Oil question (short)

[4.8isX5]

Just a quick question for the more technical guys on here,

I run 10w-40 mobil1 full syn now,, its time for an oil change so for the winter i want to run 5w-40 mobil1,,

Thing is its labeled for turbo diesel? Im assuming it should work just fine as the 10-40 one im using now and they just label it for the diesels since thats what most of them specify to use is 5-40,,,

Let me know cause i want to pick some up tommorow.


Thanks.

[g300d]

That's fine IMHO.

The diesel Mobile 1 just has some differences in the additive package for diesel applications (soot dispersants and others that escape me now) but will work just fine in a gas motor AFAIK.

[4.8isX5]

Thanks,, i actually just looked it up online as well,, guy using it in a e90 and even did lab tests, stronger oil, better anti-wear properties, and for all the people say to use bmw approved oil, it seems like its more for emissions from what ive read, heres a link to the thread for anyone else who may have this question and is wondering.

Mobil1 Turbo Diesel 5w40 Works Great in Our Engines!

[g300d]

Yup I do recall them being actually better than the regular Mobil1 in some aspects.

Thanks for the link, good to see experiences of others with this oil in BMW-specific applications.

[Ricky Bobby]

I run Shell Rotella T6 5w-40 which is advertised for turbo diesel trucks, but countless reports of it working good in gas engines. Go with the 5w-40 Mobil 1 you might find you'd like to run it year round

[dkl]

Just curious, why not run Mobil1 0w40, which is advertised for gasoline engines?

[JCL]

Sure, some properties of a diesel engine oil can be better. But others will be worse. The base oil is the same, the additives are what is changing. Diesel engine oils are designed to perform well on the tests designed to highlight characteristics common to diesels. Similarly for gasoline engines. Many of the oils will be tested to both specs, so you can actually try and discern what you are giving up by going one way or another.

Use the Mobil 1 as an example. 15w-40 diesel oil meets the ACEA E7 standard. This is designed for heavy trucks. But it also meets the API SM standard. Mobil 1 0w-40 for gasoline engines meets the SM spec, but also SN. Now we can compare them. What is the difference between SM and SN? SN has improved performance relating to exhaust aftertreatment, sure. Probably not important in this case. However it also has improved performance relating to piston deposits and sludge control. Those are important. Finally, it stands up to ethanol better. Not important for diesel engine oil, but increasingly important for gasoline engines in North America. Now, this isn't to say that the diesel engine oil can't match the piston deposit and sludge control numbers, just that it doesn't meet the spec that includes those standards. It may not meet the spec for a completely different reason, such as inclusion of a chemical that exceeds the SN limits. But I would think about the ethanol factor. I believe that ethanol is a much bigger issue, myself. If you are always buying fuel that has zero ethanol, then this is all much less of an issue for your application.

Each oil (diesel and gasoline) is optimized for a different application. One is not 'better' than another overall, and you can't just cherry pick the individual characteristic you like and say that it is therefore a better oil. It is a different oil, and for everything you gain, you give up something else. It may work just fine. I personally think it very likely will. But I disagree strongly that a diesel engine oil is more suited to your BMW gasoline engine than an oil that is designed for it.

[4.8isX5]

Good points JCL. But for the most part, the way the cars used is normal driving and the only ripping around it gets is during meets and the occasional full 3rd gear windout, no one here is running the engine 6k rpm half the day, like for example race engines, so i really feel alot of the things are not going to matter that much.

I do agree for example never using cheap dino store brand oil, versus a reputable full syn like mobil1, castrol, etc. There are vast differences there.

But the diesel provides more anti-wear additives, zinc and other stuff, along the weight of the oil, im sticking to 5-40/10-40 maybe will end up running this year round the 5-40, because so far the steps i have taken to reduce my smoke and oil consumption, it has made worlds of difference since it was bad compared to now..

Before i could eat a quart 600-800 miles.. Now i go for 1750+, oil smoke is almost non existant unless i purposefully idle it when hot for over like 12-15min.


Other then those points (which makes it the best option for me), it basically comes down to just changing the oil/filter frequently and its a small investment to pay versus running it real long and the risks for engine.

So perhaps an oil may not meet bmw longevity spec, but i would never care cause the only reason i ran my last full syn mobil 7k is because of some longer trips and the fact that the x holds more oil then standard cars. Normally i run full syn for 5k (granted its cheaper when the cars only req 1 5qt bottle), but its cheap peice of mind and keeps the engine working great.

[JCL]

Fine, but all those points are about using a heavier weight oil like 15w-40, and changing it regularly, but are not about using an oil optimized for diesel engines. I thought that was your original question.

How are you judging that the diesel-specific engine oill is providing more anti-wear additives? A diesel won't usually run at higher rpms, so the wear tests will focus more on low speed operation. The diesel engine tests focus on soot, for example. That is an issue for diesels, not gasoline engines, IMO. Do you consider those tests more relevant? Look at the different tests manufacturers have to run to meet an A3 spec vs an E7 spec.

There isn't a relevant BMW long life spec, which is what I think you are referring to as longevity. The last one that applied to petroleum engines such as yours was the LL-01 spec, and it is now twelve years out of date. Even BMW has stopped referring to it in owner's manuals. Just use a good API spec in the viscosity of your choice (within reason). But I wouldn't give up API specs or accept a lesser lubricating oil just to get a bottle that says optimized for diesel engines on it. That doesn't make sense to me.

[g300d]

Good points JCL.

LL01 is an old spec, but personally I will not use any oil on my particular BMW's engine that is not LL01 approved.

My understanding of the LL01 spec is one of the major characteristics of it is much better anti-shear properties compared to even other synthetic lubricants. BMW engines in particular are very hard on lubricants, and will break down standard formula lubricants in short order. It seems bourne out in reality where you see many BMW engines that follow the on-board computer's service intervals build up nasty gunk in the lube system, some to the point of engine failure, even when using factory-approved lube! I dont follow the factory indicators and just change my oil at fixed intervals, which a lot of experienced BMW owners also recommend. But I stick to LL01 lubes.

There is an LL04 spec, but it seems this spec is more for European diesel engines and their particulate emissions systems, and actually provide LESS protection than LL01. The consensus on the technical lubrication boards I researched this on is to avoid the newer LL04 and stick to LL01 on BMW motors in general, except when otherwise called for of course.

This is for the garden variety older BMWs btw, most of the M's seem to specify a very specific oil and I dont know about the newer vehicles like the F-chassis. BMW may also hve supersceded this spec already, but definitely not with LL04.