Engine Life - how much do you gain

[Jim Miller]

I'm one of those change your oil every 3000 miles (before synthetic, 5,000 now) guys. How much engine life do you gain, 5000 vs 7500 vs 15000? Any statistics or opinons out there? Oil changes are not cheep especially when you need almost 10 qts of oil.

[pothole]

I thought there was some evidence that you could change the oil too frequently. Something to do with ingredients breaking down during initial use. Personally, I can't imagine there's much benefit from changing your oil more frequently than every 5-6,000 miles.

[stephen wilson]

IMO that's why oils are such a hotly debated subject, it's virtually impossible for the average user to quantify the gain in service life. Though I think the benefits of synthetic oils are well proven. I've run 2 cars on Mobil 1, one with oil changes @ <5K miles, and a beater @ 10K miles, both are running fine with 190K miles and the valve-trains look great. No internal engine problems. Extreme usage, or problematic engines may show different results.

[jcb986]

7,500K on oil change. Change the filter at 3500 then change oil and filter at 7,500.

[Jim Miller]

The ironic thing is rarely keep a car to the engine dies. I see people rebuilding engines with less than 100K is it the lack of oil change, defect or being run too hard?

[blue2000s]

I would love to see anyone, with any engine, show a correlation between oil change intervals and engine longevity. I have never seen such a study anywhere.

I believe any answers that you get to this question will be anecdotal at best.

[KevinH1990]

Originally Posted by blue2000s

I would love to see anyone, with any engine, show a correlation between oil change intervals and engine longevity. I have never seen such a study anywhere.

I believe any answers that you get to this question will be anecdotal at best.

I think Consumer Reports did a study several years ago. If I recall correctly they used New York City taxi cabs. They tested a range of oils and then tore down the engines after 50,000 miles and measured the wear. I'll see if I can find the article. Memory tells me that they didn't find any extraordinary differences between oils. Fuel economy was slightly better with synthetic oil, but not enough to justify the higher price.

Having read reports of engine failures on this and other Porsche boards, I don't recall any in which the owner says they neglected oil changes. Most seem to say that they changed the oil frequently.

[Brucelee]

Nobody knows, but most have an opinion.

[tuanle16]

Originally Posted by jcb986

7,500K on oil change. Change the filter at 3500 then change oil and filter at 7,500.

i was actually told by my mechanic the opposite. he said that you can change your oil every ___ but change your filter every other oil change.