AC flush question

[68Timber]

The compressor on wife's 03 Yukon locked up so I ordered a new compressor kit from Rockauto. I haven't had to flush one before and don't have a clue what works best. Any recommendations?

[clinebarger]

Rear air?
Compressor locked up or Clutch bearing locked up?

[68Timber]

It does have rear air. I don't know if it was the clutch or compressor though. How do you tell? When it locked up it melted the belt.

[clinebarger]

There is a bolt in the middle of the clutch (10mm or 13mm forget which). See if it turns freely, If it does....The compressor itself is fine, The idler bearing is locked down. Replace the idler bearing or the entire compressor, But no flush needed.

If it does not turn...The compressor is internally locked. The entire system will need to be flushed, New Compressor, Accumulator, Orifice tube & the rear unit will need to come out to replace the Expansion valve.

Let me know & I will help with oil volumes & procedures.

[68Timber]

Originally Posted by clinebarger

There is a bolt in the middle of the clutch (10mm or 13mm forget which). See if it turns freely, If it does....The compressor itself is fine, The idler bearing is locked down. Replace the idler bearing or the entire compressor, But no flush needed.

If it does not turn...The compressor is internally locked. The entire system will need to be flushed, New Compressor, Accumulator, Orifice tube & the rear unit will need to come out to replace the Expansion valve.

Let me know & I will help with oil volumes & procedures.

It is fully locked up, nothing is turning. I ordered the kit and have all the above, arrived yesterday. I hope to tackle this Saturday and get it done.

[Boog]

:Yow. I had a compressor lockup on my old 97 GMC some years back. The daughter was out of town late evening. When I got there the parts stores were already closed so no chance of replacing the compressor only so she could drive it back home. Had to call a tow truck.
That's the main drawback to a single drive belt setup as I see it.
Be careful removing the ac lines on the rear evaporator. After some years they tend to weld themselves to the evap. Aluminum so. I had to replace the rear evap on my old Burb because of those lines. It wasn't particularly expensive though.

[68Timber]

Originally Posted by Boog

:Yow. I had a compressor lockup on my old 97 GMC some years back. The daughter was out of town late evening. When I got there the parts stores were already closed so no chance of replacing the compressor only so she could drive it back home. Had to call a tow truck.
That's the main drawback to a single drive belt setup as I see it.
Be careful removing the ac lines on the rear evaporator. After some years they tend to weld themselves to the evap. Aluminum so. I had to replace the rear evap on my old Burb because of those lines. It wasn't particularly expensive though.

This is on that 4.8 motor, so the compressor is down low near the frame instead of perched up top like on the 5.7 Vortec's. I haven't messed with AC too much but most of this job is documented OK on youtube. The only thing I haven't found yet is replacement of the rear expansion valve. I need a vid or exploded view or something to start with there. So yeah, won't be much motorcycle play this weekend.

[68Timber]

I also need to flush the rear. Can I do this where the expansion valve attaches?

[clinebarger]

Originally Posted by BRUISER

I also need to flush the rear. Can I do this where the expansion valve attaches?

Remove the rear HVAC module, Split the case, Remove Evaporator core, Remove expansion valve, Flush Evap. core, Flush both lines that run front to rear, Reinstall Evap. core with new THX valve.

[68Timber]

Well, that was fun. All done and charged, front blows cold and the rear does not, but the rear line is cold where it bolts to the manifold at the rear floor pan, so I'm guessing the new expansion valve is clogged. I guess the flushing I did didn't get it all. So, question - would you install an new expansion valve only or should I flush more? I did flush the rear evaporator core while it was apart, so it's not clogged.