Volvo 75w 90 synthetic gear lube in a 1989 Cobra drive.

[Donzi GT250]

Any reason not to use Volvo Penta 75w 90 synthetic gear lube in my 1989 5.7 Cobra drive (other than price)?
Also is Evinrude HPF Pro a full synthetic lube and what weight is it?

Thanks

 

[Bridar]

Re: Volvo 75w 90 synthetic gear lube in a 1989 Cobra drive.

Other than price? No. In fact, I use 75W90 synthetic in my sterndrives, my outboard, my ATV diff's and the chaincases of my snowmobiles.

Evinrude HPF Pro is BRP's premium synthetic oil with a number of additives that they claim make it "the perfect oil for use a marine environment". BRP (like most manufacturers) is famous for marketing all their oils as "Premium High Performance oil" for their vast variety of powersports products. What they don't tell you is the grade, and that you can run a generic equivalent for a fraction of the cost that will work just fine. For example I can buy a liter of 75W90 synthetic at Canadian Tire for $11, while a 355 ml bottle of Bombardier's synthetic chaincase oil (actually 75W90 synthetic) runs between $30 and $40. You do the math.

 

[Donzi GT250]

Re: Volvo 75w 90 synthetic gear lube in a 1989 Cobra drive.

Nowhere on the HPF Pro bottle does it give the grade (weight) of the lube.
Also it doesn't say it is full synthetic either.
It does say it has synthetic additives.
So I guess the question still stands.
Is HPF Pro a full synthetic and what is the viscosity grade?

 

[Bridar]

Re: Volvo 75w 90 synthetic gear lube in a 1989 Cobra drive.

That's just it... the manufacturer invests a lot of money in the development of their product so they aren't about to advertise the grade, the ingredients or much about their blend of enhanced friction reducers, anti-foam agents, and synthetic E-P additives, etc. It makes it hard to judge whether one should spend 4 or 5 times the price for an oil that may only be 5% better than a generic synthetic.

Generally speaking, oil manufacturers normally label their synthetic gear oil as 75W90 where it serves as a replacement for conventional 80W90 gear oil. In the case of a performance oil produced specifically for lower marine gearcases, the grade & weight is really incidental.

More to the point, I think it's more important how often you check and change your oil than whether you should pay top dollar for the 'top shelf' oil. Is HPF Pro a better oil than cheaper synthetic or conventional? I believe it is, but if you have water infiltration in your gearcase and you don't check it, it will still eventually fail.