Hi Everyone

I have done a lot o research but never found any good answer.

My cars is from german and its is an 2005 and got 231 hp.

At all services it has got Dexelia ultra 5w30.

Is Dexelia mineral or synt?

Is it better to use Castrol GTX 15w40(mineral)?

I have seen somewere if the cars has used synt oil is not good to go back to mineral oil?

What to do?
In Sweden I have to pay 22 us dollars for one liter Dexelia.
1 liter Castrol GTX is 11 us dollar.

 

Use 15w40

Or 15/20w50

 

The Dexelia Ultra 5w-30 is mineral based oil. Mazda buys this oil from the Total Oil Company in Europe.
Use a real synthetic 0w-30 (like Mazda in Japan), or 0w-40 instead of the Dexelia!

 

At $11 versus $22, use the GTX.

I think the common assertion is the other way around - that it's not good to switch a high mileage car from mineral to synthetic.

Ken