A/c Needs Help On 2000 Gtp!!!!

Driving home the other day from a trip and the air condition just started not blowing ice cold air.... It still blows mildly cold air but its not even cold enough to cool the car down. I have one of the self pressure testers and I checked the pressure and it said it was at around 70psi ... I know that they should only be around 30 to 45 psi.. The ac Has never been touched since the factory.! Can someone please help.... Thanks for your time

Also, I'm just using the little do it yourself psi checker that comes in the kits that you can buy at the store to recharge your machine. I checked using the port in back by the firewall. With the a/c on it give a reading of just over 70psi and with it off it gives me a reading of 100 psi? Any ideal what up with this? Its to hot to be riding around town with no air!! :-) Thanks for all your comments so far...

A lot of times checking low pressure with one of those kit gauges really doesn't help to properly troubleshoot the system. If the gauge you are using has any accuracy then the reading at the low pressure port is abnormal. You'll need to check the high pressure port which will require another special gauge and fitting.

Then you compare the high and low pressure readings to determine the cause. When the low pressure reads high it could indicate blockage like at the expansion valve, accumulator or even a bad compressor.

Welcome to AF.

how would I go about changing the expansion valve ?

Any ideals for my problem? THanks

Any ideals for my problem? THanks

how would I go about changing the expansion valve ?

I'd be reluctant to replace any A/C part without full diagnostics. Checking high pressure is critical to determine what the possibilities are.

Unless you plan on dumping all of your R134a refrigerant in the air then normally the old refrigerant is recovered and stored. Then you can replace the bad part. After that a vacuum check is run and system checked for leaks. Then the refrigerant can be added back. Also, you may have to add some GM approved PAG oil for the compressor.

The compressor needs to be running while your pressure testing otherwise you will get a high pressure reading like 70 psi. With R134A you should be geting pressures around 25-32 psi while compressor running.

The compressor needs to be running while your pressure testing otherwise you will get a high pressure reading like 70 psi. With R134A you should be geting pressures around 25-32 psi while compressor running.

You'll get higher than that with the compressor off but it is irrelevant to check low pressure off. The pressure you will read at low port is based on the ambient temperature and can be much higher than 32 psi.

BTW - Carefully read and check out his post #2 quoted below:


Also, I'm just using the little do it yourself psi checker that comes in the kits that you can buy at the store to recharge your machine. I checked using the port in back by the firewall. With the a/c on it give a reading of just over 70psi and with it off it gives me a reading of 100 psi? Any ideal what up with this? Its to hot to be riding around town with no air!! :-) Thanks for all your comments so far...

With the compressor on i get a reading of alittle over 70 with it off I get around 100. Thanks so far!!!

Ok found out that the A/c compressor and and Accumulator is bad.. Can someone post some instructions on how to replace them and if there are any special tools needed? Thanks

Do you plan on doing the complete job DIY without any assistance from an A/C shop?

Also, I'm just using the little do it yourself psi checker that comes in the kits that you can buy at the store to recharge your machine. I checked using the port in back by the firewall. With the a/c on it give a reading of just over 70psi and with it off it gives me a reading of 100 psi? Any ideal what up with this? Its to hot to be riding around town with no air!! :-) Thanks for all your comments so far...

As said the one hose stop and go gauge is not very good.
Here is what you need for proper testing.
http://www.ackits.com/merchant2/merchant.mvc?Screen=PROD&Store_Code=AMA&Product_Code=66773
Also do not use the recharge kits that have the stop leak crap and seal conditioner and oil in them.
MT

My friend is a GM tech. So he is going to help me!! Thanks