93 Lincoln Mark8 83k miles, couple oil questions.

Messages
6,185
Location
Texas Hill Country
A buddy of mine has a nice 93 lincoln mark8 with 83k miles. He didn't know better, so he was using valvoline oil for the first 75k then he switched to valvoline maxlife for the past few oil changes. The good thing is that the oil has been changed regularly (3-5k), the bad thing is that the engine is very varnished, and I bet it has some sludge in it. I was talking to him about oil and he asked what he should do. I recommended that he do an auto-rx treatment to get the gunk out of the motor, then switch to a good quality dino (havoline or motorcraft brand) He uses a 10w30 weight oil in the car year round. I also told him that I would use mobil 1 10w30 in a motor like that after the auto-rx treatment, and it will help to clean up the motor alot. the motor is the 4.6L DOHC v8 (basically a cobra motor minus a few parts inside) I'm getting him on the right track. Anyone have any additions to my recommendations?
 
Messages
323
Location
Minnesota-South Dakota
Well, the good thing...that engine doesn't wear much. At any rate, with 83M, it should still be just great, with what he has been doing. The MaxLife is a goog product, which may have already started a cleaning on the internals. If he doesn't mind spending a little $, the AutoRX treatment would be great! If there are any seapages or leaks, I would recommend staying with the Valvoline MaxLife or better MaxLife synthetic for OCI's, until the leaks stop. At that point, Mobil-1 is a very good choice, and from my personal experience, that engine likes Mobil-1 5&10W-30, preferrably the 5W-30, unless he really drives it hard. Good Luck!!!
 

TC

Messages
1,644
Location
California
Running a diesel lube for a few thousand miles may help clean things up some. WalMart has Motorcraft 15w-40 for about $1.46, which is probably the least expensive diesel lube I know of. A bit thick for much of the year in New York, but perfectly fine for the upcoming Summer months. Diesel lubes (which are actually mixed-fleet gas/diesel lubes) have higher TBNs (long-term cleaning ability) than either syns or conventional oils.
 
Messages
127
Location
Greenbrier, Tn
Being as that 4.6 is a four cam OHC design and my experience was that they historically develop a knock from the hydraulic timing chain adjusters needing to pump up on the first start of the day I would be reluctant to use anything heavier than the specified 5w30. I would do the AutoRX treatment and then either use Mobil 1 or possibly Motorcraft 5w30. I had good success with the Motorcraft in my 5.4 mod motor. I have posted a UOA of it. However when I had my Mark VIII I did use Mobil 1 so I could extend the drain interval to 6,000 miles safely. That oil filter was a pain to get to and the car was hard to get on the ramps I had without dragging the front bumper. That motor will last forever though. Good luck either way.
 

TC

Messages
1,644
Location
California
Based on Seldont's comments, I still believe a mixed fleet diesel lube could be of benefit, but perhaps the factory weight would be more appropriate, even for a temporary Summer experiment. Since the vast majority of these lubes are 15w-40, you might try a store that caters to trucking fleets as well (such as many Napa Auto stores) and see if they carry a diesel 5w/10w-30 lube. These are rarely found at the typical chain stores.
 
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