Seafoam in crank case

Aug 16, 2006
281
Ericson 32 Oregon coast
Not in the oil.

Modern crankcase oils come with an additive package that is precisely developed. Introducing another additive disturbs that package and can even be detrimental. The simple truth is that the best practice for crankcase oil is to change it and keep it clean. Also, diesel engines require oil that is rated for diesels and not just for gasoline engines. That rating is clearly indicated on the bottle, usually in several places. You should be familiar with both the viscosity and API rating that is required for your engine.
 
Nov 9, 2009
69
catalina 25 wing keel rutledge tn.
To Kper, Based on experience. I have owned diesel vehicles since 1992, am an Indian Motorcycle restorer, Harley Davidson mechanic, and have rebuilt several engines. Rotella oil is formulated for diesel engines. A lot of people get paranoid about gunk building up inside of their engines but when you perform a complete rebuild on an engine that has had proper oil changes you will see that additives in todays oil do a good job at keeping the internals clean. Running an engine at too low a temperature can cause carbon buildup. Running an engine with a dirty or leaking air filter can cause premature wear on the rings and cylinders. This is 2014 not 1968 when a lot of oils contained paraffin, thus the term detergent oil. Adding additives can adversely change oil viscosity. Once again based on experience and when all else fails, read the shop manual.
 
Nov 6, 2006
9,884
Hunter 34 Mandeville Louisiana
Rotella T is a diesel and gasoline engine oil.. surpassing CJ-4 API rating for diesel oils and SM API rating for spark ignition engines. It goes in all my 4 stroke motors, lawnmowers, generators, cars, and the Yanmar on the boat.

EDIT: I shifted everything over to that when I saw all the test data back in the 1980's. I worked for Exxon and I got the info from our testing guys at our Sarnia, On location.
 
Last edited:
Jul 19, 2013
186
Hunter 33 New Orleans
Shell Rotella T5 15-40 in Yanmar and Fisher Panda Genset. Changed the oil yesterday. New Filter with every change. Change Twice a year right after Day Light Savings Time starts and right before it ends. Change the oil no matter how low the engine hours I put on the boat. No additives in the crankcase.