elargy

I have a 2003 C240 4matic wagon that I bought new in December 2003. It now has 2700 miles (125 when acquired) and has been back three time "officially" and twice to the sales person before I started bringing it in on a ticket. In fact, they kept it for a week and when I brought it back today the ticket was still open. Anyone smell lemon avoidance?

First they replaced the purge valve. Last week they replaced the camshafts and rotor arms. Road tested and said noise still there. And diagnosed it as a harmonic chirp. I really don't want to be the person with a new sound and a new diagnosis. Any ideas? Any similar experiences? Thanks. Lynda

mbtech208

What kind of noise are you hearing? When does it make the noise? Where does it seem to come from?

elargy

Sorry for delay in responding. The sound is a constant ticking sound, like a metronome on steroids or diesel engine, although I think it's even louder than a diesel. Just got the car back and it says, "removed drive belt and noise was still heard. Inspected for loose exhaust parts. All OK. Noise seems to be coming from inside the engine. R&R both valve covers and rocker arm brackets. Found camshafts worn."

I bought the car w 125 miles on it and it now has 2,800. How could camshafts be worn?

"R&R altenator and timing chain tensioner. D&A rocker brackets and replaced rocker arms and camshafts. Reassembled components and tested. Slight noise. Called TAC who suggested possible oil pump. Shut off cylinder to check for noise. Still the same. Road tested and heard no abnormal noise."

So my tick has gone from abnormal to normal somehow. Still makes the same ticking noise. It's very loud. Anything I can do about this? Thx.

mleskovar

Even though it's a major inconvenience, annoyance, and waste of time, you must stay on the dealer to correct the problem. They've invested some major work so far and I bet the next step is replace the engine. Just out of curiosity....since the noise is so repeatable...what is the frequency? Higher,
lower, or the same as crankshaft revolution?

elargy

The click is still there!!!

It sounds like valves clicking closed. And yes, I think it does click faster when the engine is pushed past idle.

Could it be the valves clicking closed? This seems AWFULLY loud for a fine german auto.

Originally, I thought it was purge valve return, and it may still be - that clicks too. But it sounds like the noise is coming from engine, and I think its the valves. Odd, it is louder and easily distinguished from inside the cabin, and is difficult to pick out from the other engine noises when the hood is raised.

Any suggestions?

mbtech208

Could be the fuel injectors, they make a clicking sound. That is normal though.

bamberger_1

It is a brand new car. It still under warranty, and is not even 6 months old, and only 2800 miles. You should not even consider to coop neither with the ignorance of the shop nor the sound which is absolutely abnormal. Inside the cabin the V6 engine should not be heard. The repair work and the comments from that shop seem unprofessional. Cam shafts worn???? I would escalate this issue to the next higher customer service level of MB USA, because I think the shop messed up already, and is trying to cover up the mess.

m444

Collasped hydraulic valve lifters can sound like that. It would also wear on the cam.

I would keep after them. Have them show you another two or three new cars with the same sound.

Something is not right, if they replaced the cam, they should replace the lifters also.

Maybe oil is not getting to the valve lifters?

Fuel injector can make that noise, but it is much more mutted. The lifters can be VERY loud.

These are fairly mechanical sounds. A Harmonic Chirp should sound more like a humming bird.