I'm going to buy a bottle of 5W-20 to keep in my trunk. I was wondering what brand mazda dealers use? Does it matter if I use the same brand that they put in at my service?

I've read that it's best to stick to a single brand in case the different additive packages don't work well together.

Originally posted by Rotary Titus
I'm going to buy a bottle of 5W-20 to keep in my trunk. I was wondering what brand mazda dealers use? Does it matter if I use the same brand that they put in at my service?

Hi Rotary Titus,

Here's an opinion for you from CITGO (http://www.citgo.com/Products/LubesOils/MythsAboutEngineOils.jsp)

"Myth: You can't mix brands of motor oil.
Fact: Mixing brands is not the best practice because the additive systems in each may be different and when mixed may not function as efficiently as desired. However, no serious problems will occur if you must add a different brand of equivalent quality between oil changes. It is very important to maintain proper oil level. "

I'm personally going to continue using my case of Castrol in between oil changes regardless of what brand oil the dealer uses during my oil changes. It gets too complicated logistically otherwise.

Here's another reference (http://news.theolympian.com/specialsections/Auto/20020413/5578.shtml) that says basically the same thing.

regards,
rx8cited

I see....
thanks!

All the oil companies are pretty much using the same kinds of additives anyway nowadays, just in different quantities. Its not going to hurt anything.

I checked with my dealer to see what they use when they change the oil (Motorcraft 5W-20 Blend). I now carry that type to top-off the oil. I am at ~1800 miles, am down 1/2 quart, and haven't added any yet.

motorcraft eh?....
any recommendations on the "best" oil without going synthetic?

I know my dealer uses some form of Castrol 5w20...just put a bottle in...so do not all dealers use the same?

Originally posted by Rotary Titus
motorcraft eh?....
any recommendations on the "best" oil without going synthetic?

My favorite flavor ice cream .... um motor oil is Castrol GTX 5W-20. :D.

so then my question is - because my old car mechanic asked me - are we NOT to use synthetic oil in the RX-8? Stick to the 5W-30? I'm at 2,200 and down about 1/2 quart - haven't added anything yet. Want to do it right from the get go. Thanks.