Mixing oil grades..... e36 m3 evo - 5w-40 or 10w-60

[dimebag_from_hell]

I am servicing my e36 m3 evo at the moment.

I have some fully synthetic castrol tucked away, its 5w-40. 4 litres of it.

The previous owner had the car serviced by a bmw indy, he reccomended 10w-60 to him. I have never used it on a m3 evo and I was always under the impression that 5w40 was the one to use.

Anyway, the car came with a 2 litres of the castrol 10w-60 oil.

Instead of me going out and buying more oil, could I just stick the 4 litres of 5w-40 in and then the rest 10w 50? I have done this before with diesels and the likes, but with an engine such as this I am thinking before I do it.

what does everyone think

[maxfield]

Castrol TWS 10w60 is the oil you want.

Do not mix oil. It's an M engine. Not exactly an engine you can pick up for £50....

[Blitz]

Is that your £2k m3?

[dimebag_from_hell]

Castrol TWS 10w60 is the oil you want.

Do not mix oil. It's an M engine. Not exactly an engine you can pick up for £50....

I was under the impression that 10w-60 was for the e46 m3 and not the e36 m3 and bmw are simply specifiying 10w-60 now for the e36 m3 because thats simply what they have in stock.

[Speedtouch]

Castrol TWS 10w60 is the oil you want.

Do not mix oil. It's an M engine. Not exactly an engine you can pick up for £50....

This. Why risk potentially f*cking the engine for the sake of a few quid's worth of oil?

[dimebag_from_hell]

Castrol TWS 10w60 is the oil you want.

Do not mix oil. It's an M engine. Not exactly an engine you can pick up for £50....

This. Why risk potentially f*cking the engine for the sake of a few quid's worth of oil?

I am not risking anything BUT I am interested to know if its going to make a difference?

I know guys running semi synthetic with regular oil changes, I think these engines are more hardy than people make out.

I am also interested to hear if 10w60 is safe to use.

[harry_p]

Lots of e36 m3 owners use 5w 40 without issue. I do believe it's the grade people like opie supply for them too, and what you get if you put your reg into the euro car parts site.

However, I have used 10w60 in mine for the past 70,000 miles, and know the previous owner used it too, so it's all it's used for the last 90,000 miles, and is now coming up to 230,000, and gets driven hard. So, in my opinions 10w60 is a perfectly safe oil to use. ( don't blame me if you use it and it goes pop the next day! )

There's no real issue mixing oil, just that topping up a 10w60 with a 5w40 will effectively thin it out, so it will start to behave more like the thinner oil.

The oils themselves will mix together fine, if they didn't you'd have to strip and flush the engine every time you did an oil change to make sure you got every drop of the old stuff out.

[dimebag_from_hell]

My engine is sub 90k, running very well with no noise from the vanos at all so it is obvioulsy happy with the 10w 60 the previous owner is using.


Ummmm will have a think about it.

[harry_p]

Keep an eye on euro car parts/ car parts for less. Oil is often included in their 'sales' and around £30 for four litres of 10w60, so I tend to stock up when it's cheap.