? Diesel Oil/Gas Oil

[Ed in FL]

I was recently pointed to this site for the great info on oils and have been searching past posts for the above subject, what difference is there between Diesel rated oils (CH-4) and Gasoline rated oils (SJ) and an oil that is dual rated for both of these.

The reason I ask is this. I have a pair of 140 hp 4 cylinder Suzuki 4 stroke marine outboard engines and am plainning on doing an oil change. The manual states as long as the oil is SE rated or better the oil is ok to use, and the preferred viscosity is 10W-40. Well, I stopped by the dealer and picked up a quart of the Suzuki brand 10W-40. What was interesting was the dual designation on the back label of both SG and CH-4. It was my belief that the CH-4 designation indicated different additives are in the oil to pass the API diesel tests. I picked up a bottle of the SuperSyn Mobil 1 10w30 off the shelf in my garage and noticed that it did not include the CH-4 designation, and I assume is not to be used in a diesel application that requires CH-4.

These marine 4-strokes run relatively cool and top rpm is 6200. Is the Suzuki oil relying on the diesel additives to keep the engine clean since they do not get as hot as the new car engines, hence the CH-4 designation?

Was thinking of going with Delo 400 15w40 instead of the Suzuki oil ($3.19 quart). What do all of you oil experts think?

Thanks
Ed

 

[G-MAN]

Actually, SL is the current top gasoline API rating, and CI-4 is the current top diesel rating. Most good fleet oils (like Delvac, Delo, Rotella) will be rated SL/CI-4 meaning they meet the performance requirements for both. In general, an oil that is rated SL/CI-4 will have a more robust additive package with more detergents and dispersants than an oil rated SL only.

A good 15w40 SL/CI-4 oil (Delvac, Delo, Rotella, Schaeffers) would probably do fine in your boat engines.

 

[sprintman]

Delvac 1 will keep the engines clean. Call Mobil tech to see what they say.

 

[Ed in FL]

Are there any downsides to using a Diesel oil in a gas engine? Too many dispersants or other additives?

I may switch to a Delvac 1 in the future, wanted to put a few more hours on the motors before switching over to synthetics. Thanks for the info on Delvac 1, I'll check into it and give the tech a call when I get a chance.

 

[darrenc]

In my opinion no, there is really no down side to using a duel rated oil. the “diesel” oils (Rotella, Delo, Delvac) sometimes have more sulfated ash due to their robust additive package and resulting high TBN, but not enough to matter or adversely effect a gas engine. I use these types of oils in my I/O Volvo Penta boat motor, as do many others.

If you are going to go dino, I prefer the Delo or Delvac. Both have great base stocks with good additive packages. If you go synthetic, I’d go with the Amsoil Heavy Duty Diesel and Marine Oil, or there 10W-40 or 0W-40 syn oils. Synthetic Delvac 1 5W-40 would also be a good choice.

 

[Ed in FL]

thanks for the info guys! I bought my last case of Suzuki oil yesterday and will probably go with Delvac 1 this summer when I have another 100 hrs on the motors.

Ed

 

[TexasTDI]

quote:

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Originally posted by Ed in FL:
thanks for the info guys! I bought my last case of Suzuki oil yesterday and will probably go with Delvac 1 this summer when I have another 100 hrs on the motors.

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Another good choice is Amsoil 15w40 Synthetic Heavy Duty Diesel and Marine Motor Oil. It meets API SJ and CI-4 and would work great in the Florida summer heat. It's the oil I use in my diesels in the hot Texas summers. And I'd use it in my boat too...if I had a boat.