Double Style Timing Chain
 

I Own A 1991 Mecedes Sel 420, Do You Still Need To Replace The Double Style Timing Chains Or Is It Only For The Single Style Ones That Need Replacement. If So At What Mileage Should I Replace It At. Thanks

Typically, the chain guides need to be replaced due to wear. With the cam covers off, rotate the engine clockwise until the notches on the camshaft meet up with the notches on the cam towers. Read the number on the crank damper, use chalk to make them visible. Depending on the number, the closer to zero the better, start by rewplacing the chain guides. If the offset is still high, the chain will need to be replaced. The sprockets may need to be replaced too if the tips are sharp instead of flat on the ends.

I'll post a link later.

The MB rule of thumb for replacing your timing chain and guides is 10 years and/or 100K miles. The chains seldom break on their own but the plastic guides become brittle, break, and drop into the chain system and cause major problems. And as long as you are going to all the trouble to replace the plastic parts you might as well put in a new chain too. They are not expensive.

Chain life varies so much on MB motors there is no rule of thumb, or factory recommendation, on changing the timing chain. To change a timing chain just because it has reached 10 years or 100k miles is an outdated notion. It would be foolish for example to change a 104 motor timing chain at 10 yrs/100k miles. It's not a question of how much how much it costs. Changing a good unmolested factory timing chain is more likely to create risk than to mitigate it.

600sl hydro/ADS suspension
 

600sl hydro/ADS suspension

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The 1995 sl600 in question hasn't had a road trip in over a year. It has been stored in a climate controlled setting and ran/moved about 10 miles in the last year.

The front is now down to where the airdam is about three inches off the ground. Rear is still up so it looks like a funny car or a near sighted ant eater.

I haven't done anything but ran it checked for leaks and confirmed that the screen is clean. The fluid is fresh and reservor is still where it's been since fluid change three years ago.

Can someone step me though a trouble shooting plan and a way to bleed the system? Thank you for your help in this matter.

How about starting your own thread
 

Short Turtle, your question has no bearing on the trust of this writers timing chain question.

deanyel said: Chain life varies so much on MB motors there is no rule of thumb, or factory recommendation, on changing the timing chain.
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I should have said that the rule of thumb of 10 years or 100K miles applies to the 420/560 series of engines. At least that is what has always been conventional wisdom on this board in the years that I have been a member. And as I mentioned in my original post, the problem usually occurs not from a timing chain breaking but the plastic guides failing and dropping into the chain mechanism causing the engine to jump time.

I agree w/deanyel. I see no need to change the chain on my M110 engine. It's 30 years old, 207k on the clock, and when I adjusted the valves 3 weeks ago, the timing showed just 2 degrees off. Ever case is unique.