Volvo Penta recommendations - confusing

[medic]

Quote from the current manual:

"To obtain the best engine performance and engine life, Volvo Penta recommends synthetic engine oil labelled for API Service CF/SH and ILSAC GF-4"

I'm a bit confused. Doesn't the GF-4 go hand and hand with API SM?

Anyway, the whole reason I am looking into this in the first place is because I wanted to run GC in my Volvo Penta 3.0 GL. GC is only labelled for ILSAC GF-3.

I was a bit surprised to see this recommendation for synthetic, but then I felt better as Volvo Penta stuck to the old school marine ways with this statement:

"All models are required to use a mineral-based oil for the first 150 hours. After 150 hours, the operator may continue to use mineral oil or switch to synthetic oil."

I haven't' been here in a while, but the last I knew, GC didn't contain any VI's and handled fuel dilution well. I did a search and couldn't find where anyone had mentioned GC in the boat lubrication forums.

 

[PT1]

I would never use GC in a marine engine. Not a stong enough additive package and won't protect against fuel dilution and corrosion during storage as well as a marine 40w oil or HDEO 30w or 40w. You would be wasting money and using the wrong oil.

 

[lars11]

Well my manual for the 5.0Gi 1999 says:
- 15w50 API SH or better Mineral oil
OR
- SAE 30 Full Synthetic

Newer 5.0GXi engine manuals states 15w50 Full Synthetic or 30 Full Synthetic.

I will be running Mobil Delvac MX 15w40 next season since I think that will capture average season viscosity reqs and have higher service ratings than the Volvo OEM oil.