Automotive Air Conditioning Information Forum

The specifications that I have for your 1999 Chevrolet Tahoe with rear A/C are as follows: 64.0 ounces net weight of R-134a, and 11.0 fluid ounces of oil—PAG-150 for an OEM Harrison compressor, or PAG-46 for an OEM Denso compressor. If the under-hood decal differs, the decal always takes precedence.

In addition to what Cusser said, bear in mind that a properly charged system with front and rear A/C will show pressures that are somewhat higher than vehicles with front-only A/C.

What color was the OT that you installed? It should be yellow (or beige) and white—0.062" orifice—with a single black ...

I agree with you. According to the sticker, this system was originally designed to use 900 grams (31.7 ounces net weight) of refrigerant, so that's how much the shop should have installed. The refrigerant amount must be correct for the system to cool properly and for the oil to circulate to ...

I have a 99 GM/Vauxhall Vectra... .
Yours is not a USA-spec vehicle, so I don't have any information on it.


I have never worked with AC before and didn't know they had different oil viscosities too... thought it was one fits all or period specific, asked a shop and the guy said "we mostly use ...

At first you mentioned that the compressor *is* engaging, then later you mentioned that the compressor actually *isn't* engaging. I'm confused.

If you're going to convert the car from R-12 to R-134a, you'll be better served, in my humble opinion, by replacing the serpentine-style OE condenser with the largest parallel-flow condenser that will fit. If you go with a modern PF condenser, you should be able to make up the hoses or lines (or ...

If I understand correctly, you replaced the battery, now the A/C compressor won't engage. Before doing anything further, scan the vehicle for Diagnostic Trouble Codes (DTC's), or have it done. Clear the codes, and you'll probably find that the A/C system works again.

If it doesn't, the system might ...

Thanks, Tim. The same to you and yours and to everyone on the Forum.

Okay, good.

I recommend leaving the '00 Silverado Dually alone until you get the '99 Yukon A/C system running well.

Does the A/C work in the Dually?

Thanks for the additional specs. After 26 years and a misplaced orifice tube, who knows if that accumulator is original. I'm guessing it is because the decal is a GM decal. I'll charge to that spec and report back on temps and pressures. I wonder if there was a TSB or other guidance from GM to ...