What oil?

ric · **Posted:** Sat Oct 19, 2013 10:48 pm

The oil doesn't care what the engine is bolted into. The only reason multi-viscosity oil exists is so before it comes up to working temperature it's not too thick (killing economy and possible engine damage in really cold environments). The new 0w30 oils are so your car still gets 40mpg until the oil comes up to temp, which does take a while. Might get better economy with 10w30 in a raw water cooled sterndrive.

deafwish · **Posted:** Sun Oct 20, 2013 6:10 am

You bolt oil in to your engine?

You're doing it wrong, Ric! :lol:

How thin do you think your 10w30 oil is, once sheared & contaminated with fuel, towards the end of its service life?

ric · **Posted:** Sun Oct 20, 2013 8:18 am

deafwish wrote:

You bolt oil in to your engine?

You're doing it wrong, Ric! :lol:

How thin do you think your 10w30 oil is, once sheared & contaminated with fuel, towards the end of its service life?

I have yet to see any engine in the last 20+ years have a failure due to oil weight being too thin. I have seen failures when people DON'T change their oil (for years) or forget to put some in. If you change your boat oil every 20-30 hours like you're supposed to it doesn't matter what you put in there. Nobody in history of history has ever been like "Dang, I blew my engine running 10w30, wish I used 15w50 this wouldn't have happened!!"

Multi-viscosity oil was designed for two reasons. One: Extreme low temperatures where at -20 degrees you need a 0 or 5 weight oil at startup to avoid bearing damage. Two: Thinner the oil, better fuel economy you get. You would never run a straight 30 or 50 weight oil in an engine that sees temps below freezing or in something you're trying to get 40mpg out of. Such oils are designed for running at high temps in extreme environments. 15w50 is almost overkill in a marine engine due to our low engine temps, it might be okay here in Florida on a 100 degree day with 90 degree water but if you live in Michigan? You're just wasting power.

deafwish · **Posted:** Sun Oct 20, 2013 3:37 pm

ric wrote:

I have yet to see any engine in the last 20+ years have a failure due to oil weight being too thin.

Where have you been looking?! McDonalds?

I see (almost daily) torn down engines with bearing failures, excessive cam wear, scuffed pistons etc, all due to a lack of oil pressure.
Bah - I can't be @rsed any more. :roll:

LouC · **Posted:** Sun Oct 20, 2013 4:15 pm

Part of the confusion and disagreements, is the fault of the companies marinizing the same engines. They all have recommended different oil/viscosity for basically the same engines.
Merc used to say no multi vis besides 20w/50 or their 25w/40, or a straight weight.
OMC always recommended straight 30.
Volvo has changed the most, from straight 30 years ago, to syn 30, to syn 10w30, to now 15w/40. Crusader (straight inboards) recommends 10w30 below 50 and 15w/40 above. BUT, here is an interesting bit of information...those Crusaders use engine oil coolers. I think that makes a big difference, if you have a Merc or a Volvo that uses engine oil coolers, then a multi vis oil may work fine. But if not, I think the Merc 25w/40, or straight 30 or 40 provide the best protection against shearing down out of grade. The good thing about using what the manufacturer recommends, is at least you know they tested that in the engine you have, for them to recommend it and keep the warrantee in effect. Experimenting otherwise can be risky.
Does anyone know, if modern Merc or Volvo I/Os use engine oil coolers?

Maybe what we need on this site is like what they have on Bob is the Oil Guy, people posting used oil analysis of their engines oil so you would know for sure. Otherwise its just a bunch of conjecture.

230 Mike · **Posted:** Sun Oct 20, 2013 5:19 pm

Oh there you go, somebody just had to mention BOB. :evil:

Soon this thread will be 73 pages long.

deafwish · **Posted:** Sun Oct 20, 2013 7:47 pm

The main reason monograde oils were used in the past, was due to the unreliable performance of 'VI Improvers' in multigrade oils.
Most quality performance oriented oil manufacturers now use a 'starburst' style VI Improver, that has exceptional shear stability; which is critical in marine petrol engines.
Monograde oils have great shear stability, but not much new technology has gone in to mono's of late...

TX H210SS · **Joined:** Thu May 27, 2010 9:10 am **Posts:** 1488

[quote="ric"]All vortec engines are roller cam (since the mid 90s). Just look at your valve covers. If it has the bolts holding them down in the center and not around the edges it's a roller cam engine.

Not....I had a 69 Chevy 350, 83 jeep 6 Banger and a 1953 ford tractor plus a yanmar diesel that all have had bolt
thru valve covers.

ric · **Posted:** Sun Oct 20, 2013 8:41 pm

Well if you want to see the confusion of what oil to run...

GM says one thing. Volvo says another. Mercruiser has something else to say.

What does it all mean? It means nothing. Just put oil in your motor. Change it regularity. You're fine. Doesn't matter what brand, weight, or make. Just change it.

deafwish · **Posted:** Sun Oct 20, 2013 11:13 pm

230 Mike · **Posted:** Sun Oct 20, 2013 11:40 pm

hutch9900 · **Joined:** Tue Mar 22, 2011 7:14 pm **Posts:** 456

taz42169 wrote:

Did an oil change a few weeks back. The Volvo dealer said VP has switched to synthetic 10w-30. At least in our boating area.

That is what I got from Volvo for my 5.7 Gxi-G as well. Its also listed in the Volvo engine manual for my engine.

kd4pbs · **Joined:** Thu Sep 05, 2013 10:34 am **Posts:** 350

I use Astroglide in the winter, KY jelly in the summer. I've never noticed any ill effects such as excessive smoking, too much blow-by, or a seized crankshaft. :wink:

Iamwildman · **Posted:** Mon Oct 21, 2013 10:45 am

Thank you all for the suggestions. I did the drive to the Volvo dealer and they gave me 10w 40 Volvo syn oil.
I will say that this thread is a prime example as to why I asked in the first place, everyone has a different opinion on what to use. I do tend to agree that oil is oil but I do like to stick with what the manufacture recommends.

ric · **Posted:** Mon Oct 21, 2013 11:06 pm

MC and VP have ties to oil companies so what they tell you to run depends on who's writing them a check that year.

On the otherhand, General Motors does not. I listen to them.

www.iFourWinns.com

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