Engine rattle and idle speed questions....

[marcus8228]

Hi peeps,

i have recently chanced my arm at an E bay W202 c180 sport see post below.

http://www.mbclub.co.uk/forums/new-member-introductions/203404-ive-done-again.html#post2232168

I knew it had issues but hoping to find the cause - so hopefully you guys can help.

Firstly, what should the engine idle at? As i think 500 - 600 rpm seems kinda low, too be fair i haven't checked what my W211 idles at so haven't compared yet.

Also the engine at idle is really rattling like a can, until you get the revs at 1200rpm then runs sweetly.

Drove it today, pulls cleanly, kickdown works like it should, as does the cruise and all electrics - its just this engine rattling noise at idle

Any ideas?

Thanks in advance

 

[marcus8228]

Will try an post a sound clip tomorrow if i can.
Kinda sounds like this... https://www.youtube.com/watch?v=XuwUU8lC8GQ

 

[marcus8228]

https://www.youtube.com/watch?v=JJrliauR_wY

 

[stwat]

The bushes sometimes fail on the belt tensioner damper causing them to rattle like mad at idle.

 

[John Jones Jr]

Remove the drive belt and start her up.

 

[marcus8228]

JJJ - am i taking the entire belt off or just over the idler pulley? What should i be checking for?

 

[John Jones Jr]

Yeah, take the belt off. It's only a matter of moving back the belt tensioner, I'm sure there is a 'how to' on here somewhere. Then if the noise is gone the problem is with a worn belt tensioner, idler, PAS pump, alternator etc. Basically any part that driven by the belt. On the other hand if the noise is still there you can illuminate all these parts as a possible culprit and concentrate on looking for an engine issue. Don't forget a rattling damper as stwat mentioned, not uncommon.

 

[marcus8228]

Thanks. When i did the video yesterday, i put a long screw driver on top of the dampener and it was vibrating like made. I also listened through the top of it, it wasn't coming from the water pump, seemed to towards the right side of pump ie towards the dampner

 

[John Jones Jr]

Hard for me to judge from your vid. I don't think it's the damper and it seems more like a dry bearing noise. Do remove belt and while you're at it disconnect the damper and inspect the bushes. What's really important is make sure the noise is not coming from the engine itself, the more you run it potentially the more damage you could do.