oil life
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oil life
In the md 1980s, when gm was selling lots of their crappy diesels, Popular mechanics did a test on engne oil life.
They basically took several cars and ran them normally with oil anaysis every 500 miles. They ran this test up over 12,000 miles on same oil and their results were interestingly that there was very little deterioration of the crank case oil even over this extended period. they actually terminated the test at 12000miles with the oils performing normally.
The only oil failures were in diesel cars, it was uncanny, when the manufacturer said to change their diesel crankcase oil at 3000 miles, it was found that very near that point, the oil changed into some new and exciting chemical probably through contamination and blowby which is a diesel problem.
I have always changed my gasburner oil at around 6 or 7k with excellent results in working commercial trucks.
I suppose I took this test seriously, but it has always'worked for me. In fairness, I think the arizona climate is easy on oil. If I lived in a colder climate, I would change much more often.
Ken
They basically took several cars and ran them normally with oil anaysis every 500 miles. They ran this test up over 12,000 miles on same oil and their results were interestingly that there was very little deterioration of the crank case oil even over this extended period. they actually terminated the test at 12000miles with the oils performing normally.
The only oil failures were in diesel cars, it was uncanny, when the manufacturer said to change their diesel crankcase oil at 3000 miles, it was found that very near that point, the oil changed into some new and exciting chemical probably through contamination and blowby which is a diesel problem.
I have always changed my gasburner oil at around 6 or 7k with excellent results in working commercial trucks.
I suppose I took this test seriously, but it has always'worked for me. In fairness, I think the arizona climate is easy on oil. If I lived in a colder climate, I would change much more often.
Ken
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I always thought it odd our '87 Toyota MR2 owner's manual called for 10,000 mile intervals while our newer Fords were more frequent.
A long time buddy changes his oil once a year in his "79 Subaru and has been driving it 15-20K annually since it was new and has never had to touch the engine.
A few years ago, one of the oil companies ran afoul of the FCC (or FTC) for misleading television advertisements. White smocked "engineers" drained the oil from two "identical" engines and ran them until one engine siezed and with a few orchestrated, special effects, died a horrible, smoking death while the engine with the advertised oil continued to run. Competitors cried foul and the FCC (FTC) looked into this and ran their own tests. Surprise, the advertised oil did not perform any better than the other brands. What was truly incredible was that all these drained engines ran for something like 36 hours on average before finally siezing up. (I wish I could find the link to this article but I recently suffered a hard disk failure and lost all my reference material.)
A long time buddy changes his oil once a year in his "79 Subaru and has been driving it 15-20K annually since it was new and has never had to touch the engine.
A few years ago, one of the oil companies ran afoul of the FCC (or FTC) for misleading television advertisements. White smocked "engineers" drained the oil from two "identical" engines and ran them until one engine siezed and with a few orchestrated, special effects, died a horrible, smoking death while the engine with the advertised oil continued to run. Competitors cried foul and the FCC (FTC) looked into this and ran their own tests. Surprise, the advertised oil did not perform any better than the other brands. What was truly incredible was that all these drained engines ran for something like 36 hours on average before finally siezing up. (I wish I could find the link to this article but I recently suffered a hard disk failure and lost all my reference material.)
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Joined: Apr 2005
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From: Washington state
the newer commercial diesel engines with electronic engine control routinely get 15k to 20k miles per oil change due mainly to much reduced fuel dilution of the oil which causes oil breakdown, new lower sulfur higher quality diesel fuels help also.
rarely see one of the modern over the hwy big rig diesels smoke now even on a hard long hill climb.
remember my first trip to state required emissions testing.
long lines, old GM product station wagon with that abortion 350 GMC diesel converted car engine pulled in with stuffed full of small noisy wild kids, woman had her hands full, more diesel coming out the exhaust pipe than producing power in the engine, she turned it off and then restarted several times, black smoke cloud would block the view into the testing station, everyone in the lot was coughing, her turn finally came, tech stuck the test pipes in her exhaust, ran it on the dyno, smoke billowed out, engine coughed and bucked
she passed!
pulled back out on the road with that load of kids and floored it, looked like the pocket battleship Bismarck on a smoke run.
rarely see one of the modern over the hwy big rig diesels smoke now even on a hard long hill climb.
remember my first trip to state required emissions testing.
long lines, old GM product station wagon with that abortion 350 GMC diesel converted car engine pulled in with stuffed full of small noisy wild kids, woman had her hands full, more diesel coming out the exhaust pipe than producing power in the engine, she turned it off and then restarted several times, black smoke cloud would block the view into the testing station, everyone in the lot was coughing, her turn finally came, tech stuck the test pipes in her exhaust, ran it on the dyno, smoke billowed out, engine coughed and bucked
she passed!
pulled back out on the road with that load of kids and floored it, looked like the pocket battleship Bismarck on a smoke run.
Last edited by 96_4wdr; Oct 14, 2005 at 07:09 PM.
