Dye on 17 year old Delphi 6628

[Craigs]

New here to autoacforum and new to working on AC systems.

I'm the original owner. 17 year old GM truck. 200k miles, 4.3L v6. The bluebook on my truck is down to about $1000. I plan to keep the truck for another year or two and absolutely need the AC during the summers up here. Original Delphi 6628 compressor etc. System holds 1.8lbs 134a.

I think the compressor seals are blown (dye on housing), but wondering if maybe it is only a failed high pressure relief valve and hoping I could get by with replacing only the valve. Where does the relief valve discharge? At this point there are only a few PSI in the system. Compressor is fairly quiet when I jump the connector at the pressure switch on the accumulator. Certainly no squealing.

AC worked fine since new, until early last summer when it wasn't cooling very well. The clutch was cycling every 10 seconds. Bought a $60 set of manifold gauges and 134a to bring it into operating range. I didn't add dye or oil. I can't remember too clearly, but pretty sure I didn't top it off, but added only enough to stop the cycling and get some cold air. Blew cold all summer. Have not use it much since last October other than it automatically running when using defrost.

When I started using it again last month, there was no cold air. The static pressure was about 20 PSI. Added a 12 oz can (though it needed more). It lasted only a couple days. Bought a can that included dye. Leak at the switch mounted on the accumulator. It seemed loose when I put a wrench on it, so I just tightened it and added more 134a, aiming fill it and top it off. That leak seems to have stopped. But a week later, it's lost nearly the entire charge.

Now I'm noticing dye around the middle of the compressor, none on the "ends" None of the clutch or hoses or condenser. The middle of the compressor is dark with oil/grim, so much that I couldn't see there was a label. Since the compressor is mounted on top of the engine, i presume the grime is from compressor oil. I suppose the layer of dark grime indicates it's been leaking for a while. The is some pressure in the system when I burp the schrader valve, but it is very low, and it's too low to move the needle on the manifold gauge.

What should I replace? I have a vacuum pump, compressor, LP switch, accumulator and orifice tube on order.

[Dougflas]

Compressor is known to have leaks at the belly. It involves disassembly, cleaning the mating surfaces, and a new set of gasket seals.

[GM Tech]

Notorious "Belly Leaker" ditto the above comments- corrosion has grown under the seals of the belly o-rings- and caused your leak- I've resealed 100's of these- but you need the proper tools and know-how to do it- otherwise a new compressor is at hand....

[Craigs2]

Login problems with my initial account. Gave up and created a new one.

17 years and 200k miles, not bad, but given the current low value of the truck, I'd like to give it a try. Where can I find details of the repair procedure?

[Craigs2]

Photo of the compressor:

img_2570.jpg.1.jpg (79.26 KiB) Viewed 15327 times

[bohica2xo]

Here is the process from the archives:

http://www.autoacforum.com/messageview. ... adid=21972

It is a V5 compressor, but the process is similar.

[Craigs2]

Thanks for all the good info.

One commenter in that thread says 45-90 minutes by an expert. So maybe 4-5 hrs for me, plus parts and a couple tools, and the likelihood I wouldn't succeed.

I think I'll put in the new compressor when it arrives.

The 17 year old system has never been serviced other than a recharge last summer.

There is not enough pressure in the system to move the needles on my manifold gauges, but there is some because there is a soft hissing when a vent a schrader valve.

1) remove components:
a) compressor
b) accumulator
c) orifice tube
d) low pressure switch on accumulator
2) install new components
3) vacuum test for leaks
4) pull vacuum for 60 minutes
5) add refrigerant by weight

Ought I replace the condenser too? or do a flush (not certain how to do that or which is the correct point in the repair plan)?

[Tim]

Depends on how much debris you find. Condenser is not that costly and you're changing almost everything else.

[Craigs2]

Thanks. The compressor runs off the serpentine belt, so I am unable to use the truck with the compressor removed. Is it ok to drive the truck with the system open, for example with old compressor installed but disconnected, perhaps the accumulator removed, with various ports protected with plastic baggies or tinfoil? I read somewhere that air and 134 are combustible.

[Tim]

Yes, seal up all components not being changed.