jdsho

I don't know what's wrong.

I just got home about 6 hours ago from a 90 mile drive. I was in another area for work. Anyways...

just got done with the gym and on the way home, I turned on the heater. bc the windows fog up with the heater on, I always keep the heater on with the A/c. I turned on my car, and noticed there was a strange noise--almost like a vacuum belt that is off track or something. When i would rev the engine, even slightly, the noise would grow with it. I turned off the A/c (button) and the noise stopped.

I tried turning it back on and revved to about 3000rpm. When i did that, I heard a slight pop! like something snapped.

WHAT ON EARTH IS GOING ON?

I drove home with the heater on and the windows fogged up (even with the A/c button pressed)...I think something is wrong with the A/c?

I tried turning it to cold and it wouldn't get cold...I waited about 4 minutes..and it was lukewarm. ITS 55 degrees outside..

help?

PS I was in a car accident last october and they had to replace the entire air conditioning components (so they say). my car only has 50k miles on it.

acr2001

Sounds like your A/C compressor is toast. Sorry.

Unless your belt snapped... but you probably wouldn't have made it home! So I think we can rule that out.

LILBENZ230

You're not getting any low voltage warnings, are you? I've read about a bearing on the alternator that can give way and destroy the A/C compressor. I can't be sure, I'd have to read up on it.

samaritrey

have you opened you hood to check anything? i would get a buddy/wife/GF/BF or someone to start your car while you are looking under the hood to try and pinpoint the noise.

Glyn M Ruck

Sounds like the Compressor failed. Check the Poly V belt. Did you see a cloud of white smoke when you heard the pop? You might have blown an aircon hose.

The fact that the noise increased with revving the engine makes it most likely the compressor or compressor pulley.

jdsho

the noise went away after the pop! sound.

Now the air is not conditioned, whether the temperature is on cool or warm.

I had a car accident back in October.. it was a front-end wreck, there wasn't a whole lot of damage to the body, however mechanically, it was kinda bad. They had to replace most of the air conditioning parts with new ones. SO, that being said, I took the car back there thinking it was probably a part that they screwed up on that finally gave way.

They took it to some random european repair place that works on bmw and mercedes benz so they could plug it in to the star diagnostic thing. AFter that, they said it was the switch in the interior of the car.

My thought was...how can a faulty switch make my car create noises like that?? It was so far fetched...imo. I called the European auto place and asked the guy if the repair shop worker told him about any of the noises that I experienced--he said no. He did check the clutch and said it was working and said that I needed to purchase a new $460 switch (they are like $150 on ebay) and that would not include the $80 i had to pay for the diagnostic work.

WHAT THE HELL

LILBENZ230

The clutch on the A/C compressor?

According to this thread: https://mbworld.org/forums/c-class-w...dle-speed.html

There is NO clutch on the A/C compressors for any W203 of any year. Glyn is a very reliable source of information. So I would immediately call BS on anyone who checks something on my car that doesn't exist.

acr2001

You've experienced one of the many useless rip-off repair shops! It seems that there are more and more of them these days. You need to take your car elsewhere before those idiots cause further damage.

jokerswld34

That's funny because when my A/C compressor went, the dealer explained that the compressor clutch had failed. They said that the clutch has a fail-safe mechanism so that when it fails, it fails disengaged so the car is still driveable. I also heard a "pop" sound when the A/C started blowing out warm which was the clutch shaft snapping (which i saw with some light and extended mirror)

When I had the entire system replaced under warranty at a different MB dealer, they mentioned the clutch as the failure point. Would love to know the real facts... Just thought I'd share my experience with you

LILBENZ230

Gah I really hope my A/C system doesn't experience this.

Glyn M Ruck

These are swash plate compressors. There is NO clutch!

jdsho

OKAY THEN, so technically, no "clutch". My car isn't in warranty anymore.
The repair shop that completed the repair work after my accident--is it possible that they are to blame for this part not working properly?

This is the SAME repair shop that didn't connect my intercooler properly (so they say) and that is why my car spewed transmission fluid all over the road 2 weeks after I picked it up (lol). Everything has been working fine since the repair--other than that. No problems, shakes, rattles, odd driving behavior--just this AC issue.

Any recommendations? I don't want to spend a lot of money (that I don't currently have at the moment)....my insurance company is considering opening up the claim again in order to get the AC job done completely. That may work.

The repair shop wants me to replace the interior AC switch. They quoted me $460....I've seen them on eBay for about $150. Still don't know why they told me I needed that when I heard all that noise under the hood..

LILBENZ230

The noise under the hood would make no sense if the interior A/C control panel went bad.

jdsho

Ya! That's what I'm saying. They think I'm really stupid...there's no way it is the switch--everything else works---defrost, temp control, blower speed, air direction, recirculation button, etc.

I have a print out of the parts replaced...Here's a list of the AC ones that I could spot out. I am thinking this is the repair shop's error--they don't seem to know what they are talking about. Sad, because its one of the best ones in my area. It took 54 days to get my car back...and it was just a little front end damage LOL. horrible.

Parts Replaced:

cooling radiator
cooling fan module
R LWR cooling mount
L LWR cooling mount
cooling drive belt
air cond condenser assembly
evacuate & recharge A/C
Air cond ambient temp sensor
Air cond seal
air cond mounting frame
air cond air guide
air cond receiver /drier pipe
a/c wire harness (existing)
air cleaner assy
air cleaner boot


Lots of a/c stuff...their work is guaranteed for 10 years...do I need to go back and demand anything? I don't know much about cars--especially these. thanks for helping out guys.

Glyn M Ruck

If the aircon is not getting cold it has either lost all it's gas or the compressor is not pumping. They must check that the swash plate activates & the compressor pumps & that the system is fully gassed.

As Matt says - It's unlikely to be the cabin controller.

Try to get insurance to reopen the file. Something has not been repaired properly. I see the compressor was not replaced.

jdsho

Hey Glyn.. thanks for the info..
they said the AC cooling fluid is full, since they recharged it.
they also said when they ran star diagnostics that for the switch it said "recommend replacement". I think that is simply a lie since they have no idea what they are doing lol

Do you think a front-end accident would be able to damage the compressor? i hope so ! I need to make my case with my insurer. :P

Glyn M Ruck

Yes - the aircon compressor is usually one of the first things after the radiator & fan to get damaged in a front end knock.

acr2001

I'm pretty sure your compressor is toast. Unless you started beating on the switch in anger, there is no way your HVAC module just magically became damaged at the same time. I'm guessing the A/C light does not come on when you press the button? If that's the case it is a normal behavior when the system detects a loss of refrigerant. Are those dumbasses faulting the switch because it isn't lighting up? If they knew how to properly use Star Diagnostics they could get you a printout of the errors being thrown by the HVAC system.

jdsho

I think they are simply looking for an excuse not to work on my vehicle--they went from engine bay to interior; something, they feel, would not be directly related to the accident.

The light on the switch (AC) d o e s come on when pressed! the usual, slight decrease in rpm does not occur any more however (post-pop! sound)...I really feel like it is the compressor as well..

Thanks for all the help guys. i talked to the insurance claims adjuster today and he said "Take it to Mercedes Benz. Pay for any diagnostic work--if it is the compressor, I'll add it to your prior claim. That would have most likely been damaged from your wreck".



YES! right? yesss! how much does diagnostic work usually cost? eeghh

Glyn M Ruck

Right - good observations. If the light comes on you have full refrigerant pressure - there is a protection circuit to protect the compressor should the refrigerant leak. If the engine does not see that slight decrease in RPM when you turn on the aircon before the ECU can correct for the load then the compressor is not pumping and loading the engine. Almost certainly compressor or related trouble. At best the swash plate actuator might be damaged.

Your insurance should pay for the diagnostic work if the outcome is crash related which I'm pretty sure it is.

jdsho

first of all--I'm glad to know the RPM thing is normal. I wasn't sure if it was or not. It was always very slight unless I had just started my engine on a cooler day..

Taking it to the local stealership tomorrow. I can't wait to get all this done! Luckily, the insurance company will reimburse me for the diagnostic work. My local dealership is kinda terrible (lol, my luck right)..they have some secret reason to charge more than more prestigious dealerships like the ones in San Francisco nearby etc.

Thanks for your help Glyn! I'll post the results of the diag. work soon

jdsho

Monday is the big estimate-- my dealership wants $241 for an estimate! blah

that is terrible!

jdsho

it's the compressor. GAH! so terrible

Glyn M Ruck

At least you know what's wrong.
Good luck!

krisv420

Could anyone tell me why my power steering seems to feel dead/hard if i don't drive the car hard.. Or if i don't have the AC on.. Some parts have a mind of there own.. I need a real tech to drive my car to tell me all the issues