Posted: Fri Apr 03, 2015 2:54pm

Hi folks, I've got a Beta Marine B35. Looking at changing oil. Halfords do a 15W/40 mineral oil for diesel engines. Do you think this should be ok? Or is the cheapest not the best idea? Any recommendations? Cheers, Jeff

Posted: Fri Apr 03, 2015 9:00pm

The 15W40 ONLY refers to the oil's viscosity and that looks about correct for your engine. However of far more importance is the API specification that specifies the oil's performance and I can not read than on your small image. I expect it will be something like API CF or API CH4. Then look in your engine manual to see what Beta recommend. As the API specification covers performance it should not matter how cheap or expensive the oil is as long as the specification is within those recommend by Beta.

Posted: Mon Apr 06, 2015 12:00pm

Thanks Tony. The label on the back says 'API SL CF CF-4 and ACEA A3/B3.' Sounds like it should be ok.

Posted: Mon Apr 06, 2015 12:04pm

...although the manual says the engine needs API classification of CC/CD/CE. Is CF better than these?

Posted: Mon Apr 06, 2015 5:03pm

The word "better" is not specific enough to be used in this context. API CF oil has a higher performance specification. The way ordinary mineral oil is caused to perform to higher standards is by adding a load of chemicals known as an additive pack. In some cases the additives have been linked to bore glazing in lightly loaded engines. Now, once the engine is run in, Beta seem relaxed about the API specification used where as other marinisers are less so. In the case of Beta I doubt using API CF oil will do any harm but I can not advise that you use this oil. My Bukh engine has a similar specification but I have been running it on API CF for some years because it is easier to get hold of at a decent price. As they say, the choice is yours.

Posted: Mon Apr 06, 2015 5:35pm

Thanks Tony. I hope you've had a nice weekend.