i have a 2004 mazda rx8 and i used synthetic 4 a while. It works fine the only bad part is like they said it doeas leak alot

 

i went to the mazda dealership yesterday and i asked the service maneger about the oil on rx8s and he said that you supose to put the factory oil not synthetic because if u put synthetic you can blow the seals. Always use 5w-20 and premium gas.

 

This makes sense to me, because once you get oil flowing through any seal, any pressure you have within the engine is transmitted to the seal hydraulically. I don't have any clue what the right pressure is supposed to be, but let's use 50 psi. If the oil pressure within the motor is 50 psi, then the oil pressure in that gap in the seal is 50 psi, pushing out in all directions -- which forces the seal apart. This is a property of all fluids, and it's what makes hydraulics work.

I've never known a leaky seal to get tighter over time, and allowing more oil to flow through the seal by using a synthetic just seems like a disaster waiting to happen.

I know that if I'm buying a car, and I have a choice between buying a car that has leaky seals and one that doesn't, I'm picking the one that doesn't every time.

 

its only leaky if you put synthetic because synthetic is alot more watery oil then the 5w-20. Since its so watery it leacks through the seals not nesesarly because the leacks are messed up but because your supose to be using thicker oil andusing syntheticalso effects the cumbustion inside the rotary so all you can use to be running how ur supose to is 5w-20 and premium gas to get the best performance out of the rotary