Air conditioning system help.

[Chris B.]

I bought a 1997 GMC sierra with only 75,000 miles on it and it is in great shape! The AC does not blow cold air at all. I'm going to try a recharge but if that does not fix it what should I do next? Do those "AC leak stop" products work? Worst case senario how much am I looking at to redo the whole system so it works again? Many thanks!

 

[Merkava_4]

First you need to find out WHY it's not blowing cold air. You may assume it's because all
the freon has leaked out, but it could very well be because the compressor is not working.

To save yourself some money, hire someone to find out the WHY and then take the truck
home and change out the parts yourself. After you get the necessary parts changed out,
then you can take it back to the guy and have him charge up your system.

 

[Chris142]

Quote:
The first step is to put a pressure gauge on the system and see what static pressure you're getting.

Stay away from stop leak products.
X2. Just because it's not working does not mean that it's out of refrigerant. But since it's got a compressor on it that tends to leak it very well may be low.

Stay away from the stop leak stuff. It wont work and will plug up the entire system which will cost a lot more than fixing the original leak would have.

 

[Texan4Life]

Quote:
Stay away from stop leak products.

+1 ...good news being a 1997 it is r134a.

It you plan on working on it yourself at all you will need a set of gauges. I think most parts chains rent them.

another test is turn it on max (engine running) and check if the center of the a/c compressor pulley is turning. If not it is either so low on refrigerant that it does not engage the compressor (keeps from trashing itself) or the clutch/wiring to the clutch is kaput.

Do you know if you A/C system uses a orifice tube or expansion valve?

 

[SrDriver]

Find someone that works on automotive air conditioning. They will have the tools so they can check for leaks, etc.

Many people that add refrigerant don't purge the hoses when adding it and end up getting air in the system. This can cause all kinds of problems.

 

[Texan4Life]

Originally Posted By: SrDriver
Many people that add refrigerant don't purge the hoses when adding it and end up getting air in the system. This can cause all kinds of problems.


+1 I have also seen people charging liquid into a running system. The only thing that saved them was they had an accumulator down stream from the low side port.

With summer on the way I thought about maybe doing a basic charging how-to.

 

[Chris B.]

Thanks guys!

 

[Chris142]

Originally Posted By: Texan4Life

Do you know if you A/C system uses a orifice tube or expansion valve?

His truck has an orifice behind the passenger front marker light.