Mobil One Synthetic

[Viper]

Ya I wouldn't paint all boat engines with the same brush, especially recent builds. If they call for synthetic, that's what you should be using. You can use synthetic on older engines but they do just fine with a good quality dino oil at regular maintenance intervals.

[Serendipity]

Thank you Tom for the heads up on your 1998 engines

[denpooch]

If you check the owners manual, the manufcturer will give you the proper oil specs.
My 2005 - 6.0 Crusaders recommend 'not' using synthetic oil.
I use 15W40.

[tomschauer]

From Crusader Owners Manual

Synthetic Oils
Synthetic engine oils may be used in Crusader Marine
Engines. Synthetic oils must meet the Engine Oil
Requirements for Classifi cation and Viscosity listed
below. The use of synthetic oil does not permit the
extension of oil change intervals.

[Viper]

Source of the post If you check the owners manual, the manufcturer will give you the proper oil specs.
My 2005 - 6.0 Crusaders recommend 'not' using synthetic oil.
I use 15W40.

That may have been so at the time of manufacture (2005), but formulations have changed, and so has OEM mindsets. I suspect if you check now, that wording would be different.

[Midnightsun]

That may have been so at the time of manufacture (2005), but formulations have changed, and so has OEM mindsets. I suspect if you check now, that wording would be different.

Agreed. Found it funny that Mercruiser was quite clear on NOT using synthetic oil in their engines way back. Oddly enough when Mercruiser started selling their own branded Synthetic oil they changed their minds and recommended it.

[bud37]

The advice has always been , when there is any doubt the best course of action is to consult your engine manual and follow the oil recommendations you find there......if that is done all should be well ....at the time the manual was printed they would have made their recommendations based on the engine build ( bearing and ring clearances, seals ) at that time period and if that is the engine you have then......

Of course there are many opinions as to what to do, I have my own...I have used one or another 15w40 for years with absolutely no adverse effects, since they stopped the green Kendall.... .....

The thread started with , should I start using synthetic oil now.......

[SunsetSteve]

Manual specifies SAE 40 over 50F (1983 Crusader). That is not readily available today. So we reach out, as here.

[tomschauer]

[km1125]

Source of the post <snip the video>

I like that guy's videos. He does a pretty good job capturing the gist of the topic at hand. I am a big proponent of synthetic oils for a lot of reasons. I used to run a lot of turbochargers on engines and what they do to conventional oil is brutal. I also remember one time on a VERY cold winter day up north where my car was the ONLY one in the parking lot to start, and I was the only one with synthetic in the crankcase. I've also torn down engines after over a hundred thousand miles of heavy-duty use and found impressively little wear on bearings and cylinders after living in a synthetic bath.

However, synthetic is much more expensive than conventional oil and there are a lot of engine applications that could never take advantage of all the benefits. Obviously you wouldn't be starting your boat engines in -20F temperatures but the heavy-duty usage could justify it.

I used to work for a "very old school" mechanic who didn't even like multi-viscosity oils. I still remember one of his favorite quotes on the subject:

"The only thing I know that gets thicker when it gets warmer is puddin'. And I ain't putting puddin' in my engine!!"