"High Mileage" oil; experience, knowledge of?
 

So thinking of switching from plane jane dino oil to high mileage dino oil in my '92 which has 220,000 miles (overall excellent condition).
Purpose would be to prolong oil tightness of seals.

This high mileage oil is sold (by several oil firms) in all auto parts stores and claims to promote seal tightness/integrity.

But, I've no background with this type of oil. Does anyone have personal experience to draw from, or knowledge of ...

Thanks

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In oil types, there's synthetic, semi-synthetic, dino/regular, and this High-Mileage type.

I'm looking for experience with / knowledge of this High-Mileage type oil.
Most of the oil companies sell it. Common enough.

Anybody help? Any experience?

I don't have any experience, but I'll chime in cause nobody else did. I haven't used that kind of oil, even owning cars up to 220k miles. My opinion is only use them if there's an actual reason. Burning oil because of rings blowby? Low oil pressure from worn bearings? Leaking oil from old hardened seals? Anything specific like that?

I wouldn't use it JUST BECAUSE a car has "high mileage". I'd want to have an actual reason.

I am with Jim on this. If it aint broke, don't fix it. The more important thing is to change the oil at the recommended intervals and check the oil level.

235k on my son's '96 Accord EX ... when we got the car (at 228k) it was leaving a few to several drops of oil at each stop. I replaced distributor and VTEC seals, PCV valve and some hoses, which helped a lot, but still had seepage from the rear main seal and what seemed like a bit from the front seals, even though those had been replaced at 150k by the previous owner.

Aside from replacing what seals I could, I switched to Castrol GTX High Mileage and have been keeping to 3k oil change intervals to try to remove the crap that was built up inside the engine by cheap oil and overdue oil change intervals from the previous owners. A week or two before each oil change I drop in some Barr's Rear Main Seal Leak Stop to let it work on the rubber for a bit (but not too much as I've heard it can be harmful if left for too long).

So far so good. The bottom of the tranny is still wet, but no dripping anymore that I can see. I'm sure it still drips a bit when at speed, but the amount of oil loss from driving is decreasing steadily.

We are also keeping to good quality gas (Shell, Chevron, 76) to try to keep the fuel system as clean as possible. I am also going to introduce a bottle of Techron additive once or twice a year. These engines have EGR port clogging issues ... don't know if consistent use of good gas is going to help. But so far the engine sounds very smooth and solid and we have seen no CEL misfiring issues in the past 18 months that we have owned the car.

I'm still not sure if VTEC is engaging ... that's next on the list ...

I strongly agree with the comments above, use it only if there's a reason to. Of course the manufactures advertise to use high mileage if your car has over 75,000 miles on it, but don't let that fool you. High mileage oil has added seal swell additives that do work but there's only so much you can do for worn seals, after a while they can't expand anymore and then you have no other choice but to replace them or face major leaks. Of course there's no such thing has a mechanic in a bottle, if you have leaking seals and want the problem to go away, just replace the seals.

My 2000 accord has only has 74k miles on it so I have no experience with high mileage oil on it, but I also have a Dodge Stratus with well over 260,000 miles on it and it has been leaking drops of oil from many different seals and gaskets since they were never replaced once. After switching to Mobil Super high mileage oil, the leaks did indeed slowly reduce to the point where the amount of leakage wasn't anything to be concerned about. As for how long before the seals start leaking again, I can't say, but before switching oils it was using a little over a quart of oil every oil change at 5,000 miles, between burning it and leaking it, now I'm down to maybe missing not even 1/4 a quart of oil between oil changes.

Hope that helps shed some light on high mileage oil.

Jkowtko is an example of having an actual reason to use high-mileage oil. The additives help swell his main seals and postpone replacing them. It's kind of a cost-benefit thing. High-mileage oil costs more, so it makes sense if you can postpone or eliminate a high-$$ repair. But I wouldn't use it on an engine that doesn't leak, doesn't have any other issues, and simply has high miles.