Question for C230 Kompressor Owners - Startup

[xvvvz]

Do any of you experience anything close to the folowing?

At startup and for the first few minutes of running, do you here a slight hissing or "pffft pffft pfft pffft" type sound when accerating normally. You don't hear it while you are idling. The engine has to be under moderate load like when accerating normally from a stop. It goes away fairly quickly as the engine warms up and then stays away until the car sits over night or for a very long time (all day). If I didn't know any better, I would think it was a crack in the exhaust manifold. The car has done this for years. First MB dealer could not fix the problem. Now a second dealer in another city also has tried but hasn't fixed it. This only happens to me in the morning and normally will not happen until the car sits and totally cools down for a long time. The extended warranty is about to run out and I would like to get this problem solved if it is not normal.

I just need some feedback to know whether this is normal for other owners (or not) so that when I go back into the mechanic I can feel confident telling him he really needs to research this a bit more.

Thanks in advance!

[Proven Guilty]

Yes, that's perfectly normal. Some people call this the "warm up" cycle. It uses the supercharger as an air pump to quickly heat the cats and test the oxygen sensors. I think it lasts 60 seconds when the car is cold (parked overnight).

[xvvvz]

Hi P.G. - Thanks for the reply. I knew about the SC being used in place of the air pump and knew that was the reason for the louder "roar" during warmup. I just wasn't convinced that the noticable pffft pffft pfft was also part of the process. The pffft pffft pffft definitely varies with engine speed. Doesn't the SC operate at "full_power_only" during this warmup (hence the reason for the consistently loud roar as opposed to the pfft pffft pffft?

Do other readers hear this too?

Thanks.

[ChristianDK]

I have a "whine/squeak"/mayby a little "pssst" that sounds a bit like a little bird is trapped in the engine compartement. More of a fast "squeak squeak squeak". However it is constant, and most noticeable with the hood closed and when standing on the left side of the car.

Don´t know if it is the same you have. It is a bit hard to tell about noises over the net.

Greetings from Denmark.

[xvvvz]

Mine is definitely similar to the sound of compressed air or exhaust escaping out of something. Not a chirp.

Does your sound occur all the time or just when the engine is cold and warming up for the first few kilometers? Mine is the latter.

Thanks.

[sanf]

the 1st 30 sec or so. the car is just LOUD. then it sits quietly (not really quiet but..)

[benzonline]

I had the same...perfectly normal so I was told.

I let it idle until I hear the kompressor turn off otherwise it makes it kind of sluggish to accelerate because its shoving the air into the engine and the car has difficulty getting a smooth acceleration for about 30 secs into the drive.