mistake using automotive-type motor oil?

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bluebelly

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Aug 15, 2007
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A neighbor has just found out the hard way about what the difference between marine hd motor oil and standard automotive oil. He has a boat with 8.1 volvo pentas that are 2 years old. For the last 200 hours he has changed his own oil using penzoil or castrol 20w40. He just discovered that the "top end" of his engine has been starving for oil because of foaming. A factory volvo technician confirmed all of this, even changing the oil in one engine and not the other and running the boat for about 20 minutes at 3800 rpm with the owner on board, then showing the boat owner the dipsticks and sure enough the engine with marine oil was normal and the other engine with automotive oil was full of bubbles. It appears that marine oil has a anti-foaming agent added to it to prevent "foaming" during extended high rpm runs. Has anyone else run into this before?
 
I have always used straight SAE 30. Never had any problems.
 
I have been boating and doing boat maintenance for the better part of 40 years and have NEVER heard anything like this???? Next your going to tell me there is a difference between Diesel oil for trucks & Boat motors......
 
Petep said:
I have been boating and doing boat maintenance for the better part of 40 years and have NEVER heard anything like this???? Next your going to tell me there is a difference between Diesel oil for trucks & Boat motors......
Click to expand...

Never heard of it either....you're not a Quicksilver or Volvo Penta oil salesman are you?:huh:
 
Oh CRAP! I've been buying Valvoline Premium Blue from the local NAPA store for years...
 
sarcasm aside, (I already admitted to being a little drunk) the problem with that is that boats aren't necessarily run at higher RPM than cars.

My car redlines near 7,000 RPM, and if you've ever driven in Michigan, you'll believe me when I say that I get the chance to wind it up on a regular basis. I have yet to use marine-grade oil in it...
 
Actually there is such a thing as oil foaming. check it out on google.

It usually is a result of moisture or some other liquid contaminate in your oil. The best way to fix it is to have the innards of your engine steam cleaned and baked dry. This is also probbably the most expensive way. BUt you want to make sure ALL of the contaminates are removed from the engine.

There are also anti-foaming agents you can buy.


I agree tho, Ive been using the same 30 weight I use in my truck for years.

Hope this helps
 
Maybe I am the exception here but I wouldn't use anything other than the oil recommended by the manufacturer. In my case that's Mercruiser. It is my understanding the oil is formulated differently than automotive motor oil to hold up to higher RPMs and loads than a car would usually endure. Car engines don't run at sustained high RPMs for hours at a time. Nor do they run at the same temperatures. Besides, how much more is Merc's oil going to cost you in any given season? For me I might change mine twice a year and I don't feel like taking a chance on my oil just to save $20 bucks a year at the possible expense of damaging my engine or considerably shortening it's life.
 
I agree that using an oil recommended by the manufacturer is a good thing. For example, Cummins worked with Valvoline on the Valvoline Premium Blue product line and that is what they recommend and what I use. However, I don't recall seeing anything about "marine" or "roadside" differences and they are the same. I know that in the diesel crowd, Shell Rotella is popular and people buy that at Wal Mart. I prefer the fancy schmancy designer oil.

Whatever oil you use, it better meet or exceed all the ratings the manufacturer recommends.
 
and I've been thinking Mercruiser Oil isn't good enough for my boat engines, and was thinking of going to Mobil 1 Synthetic instead.

It almost sounds like this person might have had a low grade oil maybe, or one with some sort of cleaning solution in it?

-Garth
 
VTSeaRay said:
and I've been thinking Mercruiser Oil isn't good enough for my boat engines, and was thinking of going to Mobil 1 Synthetic instead.

It almost sounds like this person might have had a low grade oil maybe, or one with some sort of cleaning solution in it?

-Garth
Click to expand...

Mercruiser makes a Synthetic Blend.

By the way, here is Merc's recommendation on which oils you can use. Notice that they also say "Any NMMA FC-W oil" as an alternative to their own product.

http://www.mercurymarine.com/serviceandwarranty/mercruiserfaqs/fueloil.php#1124
 
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I was also dubious of the car vs boat oil thing until I started looking into the issue. My conclusion is that I will always get NMMA FC-W certified oil for the boat, most likely from Mercruiser. It is not alot more money, and I keep receipts to show the maintenance is done as per the book. Most importantly, I know that the FC-W rated oil is not junk... take a look at the process and testing that goes into FC-W rating..

http://www.nmma.org/certification/local/downloads/documents/FCW-ProductApprovalSys _9.06_.pdf

If I were buying a boat, I would prefer the owner had used the NMMA certified oil now that I know more about it. (OK, now go ahead with the emails saying NMMA is a bunch of marketing hype...)
 
VTSeaRay said:
and I've been thinking Mercruiser Oil isn't good enough for my boat engines, and was thinking of going to Mobil 1 Synthetic instead.

It almost sounds like this person might have had a low grade oil maybe, or one with some sort of cleaning solution in it?

-Garth
Click to expand...


Mercruiser now produces a synthetic blend. It is approved for all Mercruiser 4-stroke engines (don't quote me). I use that in my engines. By going to the dealer and buying it in bulk (I pump it into a 5 Gal plastic gas container), I save several hundred dollars per year. In bulk, I pay about $5/quart. If I buy it in individually wrapped containers, it costs around $17/quart.
 
My neighbor just e-mailed to me the response from volvo and there is a different SAE rating for oils that are to be used in marine HD applications. On every container of oil there is a "round" SAE logo that discloses the ratings of that specific oil. The additive that volvo is looking for, and I suppose any other manufacturer of marine engines, will suppress foaming which is likely in high-load, high-humidity conditions. The oil that my neighbor used in his boat did not have the proper "SAE stamp" on the bottle. The technician did comment that he sees this on generators alot more than propulsion engines because of the continuous use vs. intermittent use.
 
Dave S said:
Maybe I am the exception here but I wouldn't use anything other than the oil recommended by the manufacturer. In my case that's Mercruiser. It is my understanding the oil is formulated differently than automotive motor oil to hold up to higher RPMs and loads than a car would usually endure. Car engines don't run at sustained high RPMs for hours at a time. Nor do they run at the same temperatures. Besides, how much more is Merc's oil going to cost you in any given season? For me I might change mine twice a year and I don't feel like taking a chance on my oil just to save $20 bucks a year at the possible expense of damaging my engine or considerably shortening it's life.
Click to expand...

I'm with you on this one, Dave. I guess I'd rather spend a little more on oil, and not have any issues comes time for warranty work. I'd hate to have something major blow and have them tell me, "well geez, you're using the wrong oil". Just insurance, I guess.
 
Absolutly, If you are under warranty, you will most certainly want to use the recommended oil, what ever that may be. In my case. The warranty expired about 27 years ago, and the engine is a 351 windsor, which was also a car engine. As for RPM's i usually dont even hit 3600, so its not running any faster than in a car. I will agree that its under a heavier load, but of all the probs I had last summer,,,,oil wasnt one of them!!!!! Ha!!!
 
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