Car A/C went out last night. Associated with the failure was smell reminiscent of burning brake pads.
The compressor clutch does engage and the pulley/clutch assembly is turning. I haven’t checked refrigerant but this was a very sudden failure - A/C was perfect minutes before.
My inclination (after checking pressures) is to replace the compressor and the drier element. I’d also flush the system, which leads to my question: What are the chances the compressor failed in a way that would inject debris into the system? Do I need to be worried about my expansion valve(s) or debris in the condenser or evaporator?
Yes You should flush your system & replace the components. If you could back flush the condenser, that may help in keeping the system cleaner. I had mine crater a few months ago. I was surprised that debris made it through the condenser, since it’s Micro-channel, & into the orifice/strainer.
Here is a picture of my strainer/orifice
Do I need to replace the evaporator and its expansion valve(s)? God I hope not. Talk about work. Can I just flush those? I don’t mind replacing the condenser.
Tim, your clutch bearing looks like an experience I had years ago on my old truck. Unfortunately I was driving near Marble Falls when that happened, keeping me sidelined for a day.
Your orifice tube is nicely discoloured with debris!
Same thing happened to me on my 2011 VW Jetta a few years ago. Took 2 months to get an appointment with the dealership and it cost $2500 to repair. Didn’t want to chance having debris still in the lines destroying the new components so they replaced nearly everything in the system. AC blows ice cold now! Not a job I wanted to tackle myslf.
Ordered new Denso compressor, condenser and expansion valve. Do you figure I can get away with just flushing (not replacing) evaporator? Removing the evaporator looks to be a huge PITA. Even flushing it appears to be difficult without getting flushing solvent all over the inside of the car (unless I backflush with the expansion valve still in place).
Also: after flushing, can I just blow out with air for a bit and then rely on the vacuum pump to boil off any remaining solvent - or do I need to flush with air for a really long time?
Have you actually IDd the problem? This description makes me think burst rubber hose or belt. Kind of weird in a modern car, since most of them are factory-design & built (as opposed to 1970s & 80s where most/many were dealer or after market add-ons), but still, most failures that cause flushing/replacing heat exchangers & compressors don’t make smells, especially inside the car.
There is no such car made in recent history with an easy to remove evaporator. I wouldn’t worry about flushing much depending on what you find in the orifice tube.
My personal view is - if the clutch or clutch bearing goes - I would replace the compressor instead of the time and parts to only service the clutch.
Usually there’s other signs/noises before/as a compressor causes clutch failure, so if there were no other indications on a new clutch install, I’d have to ask if the clutch was clearanced properly. But then, I know you’re going to do that, so…
Well, then. Good luck, Matt! Hope it’s easier than it appears!
I did have the clutch coil go out once and that was a relatively easy and inexpensive replacement. But for this one, yeah, something mechanical definitely happened. I suspect the internals of the compressor seized up and as above ^ I was smelling the clutch burn up.
I agree with you that a compressor replacement is probably the best way to go. The compressor is easy to replace but that expansion valve is a bitch to get to and the evaporator is well nigh impossible without taking the dash apart.
(almost) doing the same job twice in a few months after in the event of replacing the clutch and or bearing task to me is not worth the hassle of doing ‘everything’ and restarting the ‘clock to zero time’.
Mark - Denso is the way to go! Buy it one time and done.
20.0 hours on some S class models for an evaporator - but Mercedes A.G. was kind(sort of) if the customer paid for a genuine Mercedes Evap - then if it failed again, Mercedes would cover the labour as well as the part.
You probably have access to different equipment than me, but also, I grew to hate opening Schrader valves on R12 systems very early in my mechanic life, and it’s hard to put away those those lessons. I had more of those leak than any other problem with R12.
