[stevensonleehk]

Sorry for being really ignorant ... but I've always wondered how different grades and brands of engine oil can affect the performance of our cars. I was always under the impression that engine oil itself only acts as a lubricant +/- coolant in the engine.

Any thoughts?

[phawx]

Originally Posted by stevensonleehk

Sorry for being really ignorant ... but I've always wondered how different grades and brands of engine oil can affect the performance of our cars. I was always under the impression that engine oil itself only acts as a lubricant +/- coolant in the engine.

Any thoughts?

You would be surprised at how much lubricant can do for an engine. You're right, that's basically all engine oil is - it's a lubricant, and the reason why you need it is because inside an engine cylinder, there's no space between cylinder wall and piston (imagine a syringe + plunger), and after repeated cycling the areas of friction create really high heat.

Essentially what the engine oil does is transfer the heat away from the metallic components, and it also carries some of the metallic "filings" away (that + burnt oil + dirt = the gunk you see when u do an oil change) from the areas of friction.

Why does engine oil help performance? Because it reduces the friction inside the engine. Less friction, means more force delivered our by each blow, which in turn means more power going to the drivetrain!

From my understanding, the different grades of oil mean that they have different viscosities (how thick they are) and different specific heats (? don't quote me on the second one). In some engines / some weathers, it's better to use a different type of engine oil. Some oils are designed to handle high heat... others to handle cold weathers, etc etc. If you need anything more specific I'd have to go look it up and we'd probably get into chemical engineering stuff.

Hope that helps and wasn't overly technical / boring?

[stevensonleehk]

Thanks! Any good brands you can recommend then? I'm using the original BMW engine oil that is it put in during our annual service.

Is there a need to change the engine oil in between service intervals, say every 5000km, for better performance?

[NiVeDh]

I use Mobil1 Synthetic 0W-40 European Formula, which is LL-01 approved.

[phawx]

Originally Posted by TrackRat

There will not be any change in performance by changing out oil before it's useful life has been met, i.e. "early" oil changes. Any BMW approved LL-01 oil of the viscosity specified by BMW should serve you well and meet your engine warranty requirements. BMW actually tests the oils to insure their performance before approving them to BMW oil specifications.

Hey Trackrat, I may have a caveat to add to the "useful life" part of this.

You're right about the performance not "increasing" due to an oil change. But I think since dealerships calculate the oil life by amount of KMs travelled OR amount of time between oil changes (even though it's set in the on-board computer I don't quite trust their timeline), the driver's driving style will have an effect on the oil life. For instance if you track the car every weekend or flog it for hours on end at high revs, then your oil life might run out much sooner.

In the end as I said, the oil acts as lubricant and has a barrier effect to flush out dirt and grime, so although there might not be obvious performance increase by "premature" oil changes, it gives you a bit of a safety factor in case the oil wears out prematurely. Just keep checking your dipstick and if the oil is turning dark before it should, change it. This would certainly make sure that the engine is clean and running in good shape.

To O.P., I'm sorry, don't have an oil to recommend cos I just moved from Hondas back to Audi/BMWs recently so not really sure what's on the market.