INTERMITTENT A/C BEHAVIOR???
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Instructor
Joined: Nov 2020
Posts: 146
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INTERMITTENT A/C BEHAVIOR???
SO IM TRYING TO GET THE AC WORKING ON MY 86 944NA. thanks for all the help so far guys!
heres where im at:
replaced condenser, dryer, orings, pressure switch, and hoses. vacuum pumped evacuated. holds -30psi. 4 oz ester oil, 24oz r134 filled. low pressure side about 25 psi when running ac on at 70*f. . equals out at about 75 psi w car shut off. no leaks according to sniffer
HERES THE ISSUE IM HAVING
when i turn ac on its blowing wonderfully cold air. lasts for about 30 minutes then if i shut the car off and restart minutes later i no longer have cold. sometimes an hour later its cold air again. sometimes its the next day.
last night it went warm after 10 mins. i hit the defrost button for about 10 seconds and then i had my cold back again. tried this today after i lost cold and it didnt work. doesnt seem to be any rhyme or reason to it.
Im thinking expansion valve. any thoughts?
heres where im at:
replaced condenser, dryer, orings, pressure switch, and hoses. vacuum pumped evacuated. holds -30psi. 4 oz ester oil, 24oz r134 filled. low pressure side about 25 psi when running ac on at 70*f. . equals out at about 75 psi w car shut off. no leaks according to sniffer
HERES THE ISSUE IM HAVING
when i turn ac on its blowing wonderfully cold air. lasts for about 30 minutes then if i shut the car off and restart minutes later i no longer have cold. sometimes an hour later its cold air again. sometimes its the next day.
last night it went warm after 10 mins. i hit the defrost button for about 10 seconds and then i had my cold back again. tried this today after i lost cold and it didnt work. doesnt seem to be any rhyme or reason to it.
Im thinking expansion valve. any thoughts?
Last edited by neversinksmith; Sep 17, 2021 at 10:48 PM.
Rennlist Member
Joined: Apr 2011
Posts: 3,602
Likes: 176
From: Elizabethton,TN
Good thinking. Probably the sensing bulb that rests in the evaporator has come loose and is not reading the exit air temp correctly...OR it's lost it's charge and the entire expansion valve assy needs to be changed out. I don't know what type of material that is inside the sensing bulb, to make the bellows on the expansion valve operate. It's also possible that the needle valve inside the expansion valve is stuck. Time for a change out and be done with it. Some expansion valves (in the past) used to have an adjustment to reset and "trim" the exit air temp by adjusting the needle valve, while in operation. Dunno about the Porsche units....
