Timing Chain

[BENZE220AMG]

I am in the midst of purchasing a 2008 SLK 200 Kompressor with a mileage of 91,000 kilometres. Is this purchase advisable if the timing chain has not been replaced?
I anticipate your responses.

[MidnightMarauder]

The M271 engine is notorious for timing chain problems; if the vehicle rattles at cold start, it is advisable to refrain from purchasing.

[bentleygt77]

Is it possible to exclude the budget for the examination of the timing chain and sprockets? They might be in satisfactory shape; one can never be certain.

[CelestialSeeker]

Is the chain located at the front or back of this engine?

[bentleygt77]

Facade

[CelestialSeeker]

That significantly impacts the manpower costs, unless the engine must still be extracted.

[xsports]

The cost of changing the chain sprocket on the M272 V6 was around £2,500 a decade ago.

[Starcar2022]

Approximately £1200 to £1400 for the M271, I believe.

[bentleygt77]

Accurate.

That is contingent upon the sprockets being worn; in such an event, two new camshaft sprocket wheels, a timing chain, a guide, and a hydraulic tensioner will be required, in addition to labour costs.

If the camshaft cover is removed and the sprockets and chain tension are satisfactory, with no rattling at beginning indicating a leaky hydraulic tensioner, the cover may be reattached, allowing the vehicle to function well for many further years. The M271 engine does not have a specified replacement period for the timing chain. If it is satisfactory, no alterations are necessary.

These items only malfunction when used. If they are not used today, it will be an extended period before they deteriorate and ultimately collapse.

[MidnightMarauder]

My M271 had a rattling noise at cold start for 1-2 seconds.

[norbury.brook]

The failure rate of the M272 is around 2%.
The engine management light will illuminate to indicate a malfunction.
"If it isn't broken, do not attempt to repair it."

[bentleygt77]

This is typical, since it takes several seconds for the oil pressure to accumulate inside the hydraulic timing chain tensioner and for oil to reach the hydraulic tappets at the engine's apex.

The problem with a leaky tensioner is that the oil rapidly returns to the sump when the engine is shut off, resulting in starting noises even when the engine is not cold.

This explains why worn sprockets increase the likelihood of the chain 'jumping a tooth' at a cold start, which may result in two pistons colliding with the valves, since the hydraulic tensioner has not yet completely engaged to support the timing chain. Nonetheless, if the hydraulic tensioner is leaking, catastrophic damage may ensue upon engine starter, even if the engine is not cold.