legacee123 Posted August 17, 2015 Share Posted August 17, 2015 Hi everyone, I was wondering if I could have some help with my 97 legacy wagon (AWD, 5-speed, flat 4cyl). I have recently run into some ac issues and my first thought was to charge up the ac with some R134a. Though it did need refrigerant, that wasn't the real problem. This problem only occurs when I am highway driving. After driving at 70mph for more than 15 minutes, the temp gauge on my dashboard starts climbing. Not to dangerous levels, but just enough so that once the temperature reaches a certain point, the ac stops blowing cold air. The problem does not occur at all when I drive below 60mph. When the ac stops blowing cold air, I can slow down to about 55, the temp gauge goes down, and the cold air blows in again. Can anyone think of reasons that my ac is doing this? Thanks, legacee123 Link to comment Share on other sites More sharing options...
subieadam Posted August 17, 2015 Share Posted August 17, 2015 How many miles on the car? Possible your head gaskets are starting to go, and the car is overheating. Also check to see if your secondary engine cooling fan is turning on with the a/c. Link to comment Share on other sites More sharing options...
Brackets Posted August 18, 2015 Share Posted August 18, 2015 Also check to see if your secondary engine cooling fan is turning on with the a/c. That was my first thought too. Link to comment Share on other sites More sharing options...
legacee123 Posted August 18, 2015 Author Share Posted August 18, 2015 180,000 miles on the vehicle. The secondary fan runs, but I can only tell that it does run when I'm standing there with the hood up and looking down into the engine. Link to comment Share on other sites More sharing options...
subieadam Posted August 18, 2015 Share Posted August 18, 2015 Hmm im not sure then. Maybe the thermostat is sticking and not letting the coolant circulate. Link to comment Share on other sites More sharing options...
twisty Posted August 20, 2015 Share Posted August 20, 2015 can you see through the condenser? i had a similar problem long ago with my old impala, turned out the condenser and rad were so mucked up i wasnt getting enough air flow through them to keep either system (cooling and ac) cold. took both out, sprayed them at self serve car wash and all good. it had so many bug skeletons in it, i was surprised it didnt overheat as soon as i started that car. Link to comment Share on other sites More sharing options...
subytech1 Posted August 28, 2015 Share Posted August 28, 2015 Your cars engine will obviously get its hottest at freeway speeds, being an auto tech, I would assume that your radiator is getting hot enough to cause the condenser pressures to increase to the point that your pressure cycling switch kicks in and shuts the compressor down. At this point, if this is the case, then your A/C system is functioning as designed. Most likely, if you correct the slight overheating issue, you could also correct the freeway speed A/C concern as well. I hope this info helps! Link to comment Share on other sites More sharing options...
legacee123 Posted September 22, 2015 Author Share Posted September 22, 2015 I took my alternator core out and it didn't pass the tests that they ran at my AutoZone. I replaced the alternator and the problems with my AC are gone. The cooling fan was fine, but my compressor clutch was not turning on and off properly. After I replaced the alternator, I could physically feel the slight difference in performance as my AC cycled on and off. Thanks for all of the help everyone! Link to comment Share on other sites More sharing options...
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