The last word on oil change intervals?

[abscate]

My use case has changed so much I just do one annual oil change on every car in the fleet

[erikv11]

Brining back an ancient thread. What interval is everyone doing now?

Me: P2 cars with 2.5T engines > 100K miles. These cars need 1 qt of oil added every 1,000 miles or so...

- Synthetic 5W40
- Mahle oil filter
- Every 7K miles or so...

So you routinely add 5-6 quarts between 7k oil changes? That sounds way out of range, the cars must have leaks?

Otherwise I'm doing exactly what you said, except that my P2 cars need a quart about every 3500 miles. I.e. top up one quart halfway through the OCI, then by the time it needs another quart it's time to change the oil. Works out well.

[kcodyjr]

So you routinely add 5-6 quarts between 7k oil changes? That sounds way out of range, the cars must have leaks?

I agree, at this rate the oil is always fresh, and you're just changing the filter.

Sounds like it has seal issues. Actually, sounds like it's leaking like a sieve.

[Cees Klumper]

We have two Volvos, 2001 C70 T5 and 2002 S80 T6, each with 150K plus miles, that we now drive only during Summers, less than 2K miles a year. I change the oil and filters once every two years, synthetic, store brand. They don't consume a drop of oil, engines are very strong and fuel consumption is very low. Oil still looks new after the two years.

[Krons]

Change intervals in my opinion varies by driving habits and oil quality. A vehicle run on short trips can create crankcase moisture and ultimately sludge if temperatures don’t get hot enough to burn that moisture off. Conventionals and Semi synthetics are also more prone to sludge. I personally would not trust the oil or filter any quick change shop uses.

I bought my kids 02 S60 with 150k miles and found significant sludge evidence, pretty sure it had 7500 intervals. With a few 2000 mile then 3000 mile intervals the engine has cleaned up, added a 1/2 qt of marvel mystery oil on the first few changes to help gently break the sludge down without clogging the pickup screen.

Similar with the 05 XC90 I bought at 190k miles, 7500 intervals and sludge evidence. Looked black like diesel oil in 3000 so changed it.

So, I go a lot off of oil color. If black at 3000 I’ll change it, if the vehicle had some long trips I may stretch to 5000. I don’t want sludge so never longer than 5000 for me–a quality oil and filter is $30-40 or less at Walmart.