3K Vs 5K Vs 7.5K oil changes?

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All things being equal, lets say by 150,000 miles would there be a measurable difference in engine wear (or "life remaining") on a car that had OCI at 3K, compared to the same car with 5K and compared to the same car with 7.5K OCI?

As mentioned, all things being equal, and a high quality fully synthetic oil being used.
 
I think at those OCI's, the oil itself won't prevent any extra wear at all with normal usage. Only if you have some truly severe service where you're getting lots of gas in the oil, or follow road trains on dirt roads all the time, or have to run the engine WO at redline all the time? Then you might consider a shorter interval than 7.5k on good synthetic.
 
Impossible to say for certain. That being said, there are very few cars that can't handle a 5k or 7.5k interval with a modern oil.
 
UOA, testing, and what few experts still visit this declining site have told us that it is more beneficial to run the oil (whatever it may be) close or at the oil's limitation.
 
Originally Posted By: Oil Changer
this declining site


This place isn't declining....there are just more of "you guys" on here.
 
It probably depends on how you define "measurable". "Enough to make a difference" in terms of actual performance? I doubt there's a difference, at least 150K. Full tear downs in a theoretical world there 3 identical engines go thought the exact same usage over 150K? My money would be on the longer OCI's having the least wear. That's what pretty much every bit of public research suggests.
 
I think you are pretty safe to keep engine wear at a minimum with syn oil and a 5000 OCI based on my used oil analysis with 4 different engines used in severe service for 100-200k each. At 170-200k none consumed more than 1/3 quart of oil in 5000 miles and UOA showed very low wear metals below universal averages. So, that is my mantra now. 5000 miles with any synthetic and a factory or Fram TG or better filter.
 
In that lifespan of 150,000 no measurable difference to the owner and will continue that till 300k if owner changes oil with anything that is propr spec and interval for driving conditions.

My experience and parents is use whatever oil per car maker spec the engine outlives the car in New England.
 
Originally Posted By: Spetz
All things being equal, lets say by 150,000 miles would there be a measurable difference in engine wear (or "life remaining") on a car that had OCI at 3K, compared to the same car with 5K and compared to the same car with 7.5K OCI?

As mentioned, all things being equal, and a high quality fully synthetic oil being used.


your question is too generic.

If its a honda civic.. I'd probably agree.

most newer DI cars or DI TURBO cars.... would not agree.

What kind of service does it see?

My car with its 1 mile commute had putrid black oil that drained out with orange/brown foam on top at 2900 miles(4.5Months)
It was syn oil.

I probably should have changed it sooner.
Even though it did get driven on extended 30+ mile drives weekly or twice weekly.

Same car driven 20miles each way to work.. probably would be fine for 7500miles or more.


Edit:
by agree I mean no measurable difference
by disagree I mean it does need shorter oil changes
 
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I think it would make a difference in the many turbo diesel cars used mostly round town.

Lots of repeated acceleration then back to idle along with periods of extended idling are all hard on the oil.

Most Emergency Service vehicles in urban environments have relatively short oci.

In my previous workplace it was 3k or 6weeks.

This is even more relevant with the introduction of diesel particulate filters and the resultant fuel contamination
 
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