99 GMC SLT Suburban front A/C problem

I have front and rear air.The rear air is coming out cold but front isn't.I have 78,000miles on it.I had seals replaced on compressor about 5000 miles ago.Any ideas?

This is going to the Suburban forum below for more attention.

Auto matatic or manual controls?
What is the vent tempt on rear unit?
A low charge will rob one end on cooling.
Is the compresser cycling on and off often?
Any fresh ac oil around compresser or lines?
What are the AC low and high side pressure reading at idle and at 2K RPM with compresser running?
Is vent controls on front working right?
Defrost /floor and vent OK?
Does front tempt control go from hot to luke warm or just stay hot?
Or can you hear the inside door change when going from hot to cold?
Any flashing lights on controls?
Has battery been dead or changed or jump started before it done it?

We need low and high side pressure readings to start with?

I had the same problem last year during the cooling season. I had good pressures, but after wading through numerous posts from people who were having the same problems I wound up adding two more pounds of freon. My pressures didn't change. Apparently, because the dual system takes up so much volume you may still readgood pressure but not have enough freon to satisfy the capacity of the system. Try adding one pound of freon and see if the front starts blowing cold. If it does you obviously have a leak. I believe I have a leak. I just haven't found it yet. Check through the threads from about nine months ago to get a better handle on this re-accuring problem.

1-19-05 - repairman found leaks at the compressor and they used a compressor seal kit. My car uses R-134.That was 5600 miles ago.I keep the car in the garage and dont drive it much. I bring it out every couple of months and run it including A/C.This car is really clean and never abused.

Auto matic or manual controls? <---manual

What is the vent tempt on rear unit?<----42-44 degrees

A low charge will rob one end on cooling.

Is the compresser cycling on and off often? <--- it is not cycling off and on when I look under the hood and listen. I thought maybe it was staying engaged because the front is not cooling and it continues to try and cool it.But I can hear it initially engage when I first turn it on.

Any fresh ac oil around compresser or lines?<--- no

What are the AC low and high side pressure reading at idle and at 2K RPM with compresser running?<--- don't have the equipt to check?

Is vent controls on front working right? yes

Defrost /floor and vent OK?<----yes

Does front tempt control go from hot to luke warm or just stay hot?<--- goes from hot to luke warm.When I first started the car in the garage the front temp was about 54 degrees with one of those A/C temp guages that fit in the vent.
Or can you hear the inside door change when going from hot to cold?
With the key turned on and the motor not running I can turn front temp guage on the dash from cold to hot and I can just hear something moving which is pobably that door.When I turn it back to cold from hot I hear the sound again for just a moment and then it stops.

Any flashing lights on controls?<---- no

Has battery been dead or changed or jump started before it done it?<---no

We need low and high side pressure readings to start with? <---don't have equipt

Question - How does the rear stay cold if the front is warm? Using one compressor wouldn't the system eventually leak out so neither was cold?

If R-134a is low one end will rob the cooling from the other one.
If out of r-134a it will not cool on either end.

First thing get the system checked for low R-134a charge.

And recheck the system for leaks.
Sometimes a front seal does not always fix the compresser leak.

It will need a set of low and hight side gauges put on it to test and recharge.
MT

MT-2500 -if the system is low do you think it is low because it is leaking.I have a repair shop that has always treated me well. i just dont want them filling the system if that is the problem and not finding the leak.

It is either low on charge or a bum pump---really need those pressure readings--

see if compressor spins very easily (with engine off) or if it has little rough "catches" as you turn it-- if catches are detected your pump is probably shedding its suction reeds-one piston at a time- some refer to this as an imploded compressor- then look for shrappnel in the OT if this follows suit....

Re: 99 GMC SLT Suburban front A/C problem
It is either low on charge or a bum pump---really need those pressure readings--

see if compressor spins very easily (with engine off) or if it has little rough "catches" as you turn it-- if catches are detected your pump is probably shedding its suction reeds-one piston at a time- some refer to this as an imploded compressor- then look for shrappnel in the OT if this follows suit....
Answer ---->>> compressor spins easily with belt off and it doesn't catch. Like I said I put on 5600 miles in 3 .5 years. If the A/C repair shop can't find a leak and the compressor seems fine I think he will suggest just adding some more R-134a and see how long it last to save me some money. Why pay $1200 to replace a compressor/fix everything and leave it sitting in the garage most of the time? But I would think it should not be a problem to find a leak. It is just how much do you want to pay?Any thoughts?
Question ---> some refer to this as an imploded compressor- then look for shrappnel in the OT. I am assuming shrappnel is bits of metal and OT means what?

yea right

OT=orifice tube - the hi to low expansion device- that has a filter and/or screen in the inlet....

May I add an extra question to this post? If the compressor cycles off and on about every 3-4 seconds, the rear is blowing cool, front hot, and the lower metal A/C line is so hot you can't hardly touch it, does that mean the oriface tube is clogged. I tried to add a little 134-a to the system with a DIY kit and it took some, about 6 onces, then showed high pressure on the built in guage. It still cycles like it did.

Best to start a neww Thread/post on yours.
And we will need the low and high side readings at idle and at 2K rpm with compresser running.
MT