In reference to the RX8 oil weight, the owner's manual says to use SAE 5W-20, but the local Mazda Service Department at the dealer where I bought the car uses non-synthetic 5W-30 at oil changes. Is this okay, better, or not recommended for the RX8? Just bought my RX8 and haven't gotten the first oil change yet and I want to use what's best.

Thanks for the help.

RKM

 

been some other threads about this and the 30wt used in other countries

In my view, unless you drive in a really cold area, 5w-30 should be as
good as 5w-20 (5w-30 should extend the time betwen adding oil because
it has some 30 wt mixed with the 5w wt)

older rotary engines had no issue using 10w-30!

 

rkm Also:

I think the oil weight question is blown out of proportion.
Mazda is most likely covering their bases based on the car owners.

For many years drivers in general were told to change oil every 3000 miles and to use
10-30 in the summer and 10w-30 in the winter. It worked well and owners did change their oil to the lighter 10w-30 in the colder climates and in winter use.

Todays, drivers only want to change oil every 7000-7500 miles
(which has been shown to be as good for an engine as every 3000 miles was)

They know that drivers are NOT going to remember, or heed, or want to switch TO the 10w-30 in winter, especially if they are below the 7000-7500 mile limit. So Mazda asks the drivers to use 5w-20 and that covers all the climate situations year round and the oil can be changed only based on miles driven.

The dealership in Arizona gave use 10w-30 when we bought our 8.

 

Castrol SAE 5W--20

 

What's funny is, I quetioned them after I got back to work and realized that the reciept said 5x 30. They called back about 2 days later and told me it was a computer glitch that it would be fixed. I would just like to know what is really in it so when I add extra it would be the same.

 

now, is using Royal Purple okay? my friend from the RX club uses it all the time in this FD....