Higher Grade with Higher Miles

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Any evidence to support higher grade with higher miles?

Lots of guys down south with 400,000+ mile pickups that did the 5W30 PCMO to 150,000 / 10W30 HDEO to 300,000 / 15W40 HDEO at 300,000+ type deal. Any evidence this is actually beneficial?
 
I'm not sure how we would gather "evidence", per se, but there are plenty of anecdotes about "looser tolerances" on older trucks.
 
I'd move up a grade with higher miles if I started to use oil, otherwise I'd leave it alone.
 
Originally Posted By: Gene K
Any evidence to support higher grade with higher miles?

Lots of guys down south with 400,000+ mile pickups that did the 5W30 PCMO to 150,000 / 10W30 HDEO to 300,000 / 15W40 HDEO at 300,000+ type deal. Any evidence this is actually beneficial?



That sort of run-up has always worked for me. But I don't have any cars or light trucks that have recently made it over 287,000 miles. Not because they were not running fine (they were), but at that point they would no longer pass Calif SMOG testing w/o a new cat and the vehicles were not worth it ...

The '62 Ford F-100 went 400K plus doing that sort of oil up-grade. But that was many years ago ...
 
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Define "Higher Mileage"
100,000 miles is just broken in.
200,000 miles is starting to sound like "higher mileage"
300,000 mileage run what suits your fancy, you got your money and then some out of her.
 
Plain bearings with abrasion scratches over times,even if bearing clearances hasn't enlarged, would require higher operating viscosity at similar conditions of engine rpm and load than an original bearings.........
just to maintain similar MOFT, and by extension film strength.
blush.gif


It makes sense to up a grade or two for used bearings ..... and used interfaces at cylinder liners and cams.

Edit:spelling
 
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I had a old Volvo with 289k miles had bad compression but refused to die. Pretty much everything that could break on this car had by the time two of my son's had it as there first car.

It leaked and rattled decided one day to try 10w50 (or 15w50 been several years back) anyways the car became dead silent. You could stand by the hood and wouldn't know if it was running after the thicker oil was added.

But I also had a '01 Chevy 1500 with 360k miles and it ran perfectly fine till the day it blew the head gasket. Used 10w30 and 7,500 mile OCI it's whole life.

I guess it would really just depend on the vehicle.
 
Originally Posted By: zeng
Plain bearings with abrasion scratches over times,even if bearing clearances hasn't enlarged, would require higher operating viscosity at similar conditions of engine rpm and load than an original bearings.........
just to maintain similar MOFT, and by extension film strength.
blush.gif


It makes sense to up a grade or two for used bearings ..... and used interfaces at cylinder liners and cams.


CORRECT!

One easy way to figure out if the engine is worn is to keep track of the oil consumption figures. In general terms I would only move up one grade from OEM spec, BUT I would find out what that spec was for use outside the USA, as the one quoted from a US site might be biased by fuel economy regulations.

It also helps with an old worn engine to use an oil with more anti wear additives and detergents, although I would only switch to an HM oil when the oil consumption increases.

It's also very important to select an OCI that matches the condition and use of the engine, as older engines tend to contaminate their oil more. The best way to figure out what the OCI should be for an older engine, is to get a used oil analysis (UOA) done.
 
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