Mobil 1 "High Mileage" - opinions?

It's marketing blah...blah.

I would ASSume that any oil marketed as "high mileage" would have extra seal-softening additives, but that is just a guess.

nate

Typically, oils marketed as "high mileage" don't meet some aspect of the new car oil spec. It may be that it doesn't meet the spec to qualify as "energy savings". Or it may have more anti-wear additives then the new car spec allows because new car specs continue to allow lower and lower levels of various additives that can foul the catalytic converter and they are required to warranty the converters for longer and longer lengths of time/mileage by the feds. So the reality is that you may get a BETTER oil for preventing wear when you choose a "high mileage" oil then if you choose the one that is the latest and greatest spec for new cars. This lowering of allowed amounts of anti-wear additives is why you are seeing more and more of the new car oil's becoming semi-synthetic - they can't get them to have sufficient wear protection with just dino oil and meet all the other requirements for reduced additives, etc. I think you are safe with any of the Mobile One products. If you have a newer car and plan on keeping it for a long time don't use the "high mileage" oil if you wish to make your cat converter last as long as possible. On the other hand, if you really want to maximize anti wear protection and are willing to maybe have to replace the cat at some point, then the High Mileage oil may actually be the best choice.

They claim the new generation of seal conditioning additives are not softeners, as such, but are high mol weight polymers. Polymers of this type can have viscosifying effects in tight places without showing the macro effect of viscosifying the oil in general. (This effect is genuine in principle)

Again, anybody can make claims about anything.

AFAIK the best choice in that respect is a "fleet" oil like Rotella or Delo, but NOT the versions that meet the latest API specs. There's been a fairly lively discussion about this over on the Studebaker forums (as Studes, like many old cars, use flat tappet cams, so ZDDP content is a real concern.)

nate

Yeah, I've been hearing that too. There was a lot of talk about it in a classic T-bird group regarding what oil to use in the old FE big blocks in the old birds. Many suggested the Rotella and similar diesel oils or at the very least to stay away from the energy savings oils. I"ve been reading that one of the reasons most newer engines went to roller tappets was because the new oils simply can't provide enough high pressure anti wear to protect the cam/tappet interface on the non-roller designs.

Well, I've decided to field-test the "High Mileage" oil in my 160K+ miles Stratus, and I put it in. I'll consider it a success if it doesn't require a top-off for the 7500 miles I plan to keep it. If it does, I'll switch back to the "Extended Performance", which needs a quart every 2 to 3 thousand miles, but this at least adds some fresh anti-wear that helps it last the 15K.

Asht>