C180K 2004 M271 Timing Chain checking for stretch

[ChrisP77]

After some advice, car has started doing a cold start 2-3 second rattle (Tho not every cold start) its on 96k miles 2nd owner had FSH up till I got it and been regularly serviced by my self merc oil filter and same oil as merc use on FSH. Looking on the forums looks like timing chain could be culprit it's making the noise in the morning first start but if left for 3-4hr it starts quiet. It's never been changed and I've not checked it since having the cars quite a few years.

Downloaded a few WIS docs on changing the chain via feed in method.

Is there a method for checking chain stretch ? How do I do this

 

[Dodipops]

Rocker cover off, turn to TDC look at the marks on the cams, you’ll likely find they’re not exactly in line.

If it ain’t been done though I’d just have it replaced. It will get worse and cause you problems.

 

[Petrol Pete]

Chris , not enough detail in your post regarding which engine you have but if it is the one I am thinking about cam chain/sprocket wear is an issue even with full MB service records.

And you will also hear evidence of the same engine never showing signs of wear in this area . But the general consensus is get it fixed asap as the chain can skip one tooth and the engine will still run (a little rough) then if it skips one more tooth....time call the scrap man to take the car away.

 

[markjay]

The M271 engine in the CL203 didn't suffer from stretched timing chain as such, instead it was the teeth on the camshaft sprocket wheels that suffered premature wear, leading to (potentially catastrophic) timing chain slip.

The remedy is a new timing gear kit, consisting of two new sprocket wheels, timing chain, hydraulic tensioner, and timing chain guide.

That been said, (a) a stretched timing chain is a possible issue on any car, (2) a leaking hydraulic tensioner on the M271 engine will give the appearance of a stretched chain, and (c) oil starvation at the top of the engine can cause 'sewing machine' noise from the hydraulic tappets (is the noise coming from the top or from the front of the engine?)

 

[ChrisP77]

Thanks for reply's.

I tried to get a video of noise been sat 24hr and first time in days its not done it!!!

I will get the rocker cover off in the next few days and check the alignment marks and condition of the sprocket teeth and report back. Based on fact I've never checked them better to play safe.

 

[ChrisP77]

Seem to remember when fitting a new battery a couple years ago issues with the w203 (its the 1.8 Kompressor CL203 2004 older dash think it change shortly after) Sams blowing, I did the 2nd power source while changing battery back then. If the alternator has to be moved for tensioner access then the battery needs disconnecting what's the procedure to disconnect re connect to not damage the sams?

 

[BlackC55]

If its rattling then get it changed asap. They snap often.

You will need special tools to do the job correctly with minimum risk. Buy the chain, tensioner and cam sprockets from MB ONLY. Cheap ebay kits are no good. I was supplied a kit once and it was shite. Ended up having to do the job twice.

 

[ChrisP77]

Well spent a few hours on it today got the cover off and sprockets look absolutely fine no worn/missing teeth , chain is tight across the top guide practically no movement trying to pulling upwards just about able to create a gap one end. The timing marks on the two cams and crank all line up with maybe 1mm out so all looks good there. Thinking now maybe noisy tappet.

 

[BlackC55]

Lets see some pictures of it.

 

[Stocious]

What mileage on the chain?