Worrying knock

steveuniq

Member
Joined
Jan 26, 2003
Messages
46
Location
South Yorkshire
Car
2011 C180 Sport
Whilst my car was ticking over on the drive this morning, i noticed that it had developed a slight knocking nose.

My car is a 94 C220 manual.

It cannot be heard when inside the car, but when outside it can just be heard, and with the bonnet up is very noticable. It seems to be coming from the front of the engine, and is a chatter/knock that increases with engine revs.

I am maybe thinking water pump, but any other ideas? If so any ideas on the cost?

If its really bad news, break it to me gently!
 

jimmy

MB Enthusiast
Joined
Aug 8, 2002
Messages
2,316
Location
Northamptonshire
Car
Discovery 3 TDV6, Discovery 300TDi - Plaything!
An easy way to tell if it is the water pump is to remove the drive belt and run the engine without it, if the noise is not there it is most likely the water pump or possibly the belt tensioner pulley.
 

Mark300SL

1962-2010. Gone, but not forgotten.
Joined
Jul 21, 2002
Messages
1,641
Could be an exhaust manifold blow - sounds like a ticking and sometimes goes away when its hot and everything has expanded

Mark
 

martyz

MB Enthusiast
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Joined
May 14, 2011
Messages
2,436
Location
New Forest
Car
ClK 209,190E 201.
Front of car n/s on the chassis member is a solenoid valve,which chatters away
allowing petrol vapour from the charcoal canister into the inlet manifold to be burnt.
Sounds a bit like a tappet,quite normal,it's called the purge valve.
 

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