QuestionHey Rocky!
I have a problem with my 4 door 2002 Golf GLS, automatic transmission, currently at ~80,000 miles with a Climatic A/C system. I first noticed a problem with my A/C as I was driving home from work at 8:30 am - going around 50mph. I usually have the A/C on all the way cold (I live in FL), but as I was driving home it was a bit chilly, so I turned the A/C level dial up a bit. From the 7 O'clock position all the way cold, to about the 9 oclock position. The air coming out was unusually hot after I turned it up, especially since the dial was still in the blue. Later, when I drove it again in the heat of the day, I noticed the A/C wasn't working at all. On the contrary, the A/C was blowing hot air at all settings at and above the 9 oclock position. At the 7 oclock position, it blew warm air similar to the temp outside (~90 degrees). I didn't have $$ to have it looked at right away, so I just drove around for a few weeks without A/C.
About a week to 2 weeks later, I'm driving around and my engine overheat light comes on. I pull over, let it cool, and turn it back on and slowly drive home. When I turned it back on I got a Check Engine Light.
So, the next day I took it to the dealer and had the 80,000 mile service and had them look at the CEL. I didn't tell them about the A/C because I thought the problems were unrelated, and didn't want to spent too much $$. They said it was a faulty "temperature sensor" and they replaced it.
That was about 2 weeks ago. Today, as I'm driving the car (with the AC on, but still warm air), the engine overheats again. I let it cool, and drive home. On the way, the temp gauge starts climbing towards the red, and I turned off the A/C. As soon as I did, the temp gauge rapidly moved towards the middle. I drove it again about 6 hours later, with the A/C off, and the temp stayed normal the entire time.
I'm about to take it back to the dealer, or another shop, and have them check out the A/C system, but I want to get your opinion before I go in. Any idea on what could be causing the A/C to overheat the engine? Could it just be a coincidence?
Thanks for any advice, you're really providing a great service here, and I can't thank you enough for your time!!
Jason
AnswerHi Jason;
Thanks for all the information about the conditions.
Sure sounds to me like your A/C compressor quit. I'll bet you still have a good charge of refrigerant, but the compressor had a failure. I think the timing, and the adjustment of the control are all coincidental. However, when the compressor quits working for whatever reason, it's usually catastrophic. It normally breaks a part inside, and sends the little pieces into the TXV...thermal expansion valve. This means a bigger than normal bill to get it fixed, because the entire system has to be backflushed with a high pressure nitrogen gas carrying detergents, or cleaners. I would, in this case highly recommend a shop that specializes in A/C work, and nothing else. They usually have an "old guy" who knows how to handle these failures, but I would call around first. Living in Florida, you should have a wide choice of shops to take it to. Make sure they are familiar with TXV systems, and not just FOT...fixed orifice tube...systems like the domestic vehicles use. Also, if they are willing to spend the time on the phone with you, ask what they would flush the system with. There are a bunch of miracle solutions out there, but high pressure nitrogen, with cleaners works best, and it DOESN'T hurt the environment...it's just nitrogen(70% of the atmosphere is nitrogen). The dealer you got the temp sensor replaced at did what they could. They were right to do what they did. The temp sensors fail...the black ones, you got a newer green one, and they work better. It's possible that when the temp sensor was removed, too much air got into the cooling system, which will require a complete cooling system flush, and an evacuated refill. there is only one way to properly refill the cooling system on Volkswagens, or Audis, and that is to evacuate the system to over 1.5 atmospheres, and then refill at that vacuum. Otherwise air pockets are left behind, and your car will overheat...all the time....even in Alaska.
