Regarding the T-chain, gas and diesel engines are different. I will not be surprised if the 300SDL still has the original chain. I saw many 617 high mileage engines still had the original chain. I have not seen enough 60x engines to tell about their chains.

A good independent Mercedes shop is the way to go if you want to save money. I cannot comment on the $1200 price tag without knowing the details of the job. If you have to change every thing inside the timing chain housing, it will be expensive. It is a $8000+ engine, you just cannot afford to make mistakes when you perform the task.

David

Both of my Benz's have around 170k miles and they both run great. I have been hearing that the timing chain should be changed at 100k. Should I change them even though I am having no problems.

Are there any preliminary signs that I should know about so I will know that the change is going bad?

How long do these gas engines last? 300k? 400? WHat happends after that, just rebuilding????

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'89 420 SEL
'90 300 SEL
'84 300 SD (sold it)

Mattsuzie,
There's probably a way to check the chain stretch on your SEL's that is equivalent to the method described by LarryBible above. I don't think there's a reasonable way to just "know" that it needs replacement other than actually getting to the chain and checking the stretch.

- Nathan
'83 240D, 250k miles

MattSuzie,

It appears that you have two different animals as far as timing chains go. Your 420 is probably a V8 which has unique in this area as compared to the six in your 300. I didn't notice what year your 300 is. If it is an M103, don't worry about the chain. If it is a twin cam six, it may be more like the V8, that is, the rails are the culprits to be observed. On the V8, the plastic rails break and cause havoc. I would expect a twin cam six to be similar. Hopefully one of the pro's will comment for you about your specific engines. Some engines like the M103 you don't worry about, and others like the V8's you stay all over.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles