I have a high-mileage 99 chevy Tahoe and I've determined (mostly due to
loud clanking noises) that the A/C compressor has failed and needs to
be replaced.

Ok, so I've removed the compressor as well as the accumulator, the
front orifice tube, and the rear A/C unit expansion valve. I didn't
see any debris in any of these places so I'm going to keep the existing
condenser, evaporator, and tubing. This is an R134a system and the
warning label on the accumulator says to be sure to add proper
lubricant (i.e. PAG).

My service manual says:

"Determine the amount of oil remaining in the accumulator and add that
amount."

In another place it says:

"Determine the amount of oil remaining in the compressor and add that
amount."

Hmmm, confusing...

The problem is that there is no oil, at least none that I can find, in
the accumulator or in the compressor. I do find "trace" amounts in
that if I stick my finger in the accumulator there is a film of oil
there as is to be expected.

So my question is HOW MUCH oil is to be added to this system prior to
recharging with R134a? And where should it be added? One place in the
service manual says add it to the compressor, another place says add it
to the accumulator. Also, WHEN should it be added? Prior to
evacuating the system or after evacuating but prior to adding the
R134a?

I don't want to trash my new compressor before it even gets going...

Thanks, and any other tips on this particular system would be
appreciated. BTW, this is the 4x4 4-door Tahoe w/ 5.7L V8. Has the
rear A/C option as well.