vito w639 engine knocking

[kingding1976]

hi all ive just got a vito 53 plate w639 and it has a engine knock
the van seems to drive ok apart from the loud knocking noise which i suspect is the piston / shell bearings. has anyone else come across this issue or knows a way to confirm this as the problem. thanks

 

[StMarks]

Fwiw the description "knocking" is subjective. You may as well be asking; how long is a bit of string IMHO
I suggest that (if you want worthwhile advice on this) you could do a short video clip of the engine running & post it on Youtube, then post a link for people to make their observations.
That was what I did when I had a Knocking noise on a (638) vito a few years ago.
Linky; http://www.mbclub.co.uk/forums/engine/144097-vito-110cdi-tapping-sound.html

Hth, good luck.

 

[kingding1976]

hi thanks for the reply . i think i may have actually looked at your post after i wrote this and although my van is the newer shape rwd model the noise is the same as yours on you tube so i think i may have piston slap. i will try to do a short video once this rain stops. thanks

 

[StMarks]

hi thanks for the reply . i think i may have actually looked at your post after i wrote this and although my van is the newer shape rwd model the noise is the same as yours on you tube so i think i may have piston slap. i will try to do a short video once this rain stops. thanks

Actually, I now have a 2007 639 too (same shape as yours), I just felt that the thread would illustrate my point mate.
If it's piston slap, then it is usually louder when the engine is cold & decreases as the engine warms up (thereby expanding to take up some of the slack). That piston was so bad that it stayed pretty noisy even when warm.
Incidentally, I trust that you are aware of the "quality issues" of Mercs' between about 97 - 2005, the Vitos especially are terribly affected by tinworm. The reason I no longer have my little 638 is because I discovered it had terminal rot (rotting from the inside out). The early 639's are apparently equally susceptible, and you are well advised to select a 2006/7 onwards version if possible as that is when the galvanised ones were introduced.
So before you invest the money, time & effort that I did on my engine, perhaps you should take a very through inspection of the structure.?

Sorry if this reply comes across as a little negative, it's just that if someone can learn from my mistake, then it may not have been such a waste after all.