a/c problems! new to a/c repairing! does this look right to you?

[1hicj7]

I've been in the automotive business for a bit, but never done much a/c repair. I felt comfortable enough with my a/c theory to dive in to compressor replacement. I did a lot of research, got all the equipment, and did the replacement. Now that its hot outside, I'm not too impressed with the results. I'm getting, with an outside temp of 100 degrees, 80 degrees vent temp. The pressures are 110 psi with the car off, and 40 psi low side car running and 310 psi high side car running. Am I doing something wrong? new compressor, hoses (all), flushed system, replaced orifice tube, and vacuumed the system down (it held vacuum) prior to charging. PLEASE! Your help is greatly appreciated!

 

[mehedgec]

I've been in the automotive business for a bit, but never done much a/c repair. I felt comfortable enough with my a/c theory to dive in to compressor replacement. I did a lot of research, got all the equipment, and did the replacement. Now that its hot outside, I'm not too impressed with the results. I'm getting, with an outside temp of 100 degrees, 80 degrees vent temp. The pressures are 110 psi with the car off, and 40 psi low side car running and 310 psi high side car running. Am I doing something wrong? new compressor, hoses (all), flushed system, replaced orifice tube, and vacuumed the system down (it held vacuum) prior to charging. PLEASE! Your help is greatly appreciated!

New accumulator? Did you flush the system out? If you had the black death, there could be alot of nasty stuff still in there blocking up your orifice tube and condenser.

 

[1hicj7]

a/c problems!

Yes, I did replace the accumulator. I flushed the evap and condensor completely (at least i think I did). The old orifice tube was pretty gunked up! I could go in and recheck the orifice tube to see if its picked up any more debris or gunk.

 

[something9000]

i would check the temp control maybe its not opening the evap side or is stuck half way so your cold air is getting heat in it from the heater core

 

[1hicj7]

A/C Problems

Thanks for the suggestion! I'll check that out tonight. I am going to check the orifice tube. I went ahead and ordered a heavy duty automatically adjusting orifice tube. Its about 10x as much $ as a regular one, but it might help.

 

[swetrid]

Pressures seem right for outside temperature so i dont think it is really ac issue. Early explorers have heater control valve to block coolant flow with ac on, if it doesnt work ac temps will be high. Could be cable issue for temp control also.

 

[1hicj7]

a/c problems

Thanks! I'll check and see if its not a heat problem instead of an a/c problem!

 

[DaExplorer]

Is the Accumulator getting nice and cold? If so I would then check on the blend door not working. Just a thought as it sounds like you did everything right.

 

[joecrna]

Pressures seem perfect. Temp drop at center vent should be more than 20 degrees. This is often a problem out at the condensor, damage fins, bad fan or missing shroud, something that restricts air flow through the condensor or possibly heat transfer from the radiator. Is the engine running a little hot?

 

[1hicj7]

a/c problems!

@DaExplorer - Im going to go check the accumulator right now. I also just got done reading up on how to check the blend door adjustment and actuation. That is something I havent checked.

@joecrna- I was starting to wonder about the condensor... I ALMOST replaced it. It was a difficult item to flush as both the inlet and outlet are high. If i do end up going in again to replace the orifice tube (i went ahead and bought two cans of R-134 and a heavy duty auto adjusting orifice tube) a might go thru the effort of actually removing the condensor and flushing it.
Are you actually a CRNA? I wanted to do that...

 

[1hicj7]

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[1hicj7]

a/c problems (still)

OK, so I checked the blend door actuation and vent selection stuff and feel comfortable that its working correctly. I started the car and turned on the a/c to check the temp of the accumulator. when running, the outlet of the evaporator going to the accumulator was cool, but certainly not cold. I've seen accumulators that you could scrape a snow cone off of when working! Even on a hot day! I am getting water dripping out of the evap drain down on to the ground. Still not happy with the vent temp!

 

[joecrna]

Yes I am. Build cars and race anything with an engine for hobbies. I noticed you have a 1991, and mentioned having R134a. Did you already do a conversion from R12? You said the orfice tube was "gunked up". It should never have anything in it unless it was imporperly serviced before. Suggesting the "Black Death". The lube in R134 and R12 are not compatible and form the sludge often ruining everything in the system.

A couple more thoughts. If the system is ever opened or leaks enough to loose its entire charge, you must replace the dryer/receiver/accumulator (all interchangable names). If not a very early demise for the entire system, do to moisture, is just around the corner. Second, during a conversion, many people do not replace all of the parts but rather flush them. This is usually the cause of the Black Death. They are really difficult to completly flush. Especially the condensor and evaporator. Finally, an R12 design will loose efficiency when converted to R134. How much is entirely dependent on the specifics of the design of each particular system. Some are fine, many are not. Remember, the entire conversion process is controversial. Many say just flush and refill and the performance is just fine.

If you were unfortunate enough to have experienced the black death, every single component in the system including hoses must be replaced. If its is still all R12, you or anyone else never added R134, do not despair.

R12 is still available and will be for a long time. You do need a special permit to handle it but it only costs like $20. Search the internet to find how to obtain the form for the permit. You will then be able to buy in bulk from local wholesalers or in cans on the internet. You can even check the EPA's sight, the restrictions are totally overblown by AC service shops. Hey, we all need to make a living. You can use the same equipement, for the most part, as long as you keep what you vacuum out completly seperate. Its what I do. Now ask me why a hobbiest has all this in his garage, that's a completly different story.

 

[1hicj7]

a/c problems...

@ joecrna- Thanks for the advice! I did replace the hoses and the accumulator. The only things I DIDN'T replace were the condenser and the evaporator. I was going to go in and recheck the orifice tube, but then i found a really good deal on a replacement condenser on Ebay. So, im going to wait til it shows up to open the system.
I didnt even think to look for R12. I guess my only concern would then be the fact that I have the system filled with PAG100. While I'm waiting for the condenser, I might look online for some R12.

Thanks again!