Marine oil in a passenger car engine

Messages
24
Location
Media, PA
So, I know this may be an odd question and lots of people will probably ask "why", but I'm going to ask anyway. In my 1995 Subaru Impreza with the 2.2L and 185,000 miles, I've been using 10W-30 conventional oil at 5k OCI's. I'm working on getting the boat ready for the season and will be running to the marine store to get 25W-40 oil for the boat. They're advertising they have a well known brand of marine oil on sale in the 10W-30 grade. Other than the FW-C rating, is there anything wrong with using the Quicksilver 10W-30 in my Subaru or should I just stick with my conventional SN rated oil? The sale price is about $5 less for the Quicksilver 5-qt than a 5-qt jug of the Pennzoil I usually use. Thanks for the input!
 
Messages
68
Location
GA
You might want to check the Quicksilver oil again. I've seen it in quarts and gallons-no 5 quart jug. Per quart I'll bet the Pennzoil is cheaper.
 
Messages
5,324
Location
Paramount, California
FC-W and FC-W Catalyst Compatible® specs are not nearly as strict as any PCMO or HDEO specs. They mainly test for things like rust etc. that apply for marine engines only. There aren't any engine-wear, engine-deposits, etc., tests. The full FC-W specification is posted here. FC-W four-stroke oil certification program So, no, do not use these oils in your car or truck unless they carry additional specs.
 
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1,605
Location
Muncie, Indiana
Seeing how you can get 5qt jugs of passenger car Supertech full syn for like $15 or 5 quart jugs of Chevron Supreme conventional 10w30 for $12.50 from walmart, I don't get the point of putting marine oil that's not rated for a passenger car in your car.
 

Thunderbolt

Thread starter
Messages
24
Location
Media, PA
Originally Posted by blufeb95
Seeing how you can get 5qt jugs of passenger car Supertech full syn for like $15 or 5 quart jugs of Chevron Supreme conventional 10w30 for $12.50 from walmart, I don't get the point of putting marine oil that's not rated for a passenger car in your car.
I wasn't sure if I could use it or not. That's why I'm asking. I now know it's not rated for passenger cars. Consensus seems to be that it's not a good idea, so I'll just stick to what's worked for the 13 years I've had the car. Thanks to everyone for your input!
 
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6,990
Location
Everett, Washington
Very bad to use the non marine rated oil in boat engines because of extra corrosion taking place inside the engine. Of course climate, and whether the boat is around salt water affects the chance of corrosion. We see engines come in that have pitted cams that had automotive oil inside the engine.
 
Messages
133
Location
Missouri
I've always thought the difference between marine and automobile oils besides corrosion additives is that marine oils are blended with beefier anti-foam additives. Marine engines typically operate at higher rpms for extended periods of time compared to automobile engines so they require additional anti-foam additives.
 

4WD

Messages
16,640
Location
Texas
Originally Posted by oilboy123
Very bad to use the non marine rated oil in boat engines because of extra corrosion taking place inside the engine. Of course climate, and whether the boat is around salt water affects the chance of corrosion. We see engines come in that have pitted cams that had automotive oil inside the engine.
Personally I stick with NMMA FC-W oil for my outboard … but you'll get treated like a fool on this site for not running HDEO instead. You think this pitting happens with something like Delo or Rotella ? There was a marine mechanic in south Texas who did a demo with twin motors and the PCMO side was foaming whereas the NMMA side did not.
 
Messages
6,333
Location
Suburban Washington DC
Originally Posted by David2431
I've always thought the difference between marine and automobile oils besides corrosion additives is that marine oils are blended with beefier anti-foam additives. Marine engines typically operate at higher rpms for extended periods of time compared to automobile engines so they require additional anti-foam additives.
Where does this foam you mention come from? Seafoam?
 
Messages
15,870
Location
N.H, U.S.A.
Originally Posted by Thunderbolt
So, I know this may be an odd question and lots of people will probably ask "why", but I'm going to ask anyway. In my 1995 Subaru Impreza with the 2.2L and 185,000 miles, I've been using 10W-30 conventional oil at 5k OCI's. I'm working on getting the boat ready for the season and will be running to the marine store to get 25W-40 oil for the boat. They're advertising they have a well known brand of marine oil on sale in the 10W-30 grade. Other than the FW-C rating, is there anything wrong with using the Quicksilver 10W-30 in my Subaru or should I just stick with my conventional SN rated oil? The sale price is about $5 less for the Quicksilver 5-qt than a 5-qt jug of the Pennzoil I usually use. Thanks for the input!
Ive been promoting 4stroke mercury marine 25W40 oil for hot rods and muscle car engines as high zddp high hths oils are hard to find "on the shelf" You don't need this for your Subaru.
 

4WD

Messages
16,640
Location
Texas
They do require a bunch if ASTM tests … many are also done for HDEO so it's the closest. Foam, corrosion, the outboard engine test … For whatever reason the OEM's formed this harmonizing agency and it's been around a long time. I buy two quarts a year, so no money to be saved. They are no dogs

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