I have a 420SEL with a little over 320K on it. Runs like a top except for some tranny problems.

I read a thread about replacing the timing chain and upper guides. I took a look. The guides need it judging by the dark brown color. Chain is tight. Did not check TDC.

So I am ready to replace the uppers, chain and tensioner. But what about the lowers? I saw one post that said they were good till 350K. Another said 500K. If it is a job I can do I would rather err on the side of early replacement and save my engine!

I can't seem to find anything on replacing the lowers. Does anyone have anything on that procedure? My factory service manual doesn't seem to have anything in it about timing guide replacement.

Many thanks in advance to all you wonderful people. I have already learned so much from this forum. (Made me decide to keep the ol' girl)