View Full Version : Oil viscosity ? 98 PS 205

01-06-2012, 09:45 PM
I have a dilemma about what viscosity to use. The manual I downloaded from the MC site says to use 20W50. The caps on the valve covers say 10W30, but one of them had a sticker showing 10W40, presumably from a previous oil change. I searched and read through quite a few threads, but couldn't find a conclusive answer. Is there any reason to not stick with what was in the manual?

01-06-2012, 10:20 PM
After reading a lot of threads here, I run 15w-40 on mine (conveniently placed right in the middle between your two options there). Delo or Rotella; they're designed for heavy use in Diesels, and work quite well in our hard-use marine engines.

I also use the long oil filter (Napa 1060 or equivalent) rather than the stock short filter (pennzoil PZ-3, equivalent to the Napa 1069). I think it has more filtering area, and there's no problem with clearance on my boat.


01-06-2012, 11:39 PM
I change oils at 50 hours or three thousand miles. Obviously on the boats it is by hour meter. I run 15w-40w synthetic in most of my boats and vehicles. I run 20w-50w synthetic in my Harley's. Seen the temperature drop in the motorcycles from synthetic. Decided that it would be good for everything. The one problem with synthetic is that if you have a seep or weep it will find it. Not a recommendation but just a statement on what I do with the choice of oils. Oil is cheap insurance to my way of thinking.

01-07-2012, 04:56 PM
Thanks for the replies. Bought 15W40 Rotella today. Spent the afternoon scrubbing the boat nice and clean. Tomorrow's agenda is change the oil, drain the engine, oil the seats, and as much waxing as I can get done before I have to call it a day. Then it'll go in the garage for a few months.