maverik259

So ya engine ticks like nuts at start-up and its quite annoying especially when it makes my car sound like a diesel...I've search around on here and google in general and nothing specific to our engine/chasis...i have the m271 btw. Thanks for anyone who's experienced this and fixed it (hopefully).

Moreira_C230

I have a very similar problem, however I have the M272, but my issue happens to be a pretty significant exhaust leak just before or after my left primary cat. Just an idea.

maverik259

i dont think its an exhaust leak only because it seems to come from opposite side of the headers...plus i had an emissions leak about a year ago and they did a smoke test and i think it woulda shown a leak...

Glyn M Ruck

RU sure it's not the purge valve?

samaritrey

+1 very annoying

maverik259

yep am aware of the purge valve noise but its closer to the engine if not the engine itself...my purge valve is brand new and doesn't really make much noise anymore...but ya that was the first thing I checked

LILBENZ230

Perhaps you should record a video? My M271 has always sounded like a diesel.

Glyn M Ruck

+1^ - you might have a buggered hydraulic lifter.

maverik259

ya thats exactly what it sounds like...a dang diesel!

wippet

Sometimes the timing chain is noisy for the first few second.

Glyn M Ruck

If the timing chain is noisy for the first few seconds after start before the oil pressure comes up it's time for a new chain & tensioner inspection & repair (chain is hydraulically tensioned). This is when a chain in the M271 can jump a tooth with dire consequences.

Note that the noise can also be cam adjuster rattle requiring deburring or replacement. Careful diagnosis is needed.

LILBENZ230

The M271 had a service bulletin regarding cam adjuster rattling at start-up. My car had this happen at 30-something thousand miles and was fixed under warranty. But that's not the same thing as a ticking noise that goes on constantly.

albabenzi

Hello, is the purge valve supposed to tick so loud? Does that indicate normal operation or maybe indication of it possibly going out?
Thanks!

Glyn M Ruck

The purge valve is supposed to be quiet. It will last a long time ticking loudly but if you are like me you would replace it for the silence.

albabenzi

Thanks for the quick response. i've researched many threads and i see you have helped many with your knowledge. Thanks again
I might very well replace it. My 2004 C240 has 126 K miles on it. I am trying to do as much PM to it so it will last a while.
Happy New Year

Massimigliano

Hi I have a knocking noise in my C300 the purge valve has been replaced... when I touch the fuel lines they seem to be thumping at about the same frequency as the knocking. Is there something that is causing this or should this be the norm? Thanks, Massimo