A class W168. Engine rattle when cold

[bradspau]

Hi. I have a 1999 A160 (w168) with an annoying engine rattle on startup that lasts until the engine is at normal running temp.

Sounds like a tappet rattle, but don't these have hydraulic tappets (?). Noise gets louder on acceleration and almost completly disappears when the engine is warm. Oil and filter changed (mobil 1 fully synth) but no difference. Sounds like it's coming from the top of the engine area.

Any ideas, as I want to sell this car, but need to get this sorted first

Thanks.

 

[grober]

Sounds as if one of the tappets is not pumping up with oil right away. Once the engine heats up the clearance decreases/tappet gets oil and the sound goes away. No easy fix other than what you have done already. There are some special flushing oils for this purpose out there which you might want to try? the other possibility is a worn timing chain tensioner ?? you might want to PM this guy who is an expert on the A class model. http://www.aclassinfo.co.uk/mypage.1.htm

 

[BlackC55]

Many 168's do this but it lasts only a second or two.

In your case it sounds like a poorly tappet or chain tensioner but most likely to be the tappet

 

[amliddle]

bradspau,

Did you ever resolve this issue?