So I've got a 1988 420SEL that has a rattle on cold start. Lasts maybe 1 second at most.

Sounds to me like a timing chain rattle, though the car only has 75k miles on it - isn't this supposed to happen at 120+ on these engines?

Could this be a broken guide, rather than a stretched chain, or do they fly off (into the valve gear!) as soon as they break?

Anyway, I'm going to go and pop the valve covers off and see what it looks like in there, but what am I looking for? How do I tell if the chain is too loose?

And what the hell is it that is actually making this noise? Chain banging the guides around, guides slapping the valve cover?

Any advice from those of you who have been in there greatly appreciated!

Thank you.

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1988 420SEL