97USSBurb

Thanks to anyone who can shed light on the A/C sytem questions below and provide info on anything else we should look for.

FACTS.

A/C Compressor not working. However when jumper is used on relay near the dyer it works. But the air is not cold even with the compresor working.

We added R134 until it would not take anymore. About 2 or 3 small cans.

We found a suggestion on-line that a dirty orifice tube was normally a culprit when the A/C system failed.

So we bought the orifice tube and the switch on the dryer that activates the compressor.

My questions are:

1. Should we allow an A/C mechanic to take care of this whole thing or could we utilize the mechanic for the evacuation, vacuum test, and refill of the system only? My son and I are compotent with wrenches and do a lot of normal component replacement to save money.

2. Is the orifice tube the most likely cause for this problem?

3. Does the relay / compressor switch located on the dryer shut down to prevent the compressor from running when oil is not reaching the compressor? (or has it simply failed with age?)

4. Should the condenser automatically be replaced on this 13 year old vehicle? We heard it was a common location for debris to build up. Sounds logical to me given the size of the fins for cooling.

5. Should all major components (all under the hood) be removed and cleaned with high pressure air to remove debris or should they be cleaned with something else?

Thank you for your input. We want to fix this for the least amount possible. Even if it's believed we should have someone else perform this maintenance I'd like to understand the cause(s) first. I've always thought the more you know about something the less likely for being taken by a less than honest mechanic.

Thank you again.
Monty

grendl

Had recent problem on 97 w/dual a/c. Front blew hot, rear blew cold. Turned out the orifice tube had gone (again, 3 time in 8 yrs). Replaced, recharged & took care of problem. They use an orifice for the front part of the dual system & an expansion valve in the cargo compartment for the rear. Don't run with the pressure switch on the dryer bypassed- can burn up compressor if go low on freon. Pressure switch reacts to psi, not oil. Only parts changed in my burban's a/c are pressure switch, dryer (2x), compressor (1x) and the hoses to/from compressor. Has 135k mi & a/c is on everyday in S. Florida. Hope this helps.