Timing Chain

[Chefey]

I am in the process of buying a 2008 SLK 200 Kompressor, milage is 91,000 miles. Is this worth buying if timing chain has not been changed..
Look forward to your replies.
David

 

[pcthrillrider2]

thats the M271 engine renown for timing chain issues, start car from cold if it rattles walk away

 

[markjay]

I am in the process of buying a 2008 SLK 200 Kompressor, milage is 91,000 miles. Is this worth buying if timing chain has not been changed..
Look forward to your replies.
David

Can you not budget for timing chain and sprockets inspection? They may be in good condition, you never know.

 

[Bayleaf]

Is the chain on this engine at the front or rear.

 

[markjay]

Is the chain on this engine at the front or rear.

Front

 

[Bayleaf]

Front

Good, that makes a big difference to the labour charges unless the engine still has to be removed.

 

[slade1]

Chain sprocket change on M272 V6 was around 2.5K£ 10 years ago.

 

[W1ghty]

About £1200-1400 for the M271 I think

 

[markjay]

About £1200-1400 for the M271 I think

Correct.

That's IF the sprockets are worn, in which case you'll need two new camshaft sprocket wheels, timing chain and guide, and hydraulic tensioner (plus labour).

But if you remove the camshaft cover, and the sprockets are fine, the chain tension is fine, and there's no rattle at startup (I.e. the hydraulic tensioner isn't leaking) then you can put the cover back and the car will be good for a few more years. There's no prescribed change interval for the timing chain on the M271 engine. If it's fine, there's no need to change it.

These things only fail when worn. If they are not worn now, it will be a long time before they wear and eventually fail.

 

[pcthrillrider2]

Correct.

That's IF the sprockets are worn, in which case you'll need two new camshaft sprocket wheels, timing chain and guide, and hydraulic tensioner (plus labour).

But if you remove the camshaft cover, and the sprockets are fine, the chain tension is fine, and there's no rattle at startup (I.e. the hydraulic tensioner isn't leaking) then you can put the cover back and the car will be good for a few more years. There's no prescribed change interval for the timing chain on the M271 engine. If it's fine, there's no need to change it.

These things only fail when worn. If they are not worn now, it will be a long time before they wear and eventually fail.

my m271 rattled on cold start for 1-2 secs

 

[slade1]

The failure rate, I believe, on M272 is around 2%
The engine management light will show to give you a warning of a problem.
"If ain't broke don't try and fix it"

 

[markjay]

my m271 rattled on cold start for 1-2 secs

This is normal, because it takes a few seconds for the oil pressure to build up inside the hydraulic timing chain tensioner, and for oil to reach the hydraulic tappets at the top of the engine.

The issue with a leaking tensioner is that the oil drains back into the sump soon after the engine has been turned off, which leads to startup rattles also when the engine is not cold.

This is also why, if the sprockets are worn, the chain is more likely to 'jump a tooth' (causing two pistons to hit the valves) during a cold start - because this is when the hydraulic tensioner is not yet fully supporting the timing chain. However, if the hydraulic tensioner is also leaking, then the catastrophic damage might occur during engine startup even when the engine is not cold.

 

[johncherokee]

My clc200 had the timing chain changed at 89000, now done 155000, still sounds quiet and the timing is ok. If it doesn’t need changing until 18000 then I have got another 18 years before it needs doing again. I will have stopped driving by then, I don’t think I ought to be driving past 90.