View Full Version : Motor Oil

12-20-2004, 10:21 AM
I am getting ready to perform my first oil change on my boat, a '91 PS190. I've heard that marine 15W-40 is the oil to use, however all that I can find is some no name brand of 15W-40 at Boater's World. I'm wondering if I am better off using that or using a "known" brand of regular motor oil, or even switching to synthetic oil since it is a bit older engine and I'd like to keep it running as good as it does now for as long as possible. Any thoughts or experiences?

east tx skier
12-20-2004, 10:30 AM
Walmart should have Penzoil Marine 15W40 in its boating section (not with the automotive motor oils).

12-20-2004, 10:36 AM
Cool, I'll take a look. Do you recommend synthetic at all, or I am I better off staying with regular? The engine has 724 hours on it, and runs smooth and quiet. I tend to be a bit anal when it comes to maintenance on any of my vehicles which I why I ask.

east tx skier
12-20-2004, 10:48 AM
I don't have a preference. I just run what Indmar says. As you can see, the selection for the 15W40 marine wasn't very large. I looked at Wally World's Auto Oil section for ever before cluing in on the marine section. Who knew?

12-20-2004, 10:57 AM
No need to go synthetic if you do your regular 50 hours oil change...My .02 cents

12-20-2004, 11:02 AM
good info, thanks!

12-20-2004, 11:29 AM
Ditto on the synthetic, unless you put alot of hrs on it, but you said you're "anal" about maint anyway, so dino oil would be fine, changed regularly. 15w-40 is a reccomendation only. In the past, when oils were straight viscosity (SAE 30w, etc), the viscosity was more of a consideration due to ambient and operating temperatures.
A 15w-40 oil is designed to have a low temp viscosity of a 15W oil, w/ a high temp viscosity / thermal breakdown resistance of a 40W oil. Actual viscosity of the oil at a given temp may or may not be the same as the old oils. That said, you're safe to run 10W-40, 10W-30, 15W-50. As long as the viscosity range is similar to what's reccomended. Any good quality automotive oil will be fine.
Engine wear is much more attributable to operating conditions (overheating), and timeliness of oil changes than to exactly what brand or weight you're running.

Zach S
12-20-2004, 12:20 PM
I have been using Rotella T 15W-40. I think last time I bought it, it was labeled for trucks. :twocents:

east tx skier
12-20-2004, 12:30 PM
From what I've seen, 15W40 is common in Diesel applications.