[southpole1989]

hi, my a/c is blowing cold air again.(2 months ago i had it inspected and they said all is fine but it needed r134a) any way yesterday i went to turn on the a/c and it was blowing warm air. and then i noticed that sometimes the clutch would engage and other times it wouldn't and then also i noticed that the line going into the cabin from the firewall was warm not cold like my haynes book says it would be. i bought some r134a with uv dye and tomorrow i plan on putting it in. but i am wondering if low r134a would cause the clutch to only sometimes engage and also i get a weird noise coming from the ac vents like gas is expanding type noise. what would cause that? any help would be apprenticed thank you. and also i did think about the thermo amplifier sensor being the cause but i figured that couldnt cause the weird noises and the clutch to not always engaging.

 

[Alec]

isn't it supposed to be cold considering it is ac

 

[joefrontier2]

Here in Michigan at this time who needs AC? Just roll down the window!

 

[Mandangalo]

isn't it supposed to be cold considering it is ac

x2

 

[RBOWWOW]

my 2C
Only warning is that if you use any refrigerant...make sure there is NO sealent in it. I spent a few hundred bucks getiing my Altima put right after I tried to be the shade tree mechanic and install the R134 myself. The can I got didnt show the sealent in big type like some others so I assumed it didnt. Anyway, the other issue I had was similiar to yours. Compressor cycled on/off. Shop said that the pressure of the system is critical and not to go by the guage on the store type cans. He said different cars had slightly different requirements.
Were I you, I would pay for someone to charge the system and check for leaks.

 

[bimmernut318]

Low refrigerant will cause the compressor to NOT clutch in! Be sure to add the refrigerant correctly, it goes in the low side (suction). If somehow you added it to the high side you could destroy the compressor and even worse, the can could explode as the high side runs at around 300 psi.

 

[joefrontier2]

I'm going to bet you need a new thermal resistor. It's behind the glove box, but inside the ac coil. This is a 30-40 dollar part and every 1st gen will need one as they have a tendency to fail.

I had this issue as it was not low refrigerant and it was blowing cold but cycling the ac pump.

 

[bimmernut318]

could also be the pressure switch

 

[southpole1989]

my bad i meant to change the topic to warm and i think i am going to take it to mechanic would there be a difference if i took it to an place that only does a/c services verses normal mechanic?

 

[bimmernut318]

my bad i meant to change the topic to warm and i think i am going to take it to mechanic would there be a difference if i took it to an place that only does a/c services verses normal mechanic?

Sometimes AC can be a biotch, someone that knows it can usually pinpoint a problem pretty quick rather than fumble around with trial and error. If you know a good mechanic that you trust let him take a peek. Hopefully it is something simple.

 

[joefrontier2]

Make sure you check the thermo resister!

 

[Rod and Recurve]

I have been dealing with the same problem for a while now. So far, my mech has replaced the compressor, drier and low side line. They still haven't found the leak. This is the mech that I have been going to for several years never an issue and always fair. But I've payed for diag test 4 times now. Going in for inspection this month and demanding a fix and not paying for diag. I only hope its not at the evap. $$$$. My suggestion is to find an a/c specialist or go to the dealer and get it fixed the first time.