I bought a 1995 Honda Accord 4 cyl 3 months ago with 133k miles on it. I'm learning that the previous owner had evidently never heard of maintenance, although he put on a good show.
When I got the vehicle, the oil sticker in the window showed I had more than 2,000 miles left before the next oil change. I'm sure this was a 3,000 Iffy Lube type service.
The minute I got it home (after stopping by the parts store), I dropped the oil, replaced the ORIGINAL plugs, and changed the air filter.
The oil was NASTY black. Not the worst I have ever seen in a vehicle, but certainly not clean as it should have been with more than 2,000 miles left on a 3k mile OCI.
I dumped in 3-1/2 quarts of oil and 1 quart of Marvel Mystery Oil. Within 50 miles it was nasty black again. I ran it for 500 miles and changed it again. I ran this oil for about 1700 miles and changed it, adding 1/2 quart of MMO and running it 1800 miles.
I've changed it again and used Advanced Auto 5W30 for this final "rinse" phase. I'll run this for about 2,000 miles, and dump it.
I'm gonna run Havoline 5W30 with a PureONE or WIX filter on it. I'm running Havoline because Advance has it on sale in jugs right now and I'll buy 4 or more of them.
I pulled the valve cover this weekend and it looks good. No sludge, some varnish, but I plan on doing 2 more MMO cycles in 2006 with this car.