AC repair

[Blue Bowtie]

Those compressors are notorious for leaks at the two case end "O" rings. If you get seven-ten years out of one of the earlier units, consider yourself very fortunate. Reportedly, the newer units (2003-up) have been redesigned to address that leak problem, and the new (not rebuilt) aftermarket units I've installed in the past few years have not come back for leakage. I think they might have wised up and installed quad rings instead of "O" rings in those locations, but I'm not sure.

It won't hurt to replace the components, drive it for a while with the AC clutch wire disconnected (it shouldn't run with no refrigerant charge anyway, but it's a sure thing if the clutch is disconnected), then evacuate and charge it later. Oil is critical, and you need to add the correct volume of PAG when installing the compressor, then manually turn the compressor to distribute the oil and clear the cylinders.

Definitely replace the orifice tube/screen unit and at the very least, remove and clean the accumulator, or just replace it.

[MT-2500]

Originally Posted by gold10go4

Manic
Thanks for the response. The issue of flushing is a little perplexing. I know GM doesn't recommend, but every aftermarket supplier seems to. In fact warranties are voided when flushing isn't done in most cases. I'm inclined to do without the flushing since the flushing seems to be the most tedious part of the job and I don't have the best equipment to do it. Since my compressor was only leaking, and not disintegrating, I'm inclined to just replace the comp, accumulator, and orifice. If there's any buildup on the orifice, then I'd probably do a flush to be safe.

I believe the schrader valve that's leaking has the removable core, in which case I'd just replace that. I have to look at it a little closer. It does appear to have a male fitting screwed into the service line if I remember correctly, so I'm not sure where the entire fitting would be purchased if the core cannot be removed. I haven't seen anyone advertising the entire fitting - just the cores.

Question: if I were to disassemble the components and replace with the new comp, acc, and orifice but don't evacuate and recharge right then, will that cause problems? In other words, if I replace the components and drive the vehicle for a few days before recharging, will I create problems (moisture, etc.?) I'm thinking with my time schedule I may have to split the repair in two parts.

To keep system from drawing moisture.
Best to pump down and recharge as soon as you can after installing a new reciever/dryer.
After the sealing caps are removed from a dryer they tend to start drawing moisture.
That is one reason for a good vacuum pump down.

As Blue Bowtie says the correct amount and correct oil is very importain.
That is where a fush comes into play.
After a fush it is easy to get the correct amount of oil in it.
Good Luck

[manicmechanix]

Originally Posted by gold10go4

Manic
Thanks for the response. The issue of flushing is a little perplexing. I know GM doesn't recommend, but every aftermarket supplier seems to. In fact warranties are voided when flushing isn't done in most cases. I'm inclined to do without the flushing since the flushing seems to be the most tedious part of the job and I don't have the best equipment to do it. Since my compressor was only leaking, and not disintegrating, I'm inclined to just replace the comp, accumulator, and orifice. If there's any buildup on the orifice, then I'd probably do a flush to be safe.

Well you know how it is. The aftermarket suppliers probably reason that most people aren't going to flush the system or be able to prove they did, so it gets them out of honoring warranties even if it's their product that is to blame for a failure. The main thing is if you see no signs of debris, it's best to not flush it. And if you had debris you wouldn't be able to flush it out properly anyway yourself. You'd probaby need good flushing equipment and removing and cleaning/replacing condensor and other parts.

Question: if I were to disassemble the components and replace with the new comp, acc, and orifice but don't evacuate and recharge right then, will that cause problems? In other words, if I replace the components and drive the vehicle for a few days before recharging, will I create problems (moisture, etc.?) I'm thinking with my time schedule I may have to split the repair in two parts.

I agree with Blue Bowtie that it won't hurt to drive it for a few days. If you have it all sealed up good with a new accumulator, when you pull a good vacuum on and hold it for awhile it should get about as dry as it would've anyway.

[gold10go4]

I am preparing to replace the parts on my AC, but had a question specific to the S10. Does anyone know exactly where the orifice tube is located? There don't appear to be any obvious places.

Also what kind of CFM's are needed for good evacuation? I see lots of air operated pumps, but the CFM's are in the 4 range. Don't know if this is enough.

Thanks for your help once again.

[brcidd]

OT is in evaporator inlet-at bottom of Evap- have to remove accumulator to properly access-

[gold10go4]

Thanks, br

That's no problem. I'm replacing the accumulator as part of the package.

Do you know what "good" pressures should be on the low and high sides?

Also, my accumulator is on the low side. Isn't the accumulator usually on the high side?

[MT-2500]

Good low side is around 28-32 lbs.

Remember evaporater out let tempt is close to low side tempt.

30 lbs = 30 degrees = cooling.
High side depends a lot on engine cooling and outside tempt.

150-250 is good high side range.
Good Luck