'99 Tahoe air conditioner

[satisfactionII]

I'm trying to add refrigerant to my taho 's A/C. Its a ho all right.
Does anyone know the location of the service port?

There are two ports on the compressor and when I attached the gauge and can of sealant to the low pressure side(the only one the hose would fit) the damned gauge went to 90 psi. I popped the gauge off real quick. Help a brother out.

[Michael Garibay]

Since your a Scarab guy I'll help. First off -----DON"T EVER ADD SEALANT TO AN A/C SYSTEM----- You will F#%K up the recovery machine of the next shop who works on it. Next if it has 90 PSI your problem may not be refrigeration. Does the compressor come on?If so does it cycle on and off rapidly?If it does come on(the compressor) without cycling let it run for a minute or so and grab one of the pipes coming out of the accumulator(round silver canister by passenger side firewall) with your hand, are the lines cold (i.e.40-45 deg F)? If so you may have a blend door problem under the dash. Otherwise the fittings on the compressor are as follows- Large diameter=High side, Small diameter=low side(charge side). With the A/C (compressor) off the low and high side fittings will be about 90 PSI stagnant. Once the comressor is running (assuming it functions) the low side will drag down to about 28-35 psi and the high side will rise to 200-275 psi depending on ambient temp,charge amount etc.BTW most leaks are at the compressor or charge fittings so look for oil accumulation and dirt at these points. Good Luck- Michael Garibay (owner -Quality Auto Service Pomona Ca.)

[satisfactionII]

I don't think I got much sealant in there, most of it went onto the lawn just spewing out of the can. I wen tback out and statred the truck and the compressor does engage but cycled on and off every few seconds. I added a can of refrigerant and it seemed to take that but did no good because the A/C still blew warm air. Just before I shut of the engine the compressor stopped cycling on. Any ideas?

[320es]

It has been a while, but I thought you needed to jump across a couple of terminals on plug on the accumulator so the compressor runs continuous while your charging. I know that is what you have to do on the chrysler products.

[Michael Garibay]

First off 320es, a Tahoe isn't a Chrysler product, probably just misread. It is hard to just add a pound of refrigerant. R134a systems are actually VERY sensitive to charge. Too little and there isn't enough refrigerant to circulate the oil and it will collect in the evaporator core and eventually smoke the compressor. Too much and the high side pressure will hit the critical 400PSI and again- smoke the compressor (if there is no high pressure cut off).Also when the system is ran low, air generally works its way into the system and hampers the refrigerants ability to cool - i.e. 68 deg vent instead of 42 deg. That is why the best way to charge A/C is to evacuate the system . This vacuums out ALL air and boils all moisture ( water boils at 70 deg F in 30 inches of vacuum). Then recharge the system BY WEIGHT on an A/C scale insuring the exact amount is reinstalled. Note: try not to add oil if possible-its a common mistake that is done that fills a/c systems with way too much oil over the years eventually bogging down the systems ability to cool.

[320es]

I know a tahoe isn't a chrysler product. Just saying that is what has to be done on chryslers and that it may be the same on the chevys.

[Michael Garibay]

Yes,like a Chrysler , a Tahoe has a clutch cycling switch and you can jumper across to fire the compressor.Mike

[Wally]

If you bought one of those quick fix cans then it will only fit on the proper fitting......ive done this before on my wifes jeep and you need to verify you have the connection all the on...if not you will get some crazy readings.....i usually start the truck..turn on the ac system and connect the can to the port....with one had on the connection pushing down to make sure its connected properly.

On the Tahoes i know there is also a low psi sensor that wont let the compressor turn on if theres not enough psi in the system....found that out when my condenser had a slow leak in it!