I have never used it but it should flow like any 50w oil. Will probably take a little longer for the oil pressure to drop into the normal zone after a cold start. Your normal oil pressure can be a little higher too.
0W, 5W, 10W, 15W have defined viscosities at defined temps-so 15 W will not match these. The viscosity 0f a 0W oil at -30 C (3250 cP) is about the same as 15W oil at -15 C (3500cP). Now if you are talking a 10W-30 oil (conventional) then there isn't a lot of difference and probably at about -30C (-22F) there won't be a lot of difference between the 10W-30 Conventional and 15W synthetic. But they are both pretty much useless there-or close to it.
If you are talking a straight 30 wt. then the 15W-50 will be waaaaaaaaaay thinner at lower temps.
[ June 17, 2003, 08:26 AM: Message edited by: Al ]
To answer your question without going off on a diatribe....how well does it flow? Well, Mobil tech line once said "the 15-50 is about TWICE as thick as the 10-30". Having used it...I'd agree. So if you're familiar with 10-30, then double that...and you should get an idea of how it "flows"...