artizen Posted February 10, 2005 Report Share Posted February 10, 2005 Anyone out there have intermittent AC outages? Here's a typical scenario: Around town:Start car, AC works fine, perfectly cold enough for a Texas summerDrive around town for around 20-25 minutes, the air gets warmIf I shut off the car, wait about 5 minutes, when I start, the AC gets cold againDriving highway:As long as the AC is working when I hit the onramp (and no traffic), the AC stays coldThe minute I hit traffic, it goes back to getting warm after around 20 minutesAll light on AC buttons are working correctly. Fan is blowing air. This happens if the air recirc button is on or off. Already spent time (3 weeks) and money ($400) at the local Volvo dealership. They could not fix the problem. This is a VERY annoying problem. Any help/suggestion would be greatly appreciated. Thanks in advance,artizen Link to comment Share on other sites More sharing options...
patrick Posted February 10, 2005 Report Share Posted February 10, 2005 taken from the excellent a/c writeup on this very site:"Very often the first sign that the system is malfunctioning is the rapid cycling of the compressor clutch because of a loss of refrigerant"loss of refrigerant, id put money on your evaporator, plus might be the most commonly failed part on these cars... unfortunately its quite $$ to replace. ask that dealership or check ur invoice to see if the evap was touched, i doubt it was for 400 dollars, since its pretty much in a steel safe behind/under the dash. (sarcasm about teh steel safe but you get the idea). Link to comment Share on other sites More sharing options...
icelandic Posted February 10, 2005 Report Share Posted February 10, 2005 Artizen,My 1994 850 with 153k miles suffered the same problem. I replaced the evaporator, checked everything and the problem continued exactly like yours.After a lot of testes and research on many different forums I finally found out what the problem was and had it corrected last week. Most probably your A/C compressor is cycling of under certain conditions because the thermal protection switch built into the compressor is telling it to cycle off because compressor temperature is too high. And why is it too high? Because due to wear, the gap between the compressor magnetic coil plate and the clutch plate has increased beyond the maximum which is 0.6mm. Under this circunstances, the magnetic field generated by the clutch coil under, is slightly weakened by the high ambient temperature, just enough to make the clutch be unable to engage. As it tries to make it engage, temperature on the compressor rises above normal and the thermal switch does its act. You may find on the forums that a solution to this problem is to override the thermal switch, which works, but will lead to a more serious failure of the clutch later on.The correct solution is to carefully remove the compressor ( no need to evacuate the system or undoing the connections) then with the compressor lowered from the frame under the car, remove the clutch plate and adjust the gap by removing one or more of the shims behind it so that proper gap is acchieved once the clutch plate is mounted back. See this:http://www.volvoclub.org.uk/dc/dcboard.php...id=11445&page=2Before you do anything, just to make sure this is your problem, Measure the gap with a feeler gauge with engine off. Then do a second test: with the car and a/c on during the occurrance of the problem, that is when the a/c stops cooling, using a large screw driver and carefully tap the center of the compressor clutch plate. Be careful of the serpentine belt and pulleys. If the clutch engages, that is the smoking gun. You found the problem.Good Luck!Luis Link to comment Share on other sites More sharing options...
artizen Posted February 10, 2005 Author Report Share Posted February 10, 2005 Thanks guys. I really appreciate the input. I'll look into the fixes you mention and report back (hopefully with success!). Link to comment Share on other sites More sharing options...
Matts 850 GLT Posted February 10, 2005 Report Share Posted February 10, 2005 Hi LuisAre you serious about tapping the compressor while the motor is running and the a/c is on??? Just seems dangerous!!Anyway thanks for the input as I have a similar problem!Matt1993 850 GLT auto 158,000 miles Link to comment Share on other sites More sharing options...
icelandic Posted February 10, 2005 Report Share Posted February 10, 2005 yes, I am. Do it in a well lit area with an adequate toll. Just tap the center of the clutch plate. Of course, before doing that, rehearse a bit with engine of, to identify the dangerous spots. Link to comment Share on other sites More sharing options...
Matts 850 GLT Posted February 10, 2005 Report Share Posted February 10, 2005 Well, I measured the gap between the clutch plate and compressor and no surprise!! I could get 0.7mm between them. This probably explains the erratic on off behaviour of the a/c.So I wil plan an a/c repair job.Did you work from under the car? Matt Link to comment Share on other sites More sharing options...
patrick Posted February 10, 2005 Report Share Posted February 10, 2005 i have a working compressor free spinning on my car right now.. if someone wants to repalce the whole unit for cheap ill sell it, it'd be motivation to hurry up and remove it. (it will be officially for sale when i get off my lazybutt and get the new belt to remove it) Link to comment Share on other sites More sharing options...
icelandic Posted February 10, 2005 Report Share Posted February 10, 2005 Matt,Yes, from under the car, splash guard off. But really I think you should try the clutch tapping act just to double check. Do it carefully, and you do not have to tapit hard.Luis Link to comment Share on other sites More sharing options...
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