Oil Again - Mobil 1 0w40
 

I changed the oil last week put in Mobil 1 0W40

I have now read many past threads on oils, and I am now more confused than ever and not to mention WORRIED.

My questions are

1. Is this too thin?
2. Why?
3. What do you use?

and finally

4. Should I change it now or leave it for 6000 miles?

The car is a 2005 WRX modified running around 290 BHP

Thanks

On a newage car: Subaru specify 5w-30 which is even thinner at operating temperature!

At 100°C 0w-40 is pretty much the same thickness as 5w-40, as is 10w-40 and 15w-40. (The specification is between 12.5 to 16.3 cSt @ 100°C )

The real difference is 0w-40 has superior cold viscosity performance. It is also a synthetic which is more durable than semi-synthetic oils that is usually used by Subaru dealers

When reading advice on these forums please in mind that later year cars have different (thinner) oil specifications to earlier cars. Also specific oil requirements and change intervals are dependent on how you drive the car.

If you thrash the nuts of the car and running a higher BHP, then yes maybe a thicker oil like a 5w-50, 10w-50 or 15w-50 maybe more suitable, it really depends on how you drive it. Mobil 1 0w-40 is a good quality oil and is superior to a semi-synthetic oil that a Subaru dealer would fill the car with.

I like 5w-30w Amsoil, I have used it since 1972, never a problem. Highly rated here. 5 w is the rating of how the oil pours at at freezing temperatures. 5w would pour like 5w, however, the oil viscosity is a true 30wt. I will tell you how often I change the oil if you ask?

Everything you wanted to know, but were too afraid to ask :D...

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