Hello.

I have been checking data sheets from gasoline and diesel engine lubricants, and as far as i can see, differences between them are not clearly defined.
In Mexico, many taxi drivers use to add diesel engine lubricant to gasoline engines, and they are satisfied with the performance obtained.
Is there any detailed reference to read and find any significative difference between them? Can you send it to me or tell me where to look?

The life span from a diesel engine lubricant is longer than any gasoline engine lube, why I should not use it on a gasoline engine?

Would i have longer drain periods?

Thanks for your time reading this.

Hello there Ariel,

Well, you can use a diesel approved lubricant in any gasoline engine, but not the other way around. The big differences between the two are viscosity range (usually diesel oil is a straight 30 weight, or a 15w40, or 10w30), levels of additives for engine protection (diesel oils are usually higher), and TBN levels (again, higher for diesel, as to combat soot levels from the combustion process).

The big reason that most in the US usually don't use a diesel oil in a gasoline engine is catalytic converter poisoning from any oil consumption issues. ZDDP, which is usually in high levels in a diesel rated oil, can build up in a cat, and cause premature failure of the part. Mind you, this only comes into play if oil consumption is an issue. I've been using a motorcycle racing oil in my car, that has levels of ZDDP through the roof, but I have no consumption, so I'm not too worried about failure of an emission systems part.

Longer drain intervals are both a personal choice AND a system backed up through oil analysis of the oil in the crankcase after so many miles or kilometers. You can usually leave in diesel oils longer, as they are designed by nature to last longer, but I wouldn't also blindly say that I would leave it in the crankcase for say, 15K miles, without doing an analysis, to be sure that the lubricant is still doing it's job, or if the additive package is spent.

Hope that this helps somewhat.

Amazing.

That clearly states the question.

I heard that it was not recommended, however i did not get to know why.

Now, i can see clearly and when i face that question again i will reply in a proper way...

If that is the main problem, then it can be helped a little bit with the CJ lubes, as far as i know, they have lower levels of ZDDP.

Thanks a lot for your kindness.

Here is another thing that might help. Unfortunately, it doesn't list the levels of additives, but can at least give you the break down of the API Service category classifications. Both SM and CJ-4 oils have significantly lower levels of ZDDP, as per our new emission parts longevity concerns.

http://www.upmpg.com/pdf/api_motoroil_guide.pdf

http://www.carro.myffi.biz/en/index.php?option=com_cont...view&id=28&Itemid=41

Save your money and don't bother with fairy dust in a bottle products that promise the world. Pick a high quality lubricant from the start and you won't have to add anything to it.

A lot of talk only about oil here...but please take into account that the sulphur content and/or general quality of the petrol/diesel in Mexico can be very different...

Yes, sulfur levels are now a major concern in the US in the diesel fuel industry. Current 2007 engines require the use of 15 PPM sulfur diesel fuel down from the 500 PPM of last year. Use of high sulfur fuels in modern diesel engines in the US can prematurely poison/plug up a diesel particulate filter.