The older the car gets - more oil changes?

Not open for further replies.
Mar 27, 2003
Toronto, Ontario
I was wondering if the older a car gets the shorter the duration between oil changes should be? I am talking about cars with over 100K. Does this make sense? My logic is as the cars gets older it will polute the oil more and will need to be refreshed more often. It would also help to clean out the sludge I am guessing.
I have noticed that when a car is fairly new , the oil does stay (visibly) cleaner longer than the same car with lots miles on it so it would seem logical to assume that the oil has to deal with more contamination with an older engine.
Changing the oil at intervals less than 3000 miles or every 3 months (which ever happens 1st) is still probably overkill and wasteful in any case.
If the engine is still clean inside, it doesn't need more frequent changes. An older car that has been neglected will degrade it's oil faster, but an older car in good shape can still do long intervals. Check out our UOA section here for proof.
I'd recommend doing an oil analysis spot check every 50k miles, to see if the oil is in fact degrading more quickly. One thing to keep in mind is that high mileage engines burn more oil, so you are adding fresh oil between changes. This helps to dilute any contaminents and replenish the additive chemistry ....

First you'd have to decide what an older car is.

If the engine is a more modern design, I wouldn't even consider it to be aging until at least 150k, maybe more. 100k is gravy for modern engines. So I wouldn't change a thing at that point, and probably never unless there was an obvious symptom.

Cheers, 3MP
Based upon my experience with my 92 Camry (154,000 miles)where I have done oil analysis at least every year I say NO. The wear metals and silicon etc. actually decrease for the first 30,000 miles or so and then basically level out. I have seen no dramatic increase in anything over the years to indicare more frequent changes are necessay. The only issue for me now is that I am putting on fewer miles and this extends what used to be 6 months for a 7500 mile drain to 9-10 months which may have an impact on the analysis. So far it has not but will see.

Driving conditions more then age I believe are more important for change frequency

[ April 03, 2003, 09:25 AM: Message edited by: Spector ]
Getting wear to slow to an absolute minimum ought to be the goal. Keep to factory schedule, keep ignition like-new.

I converted a 1977 Impala wagon in 1986 to M1 at 112,000 miles, drove it to over 240,000 with a near-dead cylinder. Passed emissions easily and oil consumption stabilized for the entire time I had the car. Maintenance was not skimped, but heads never came off (didn't want to do ring job on an inferior Chevy V8). Oil change frequency was not increased.
Not open for further replies.