Switch From Single Grade Oil to a Multi-grade

G

graybeard47

Recruit
Joined
Feb 16, 2009
Messages
4
I have a 1985 350 Mercruiser IO that has extremely low hours on it and have been using a name brand single 40 weight oil that the owners manual stated to use for summer use. However, these higher single grade oils are pretty much disappearing. We have a large speed shop in our area that carries single grade racing oils but have seriously been considering switching to a multi-grade in light of the tremendous advancement in motor oils since 1985.

What short-comings am I looking at switching to 20-50 semi-synthetic/ full synthetic oil or should I leave well enough alone and stay with the 40 weight?

Thanks
 
H

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Switch From Single Grade Oil to a Multi-grade

Howdy,


Well, have a look at Mercruiser suggested oil.


faqs_temp.gif

NOTE: The use of non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W rated synthetic oils, low quality oils or oils that contain solid additives are specifically not recommended.




If you don't want to use what they suggest. You can literally use what ever you want. There's no evidence of marine engines failing due to oil type(or brand).

I use XXX oil and have never had any problems.....


Do a search on this forum or on any marine (or other) forum and you'll find that every type of oil has been used successfully.


Just change it once a year at the end of the season and you won't go wrong!


Cheers,


Rick
 
Ducatinut

Ducatinut

Seaman Apprentice
Joined
Apr 8, 2007
Messages
42
Re: Switch From Single Grade Oil to a Multi-grade

HT32BSX115 said:
If you don't want to use what they suggest. You can literally use what ever you want. There's no evidence of marine engines failing due to oil type(or brand).
Click to expand...

Oh, no... Now you've done it, Rick... :D

(I run whatever straight 30 weight that I catch on sale)

Fair winds,

Chris
 
Rocky_Road

Rocky_Road

Lieutenant Commander
Joined
Oct 8, 2008
Messages
1,798
Re: Switch From Single Grade Oil to a Multi-grade

Ducatinut said:
Oh, no... Now you've done it, Rick... :D

(I run whatever straight 30 weight that I catch on sale)

Fair winds,

Chris
Click to expand...

Actually, Rick has the single answer that should be mandatory on ALL of these oil posts.

If you aren't willing to trust the engineers that designed your engine, than I guess that you should go ahead and trust what anyone wants to post here.

And if your engine goes 'south', be sure not to slam the manufacturer....

Happy boating!
 
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