Guilty

Hi guys

So I just had my A/C compressor replaced for the 2nd time and I was wondering what made it break down the way it did. The tech told me that the compressor literally fall apart...

There is a year warranty with the new compressor but still...

He told me it's a common problem with the 63 engines (M156)... Is there something that I'm doing wrong? Maybe it's because I downshift a lot at high rpms?

Any help would be appreciated... Thanks!

Sincity

Common problem with the M156??? Never heard that one and not sure how a compressor issue could be related to the block it's mounted onto. Perhaps the heat emitted by the M156???

Guilty

I was surprised he said that too.. I've never seen anyone here complaining about the A/C besides me lol

b16

what were your symptoms?

Guilty

None. It just breaks down and stop blowing cold air.

Mikegpr03

If the AC system is not properly flushed out when the 1st one broke then there will be tiny metal particles in the lines ( basically sanding the inside of the new compressor ). Those metal particals will ruin the compressor. One theory, I say say for certain because the thech might have flushed your system out properly. Ragging on the car left and right will ruin the AC too. When you road race the AC is off not on so thats another way to ruin it too.

Guilty

Thanks for the explanation!

m a x i m u s

interesting. can you explain some more? thanks.

AMGTTV8

+1

Doesn't make any sense at all

Mikegpr03

When you "step on it" the AC system shuts off ( compressor ) as soon as the rpm's drop down the AC compressor clutch kicks back on. When you road race the AC is typically off. When your constantly stomping the gas what I just explianed happens over and over again on/off on/off and so on. The compressor is controlled by many paramiters ( rpm, temp, line pressure high/low line pressure ) so the best thing to do is just turn it off if your going to be "stomping the gas over and over" that way you don't tax the daylighting on the AC compressor. I hope this helps. Maybe someone with more knowledge on this can chime in.

Guilty

That explains many things. I always downshift at high RPMs... I thought I was helping the brakes (and my wallet) but it looks like I'm gonna need to stop doing that unless I want my car to back to the shop again.

IStern

I've read conflicting articles about the effects of engine braking, but personally I think brakes are a lot cheaper to replace than your motor/transmission.

Guilty

My rotors are $900 EACH + Pads.

RSF C63

That might be but your motor alone is $40k to replace plus labor and I don't know what a transmission is worth. I however think that engine braking is worth it just for the sound it makes while doing so.

Guilty

Yeah, you're right. Now I only downshift at low RPMs. I don't wanna break my A/C again in Miami weather... thanks for the tips guys

Quadcammer

Modern mercedes a/c compressors have no AC clutch.

Shifter

This is correct, they are always spinning. There is a wobble plate that is controlled by duty cycle depending on request and load etc.

Mikegpr03

Yes you guys are right. However that load on/off will ruin the AC compressor