Cam chain

[Twinwasp]

I drive a 1997 C250 turbodiesel with 142,000 miles on the clock. The cam chain has not been changed. I understood it would last the lifetime of the engine. I was watching "Wheeler Dealers" working on a 1970s 500 SL and they said its chain needed changing at 100,00 mile intervals. Please can anyone advise me whether my chain need changing, or has technology moved on since the 1970s. Many thanks.

 

[LostKiwi]

If it's not noisy it doesn't need doing.
My E240 is on 160k on original chain and it's fine.
My 1993 500SL is on 145k on original chain and is fine.
My 2004 Smart is on 145k on original chain and is only just starting to get noisy (and these are known to wear chains before 100k miles).

 

[Twinwasp]

Ah - that's fine! Many thanks for the prompt and helpful reply...

 

[Jim2]

In my first Merc, an 2010 Eclass, 200 CDI, OM651 engine, the timing chain had been done at about 120'000 mile's, so it was one thing that I did not have to worry about I had it from January 2018 until August 2020, Great car, had to do some work on it, but no problem,
Now it's replacement ( 2014 E Class 220 ) has a very good MB service, but no record of any timing chain work done, and it's at 130'000 miles, and absolutely no unusual sounds at startup. When these chains start to go, do they normally gradually get noisier at start up, or can they suddenly just snap? Can they be checked in situ for chain / guides wear? I presume that for a full replacement job, guides, gears and chains it's an engine out job? Worst case scenario, what's that likely to cost ? Rough estimate will do.

 

[LostKiwi]

They normally get progressively noisier.
Depending on the engine there are ways to check by setting the crank to a particular place then inserting a pin in a hole in the can sprocket. If the pin won't fit slowly move the crank till it does and measure the number of degrees it had to be moved. There's usually an acceptable spec.
On an OM651 it may be different as the sprockets are at the back of the engine (stupid idea done to get bonnet lines lower). These are changed by splitting the chain, joing the new one to one end and carefully winding it through before splitting the new chain from the old one and joing the two ends of the new chain.

 

[EmilysDad]

..... These are changed by splitting the chain, joing the new one to one end and carefully winding it through before splitting the new chain from the old one and joing the two ends of the new chain.

I've heard of that on here before, but IMHO it's not a good idea to put a new chain on to worn sprockets.

I doubt that just a new chain on my Roadster's crank & cam sprockets would've been a good idea or lasted very long. (It was EmilysMum's at the time

 

[LostKiwi]

I've heard of that on here before, but IMHO it's not a good idea to put a new chain on to worn sprockets.

I doubt that just a new chain on my Roadster's crank & cam sprockets would've been a good idea or lasted very long. (It was EmilysMum's at the time

Yeah that's pretty goosed.....

 

[EmilysDad]

Yeah that's pretty goosed.....

They were .... the chain tried to saw its way through the cover. We/she'd not had the car that long at the time, she wanted the car & I'd not done any proper homework on the cars in general

 

[Jim2]

Thanks Lostkiwi and Emilys Dad.... Yeah, that's one well worn gear all right,,that had to be making a racket. I think for now, I'll drive on, and if I happen to be anywhere near my local Indy, I'll drop in and let him have a look. This Covid -19 is playing hell with all kinds of planning, and while we can travel in general, there are quarantined area's, so have to wait and see. But in general, the engine is running as sweet as a nut, and driving beautifully.

 

[ajlsl600]

Om651 bit of a lottery in many ways, I think changing oil at half intervals and not using stop start best way of avoiding premature timing chain expenses
Also fixing inlet manifold flaps in open position seems a future expense avoided

 

[Uncle Benz]

The om651 gives a good indication of chain and sprocket wear after an oil and filter change. While the new filter fills you can hear the chain rattle. A good one is barely a chirrup. A worn one, well, it’ll tighten the scrotum of a time-served mechanic

 

[Jim2]

The om651 gives a good indication of chain and sprocket wear after an oil and filter change. While the new filter fills you can hear the chain rattle. A good one is barely a chirrup. A worn one, well, it’ll tighten the scrotum of a time-served mechanic

Still 160 days to oil and filter change Uncle Benz, but I'll bear that in mind. In days of old, this was a common noise at start up, even between changes. Used to quieten down then as the oil circulated, and was considered "Normal "... LOL oFten remember after an oil change, disconnecting the main lead from the distributor for a few seconds to allow the oil to circulate, especially if the owner was looking over my shoulder..

 

[ajlsl600]

The om651 gives a good indication of chain and sprocket wear after an oil and filter change. While the new filter fills you can hear the chain rattle. A good one is barely a chirrup. A worn one, well, it’ll tighten the scrotum of a time-served mechanic

Wonder in if I should fit my pre lube kit to the om651. Gives system oil press to motor at ignition on.

 

[Jim2]

Om651 bit of a lottery in many ways, I think changing oil at half intervals and not using stop start best way of avoiding premature timing chain expenses
Also fixing inlet manifold flaps in open position seems a future expense avoided

Thats a good tip ajlsl600, Prevention is always better than tne cure, I'll bear that