Thursday, June 18, 2009

Short Blog about A/C (follow up to yesterday's article)

Just wanted to say, I spent some time helping someone (pro-bono work) troubleshoot their A/C system on a 97 Grand-AM. I know, I know, a Pontiac? Well, at least I don't have to drive it. The lady has been through all last summer in the AL with no A/C, and it is super hot already this summer. I just HAD to help her get it working. What is so bad, she had it "professionally" serviced last year in May. She spent over $100 getting it filled and checked for leaks. The shop said it was good to go with no leaks. Within 4 hours of working on it, she had no cold air once again. She got the run-around and they opted not to help her and she didn't have the money to fight it, nor to get it fixed. Here is a short run-down of my findings in the hopes it may help one of you.

When I looked at the compressor with the A/C on full blast I noticed the compressor didn't turn. The question was, why wasn't it turning. I figured it was too low on R-134a for the compressor to run (it had to be that or the voltage switch was bad) and decided to spend $8 on a can of R-134a. After digging around to find the low pressure cap, which on this car was way down low between the firewall and the worthless Pontiac 4 banger motor just close enough to the manifold so I had to burn my hands, I added the can. It went in very fast and almost instantly the compressor kicked in and the air from the vents was cold. It needed another can, but since I wasn't sure it wouldn't all leak out, I opted to save her the additional $8. After seeing the compressor would indeed turn, I decided to add some UV dye and see if I can isolate a leak. It is real common for them to leak around the pulley on the compressor so I hope it is that easy. All this took me a whopping 15 minutes. I did not have time to check for leaks with the light and special glasses, but I will next week and update this article.

Just wanted you all to realize no matter if it is a BMW or a Pontiac, troubleshooting an A/C system is NOT rocket science. I have never even popped the hood of a Pontiac in my life, yet the concept is the same on all cars so it made it very easy to pinpoint the issue. I am excited that this lady will have ice cold air for less than 15% of what the indy shop quoted her!


  1. Thanks Smolck! Also for your non-car talk the other day. A/C question for you: If the low-side pressure stays high (over 75 in my case) with the compressor visibly turning(!) and the A/C on high, does that likely mean the compressor has gone bad? Thanks so much (BTW, the 75 or so was the same with the car and A/C running as it was with everything shut off - no difference.

  2. Likely your suction side of your compressor is not working. I would suspect the compressor is bad like you said.

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