I just purchased a 90 560SEL with 361000 miles. I have records for the last 160000 miles or so. It had the timing chain and guides replaced at 190000 which means it is well overdue. Would it be OK to replace the upper guides and the chain and not do the 2 lower guides? I really don't want to pull the timing chain cover as that requires removing the heads to do it right. If I have to do that, I will just pull the engine. I can't find any record of the water pump being replaced. Do they last that long? Any other recommendations other than timing chain, guides, w/p, and all fluids and filters. Car runs great. Has been serviced every 3000 miles like clock work.
Thanks
Paul

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84 500 SEL (307,xxx miles)