O.K., this is great! thanks Road Rage for the great report. I've read most all the repsonses
and found numerous other studies on the Web. Here is the bottom line for me: I love this
car and expect to keep it forever, I'm 58 years old so that may not be too long! i want to
take the best possible care of the engine. I will change oil every 3,000 miles no matter
what the manufacturer says you "can do". In one report I read it said changing the oil
every 3,000 with a synthetic oil might actually be "harder on an engine" than letting it
"age"?! Come again, is that really true? If I use Mobil One and change every 3,000 miles
could I actually hurt it?

TechRep
(I'm the Nikon Techinical Representative for Nikon Camera company in the
Southern U.S.)

And I can't type or spell Technical!

Will not hurt it but why not use a dino oil if you're changing that often?

Actually, you can over change it, and that is not restricted to synoils - it is a little known issue hwoever, and worth looking at with a scientist's eye (not a Jiffy Lube or Uncle Ed's anecdotes).

The additives in an quart of oil are suspended in a carrier oil, which consists of light faction oils, usually paraffins. These carrier oils are very volatile, so they are inclined to burn or boil off early in the oil's lifecycle. Some of the chemistry in the add pack, like phosphorous, will therefore, get into the oil, and can harm the catalytic converter over time. This is why the API-SL spec reduced the amounts of ZDP allowed - to benefit the mfr's who have to cover the cat for at least 70k, and longer in California. So they made the companies reduce the most effective anti-wear compounds known to lubrication science to benefit:
1) you? Nope. 2) Themselves? Right!!!!!

Get it?

Some mfr's chose not to reduce the protection of their oils - LE is one of them - 8130 is SH-rated. But since it can easily go 7500 miles between changes, by your oil change interval, that would be over twice as much SL-oil, and the likelihood is high that you would be actually dumping more of the cat-harming material into the cat than the LE oil. Now, it may be that the SL oils have adequate additive chemistry to protect for 100k, 150k, or more. But I think there simply is not enough experience yet to know for sure - certainly, race oils have not dropped the ZDP levels one part per million!

I agree that if you insist in changing every 3K, use a good minoil like Motorcraft's. But you really are wasting you money, and the world's resources.

Honda has gone away from any pre-set OCI in the TL, Ford has settled on 5K even for severe service, and GM is going to have oil life programs in all its cars soon. The 3K oil change is a relic, and it seems to be hard for some people to shake, but based on your background, you should be able to understand the science of it, and get over it.

I do 3K oil changes - am I a hypocrite? No, that represents 1 year of driving for me, and the acidification that might occur from the US' high sulfur fuel puts my engine at risk, even though LE and Delvac (my choices, see my sig) are highly acid buffered, with hight TBN's.

Just when you thought you knew enough about oil, RR comes up with yet more interesting information. Thanks!

hypocrite? no. but in an automotive sense, you're practically celibate!



go forth and drink DEEPLY from the well of VTEC...

You imply that the oil companies are the bad guys here and that is not true. They formulate oil with guidance as well as pressure from both the auto manufacturers and the environmental agencies.

The auto manufacturers are forced to produce pollution gear that has a longer life so they specify formulations that contain fewer compounds that foul the cats and sensors. The oil companies respond to stay in the marketplace, trying to substitute additives to maintain performance.

Sure the oil companies can all do as LE and stick with SH spec formulations.. but the auto manufacturers are specifying that SJ, and SL oils are required for new cars. So this is a marketplace decision, not an anti-consumer move.

It is a safe bet that this makes little to no difference for most consumers.