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My AC compressor clutch froze up. For now, I installed a belt that bypasses the AC. I ordered a new compressor, condenser, dryer, expansion valve, and o-rings.

I asked a local mechanic if we would flush the system before I installed these parts (I don't have a compressor). He said as long as I was replacing the condensor and other components there was no need to flush the lines. He said to go ahead and install the parts and then he would evacuate the system, check for leaks, and install new refrigerant for $260.

Is this good advice? Obviously I'm concerned about metal shavings in the lines.

Thanks

1996 Camry LE 2.2l
 

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If it was the clutch that failed, there won't be any metal shavings to worry about, in the lines, because it is located outside of the system. For a compressor failure to put junk into the lines it'd have to be in the pistons, or the valve assembly, inside.

Note that although flushing the lines sounds straightforward once the condenser, compressor and receiver/dryer are taken off, there is still the evaporator matrix, buried deep within the HVAC assembly, behind the instrument panel (it is the very first part put onto the car, and the hardest to get to). If you did put some kind of flushing agent into it (note there are very small orifices in a matrix), it'll be quite a challenge to get it all back out before re-assembling the rest of it.

The Condenser is considered the "basement" of the system (lowest pressure), so replacing it is typically considered the thing to do when something goes wrong in a big way (and the dryer, as it often gets used up when the system is opened to atmosphere).

Once everything is fully re-assembled, your mech will evacuate it and check for evidence of any leaks, and doing that will tend to draw out any remaining oil, so he can install the proper volume of oil for the system without over-filling it, and doing that step (oil removal) will tend to draw out any microscopic things in there (suspended in the small amount of oil being drawn out).

After you have assembled everything, be sure to NOT power up your AC until after the system has been evacuated, filled with the proper volume of oil and pressurized by someone with the proper tools/equipment.

I'm not an AC tech, but these are the things I've learned from recently doing a lot of research trying to learn about auto AC for my own project. Hopefully it is helpful.


Oh, by the way, you'd mentioned replacing the expansion valve. I am not sure how that can be replaced without pulling the dashboard, and the HVAC unit, and removing the evaporator, as it is mounted right to the side of the evaporator on most cars, inside the cabin and not accessible from the engine bay. I wondered if when you said "expansion valve" if you really meant "receiver/dryer" which is located right next to the condenser and easily accessible as they are often replaced together.


Another thought: while changing the O-rings, you will have all of the pipes out of the car, from the firewall to the front of the engine room. At that moment, since it is risky that some dust/dirt could have gotten into them, you'll want to blow them out really well with compressed air (and maybe some brake cleaner, something that is known to leave NO residue), let them dry, and then tape their ends to keep them sealed during re-assembly, until ready to make the final connection to their mating part. Surgically clean is the order of the day during AC assembly, to prevent leaks (even a human hair / eyelash can damage an O-ring enough to cause a leak later). Also, make sure any gloves you may use are fiber-free, and completely dust free (no talc). If in doubt about how you've handled an O-ring, replace it with another new one, to be on the safe side.

Use new AC lube (the same as will be used in your compressor) on each O-ring to aid assembly and further prevent damaging it.

Do not allow either of your flex hoses to become kinked, as that damages its vapor barrier layer and can lead to super slow leaks.
 

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When you say that the clutch froze, do you mean that the compressor was on all the time? Or do you mean that the compressor would not turn, with resulting belt squeal/smoke?
 

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When you say that the clutch froze, do you mean that the compressor was on all the time? Or do you mean that the compressor would not turn, with resulting belt squeal/smoke?
The compressor would turn, but the pulley was starting to wobble and I could hear the clutch scraping several days before it failed. It failed while I was driving. I smelled plastic burning and pulled over. There was plastic dripping from between the clutch and compressor. If I recall correctly, I had the AC off because I knew it was on its way out, but not sure.
 

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As long as the compressor didn't come apart internally, you should be fine without a system flush. If you're confident of your shop, go with their recommendations.

THAT SAID, I just had a compressor & condenser replaced and my shop introduced dirt into the line. My expansion valve is partially clogged with something and my a/c is far from fully operational.... all for $950.

This is the first time my shop messed up this big. I've had great service from them for more than 9 years. Unfortunately, it's the last time I'm taking major repairs to them. There's a comparable shop here in town that I've used in the past, and I'll be going to the second shop.

I've taken it back and they did what they could, of course for free. It's much better than it was immediately after the, er, "fix." But still not anywhere near where it should be... cycles too often and for too short a time.

Just take a gander at your shop's bays. If the place is not totally ship-shape and gleaming, maybe find a more clean-oriented group.
 
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