I’m no stranger to the clickity-clackity sounds the M112/113 engines make at idle but today for some odd reason it’s BOTHERING me. Of the Crossfires I’ve owned, only two had it to the point where it truly annoyed me. Let’s walk through the possible issues that plague some of these engines, according to the interwebs…

a. Noisy lifter/frozen lifter (highly likely)
b. Stuck or partially stuck rocker arm (likely)
c. Oil pump chain slack, causing the oil pump chain to slap the timing cover (more of a V8 issue)
d. Partially clogged oil passage at the rear of the cylinder head (I’ve read multiple accounts of this)
e. Low oil pressure at idle
f. Other crap, it’s a Mercedes Benz engine after all

The oldest Crossfires roaming the earth are over 20 years old and these engines have been on the roads since 1997, making the oldest living versions approaching the 30 year mark. Numerous articles online document the clacking and tapping noises at idle, but it’s hard to find someone post something useful with a clear resolution or solution to the issue.

I would be okay be with the sentiment being “it’ll run like that forever so just deal with it”, but there’s gotta be more to the story right?

my question is, have any of you spent time trying to diagnose the noise and come with a solution?

 

I've have, what to me, sounds like valve clatter, but when I use a stethoscope to listen to the valves, they sound find. I haven't found out what's making the noise, but I've read that it might be a solenoid in the EVAP system. Maybe that's symptom is part of bullet f. above.

 

It's not.

1) Valve noise happens, generally, every other revolution of the engine as the valve operates and varies with engine speed.
The EVAP solenoid you are thinking of is on the fender wall, near the brake controller, and it activates at a steady rate, regardless of crankshaft speed.

2) I know Cliff personally, I can assure you that Cliff knows the difference.

 

Maybe, earplugs? Sorry, had to do it!


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Xf , excuse me resurrecting an old thread but as part of my spending hours researching the m112 engine ticking, of everything I’ve read your 2015 thread which I’ve just come across way down the search list is definitely the most succinct and articulating where my own thoughts had gotten to. Was almost a relief to hear someone else articulate - what surprised me though was the lack of take up from a response perspective. Is a consistent thread on Mercedes forums and chat but less so on Crossfire.
My thoughts were are your list above, with one other possibility of exhaust manifold leak. I can’t believe that your thread starter didn’t start an avalanche. Did you ever find out/get there. I’ll happily exchange my thoughts ad nauseam as I continue to persevere.

 

I don't know, Svengoolie sounds happy ticking away