synthetic oil

[REDSC400]

Bruce,
You make an interesting point. On my daily driver, which I really take care of (1992 Lexus SC400), I change the oil and filter every 3000 miles which is about every other month. I run normal high grade Pennzoil 5W-30 in it, not synthetic. My typical drive is highway speed for about 45 miles one way.

The time intervals between my oil changes are short and the added expense of the synthetic is not worth it. The SC now has 120K miles on it and runs perfectly.

As I understand it, the synthetic oils and syn-blended oils have a few attributes which make them advantageous to use for some applications...

1) Light weight allows a nice film of oil to get between metal parts, resulting in more lubricity without loss of Horsepower.

2) Coupled with one above, superior high temperature viscosicty, the 5w-30 will stay 5w even at the high range of its intended use

3) Longevity - the synthetics are not supposed to break down as fast so their added expense is mitigated by longer oil change intervals.

4) Ability to provide lubricity when cold, especially good for what is known as "extream condition" driving, short one or two mile runs.

The reason I use pure synths in my Cobra is predominantly items 1, 2 and 4. I change out the oil twice a year. It comes out clear usually.

Cheers