks..

I consider A/C a luxury ,up here,it does get hot and humid for maybe a month or so,but I can deal with heat and humidity a lot better than the cold,for a few weeks a year I dont mind sweating some,after freezing 6 months a year!..
--a good heater is 100% mandatory to keep the windows defrosted and you warm,A/C to me,is just an un- needed waste of money to try and keep working--and vehicles without it have more room under the hood to work on them too...if I lived in Arizona,CA,or Florida,I'm sure I'd have a different opinion though...in those places A/C is a must,just as heat is up here..
 
Is this running down the road or sitting still, temps? It's going to be hotter with the ac on. Spin your fan and see if it Spins freely or say 1 turn like was suggested.
If temps are ok when driving in motion and go up too much when stopped its an flow air problem. Recheck the Otube for metal to eliminate that.
Condenser could be dirty with bugs and such restricting airflow.
 
..doesn't 134a require PAG oil...?:whistle::whistle:
 
Ester combines with pag or mineral oil, unless you replace everything or have 2% or less mineral oil you shouldn't use pag. Plus you can go back to r12 easily.
 
Where I live A/C is a must have in summer. Everything under the hood is very clean. Condenser is completely bug and dirt free. Fan clutch checks good. I really think it is internal. Just can't figure out what I am doing wrong.

Going to check pressures on Monday.
 
Thank you for the link! I learned a bit more. One thing I learned is that I am under charged which can cause a super heat condition. Did not know that. Second is I am going to get the proper clutch cycle switch for 134a. I did not take into account the loss of refrigerant in the service lines and residual in the can. This particular web site called for a 90 percent state of charge for 134a. Most other folks call for 80 percent.

Seems GM call out is for PAG 150 for R4 compressors. I put 2 oz of Ester oil in the compressor when I installed it. When I just flushed the system (not the compressor), I didn't add more oil as it seemed to have quite a lot in it at the orifice tube. I was thinking it might have been too much. Accumulator had oil in it and the new 134a has oil in it.

I may have already damaged my compressor just the same, but it is worth a shot.
 
No problem, hope it helps. There's still a chance that the comperssor is alright, some of them will take a beating.... well atleast in residential and commercial units lol. Where in Eastern NC are you at?
 
Wake Forest area.

So I went and purchased the proper clutch cycle switch and installed it. It cycled on and off accordingly, but too frequently. I added 134a as I calculated that I was about 8 oz low based on what I read on the ac repair site and given how much 134a I had charged the system with a few days ago. All the while it is making cold air. 20 degree drop from the center vent, but now the return line to the compressor was freezing up and the switch didn't cycle off. Pressures were reading around 34/152 so I was thinking it is now over charged. Started bleeding system off a bit at the time. Last pressure reading was 29/151 35% humidity 66 degrees ambient temp. I drove the truck to the store and cycle switch was working.. Still making 40 degree air at center vent. It did not appear to freeze up the return line. Who knows what the 134a charge is at this point!

You need to go to school for this stuff!
 
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