Synthetic or mineral oil in an OMC 4.3GL 1995?

[ach1982]

Hello,
I'm new in this forum.
I'm a owner of a 1995 Four Winns Horizon 192CB with an OMC Cobra 4.3GL.
I bought it with a fresh service, but now I have to prepare the witerization. Its the first time for me with this engine.
So my question is, which type of oil I have to fill in?

Please don't say...not another oil question again? :facepalm:

It's a little bit confusing. The OMC manual says, that I have to fill in a SAE30. But the manual is from 1995 and I'm convinced, that there are better oils out now.
Then I looked up the recommendation of Volvo Penta for their 4.3GL. They recommend a 20W50 oil.

It is nowhere mentioned, if I have to use mineral or synthetic oils.

I asked two workshops.One recommended a synth and the other one a mineral. It's a really confusing topic.


Please give me a hint, a recommendation or tell me your experience about the oils in my engine.
That would be great.

 

[Scott Danforth]

first, welcome aboard

oil has been beaten to death in the forums (simply do a search)

in your 95 OMG
doesnt matter if you run squished dino oil or synthetic or synthetic blend.....single vis or multi vis.....
you still need to change it at end of season whether you have 1 hour on it or 50 hours on it (the whole byproduct of combustion being detrimental issue)

your motor has a roller cam vs a flat tappet cam, so make sure you understand oil needs vs the ratings.

flat tappet cams like zinc, roller cams dont necessarily need zinc (depends on the motor) I personally run Rotella T 15w40 (still has zinc) in nearly everything. the boat, the lawn mowers, 3 of the 4 cars. the VW gets synthetic 0W-40. A gallon of 15W40 is $12 a gallon of 0W40 is $22.

OMC manuals wont say run synthetic for a variety of reasons. number one being OMC went out of business prior to synthetic oils going mainstream

so buy oil and filter, do your maintenance and go boating.

 

[ach1982]

first, welcome aboard

oil has been beaten to death in the forums (simply do a search)

in your 95 OMG
doesnt matter if you run squished dino oil or synthetic or synthetic blend.....single vis or multi vis.....
you still need to change it at end of season whether you have 1 hour on it or 50 hours on it (the whole byproduct of combustion being detrimental issue)

your motor has a roller cam vs a flat tappet cam, so make sure you understand oil needs vs the ratings.

flat tappet cams like zinc, roller cams dont necessarily need zinc (depends on the motor) I personally run Rotella T 15w40 (still has zinc) in nearly everything. the boat, the lawn mowers, 3 of the 4 cars. the VW gets synthetic 0W-40. A gallon of 15W40 is $12 a gallon of 0W40 is $22.

OMC manuals wont say run synthetic for a variety of reasons. number one being OMC went out of business prior to synthetic oils going mainstream

so buy oil and filter, do your maintenance and go boating.

Thanks a lot for your information.
I live in germany and boating is not really widespreaded. So here you have a few workshops and a few part-delers around, but everybody tells you different.
And... we're not really used to the old "big" US engines. But I can tell you alot about your VW engines (be careful if it's a TSI with timing chain!!!).

 

[Scott Danforth]

dont worry, I can probably tell you a few things about most of the cars in europe as well as the US and some korean and japanese

the 4.3 isnt really big by any means. the 7.4 liter im building into an 8.1 liter is big..... especially when you drop an 80# cylinder head on your leg

 

[Lou C]

What you have is probably an OMC Cobra that was built during the joint venture era with Volvo ; as such it is identical to a Volvo SX system of the same year.
For engine oil of what's commonly available I like the Mercruiser 25/40 conventional marine oil or the Sierra equivalent . For out drive oil I use the Mercruiser High Performance gear lube. Both are widely available here in the US. There is another guy from Germany who's user name on thehulltruth . com is Divefreak. He seems to work in the marine tow business and may be a good resource for you.