A few questions before buying
 

I am looking to purchase a used RX-8 and figured this would be a knowledgeable group to ask a few questions. I have read that using the required 5w20 oil will lead to repeated problems with the motor. Is this true? If it is, what would happen if you used the 5w30? On a particular website i read the average between needing rebuilt is 20,000 miles. The same site said using 5w30 will keep the engine good for 200,000 plus. I appreciate any input you might have and look forward to joining you as RX-8 owners and sticking around to learn what i can. Thank you in advance.

I read that same article a while back but never book marked it and couldnt find it again... IIRC if you dont use 5w20 it voids your USA mazda warrenty.
i was told to use 5W30 in the winter, 10W30 in the summer. but have 5w20 in it from dealer.
Alot of ppl will tell you to use the Search button because there are hundreds of Oil threads. i literally mean hundreds. but alot of the information given goes over my head.

I highly suggest buying a 2006 rx8 model + because the 04-05 are more prone to problems. Theres alot of stickies with information you just need to look for them. good luck :) i bought a 2004 last month, drove perfect on test drive, but when we bought it we found 2 problems right off the bat that was a huge major repair. so just do your homework so u wont get screwed!

oil is not the problem
its when 04 came out the PCM wasn't injecting enough oil causing the problem

So it sounds like it would be best to get a newer one. Thank you for the input.

well depending if its on its original engine or not
many 04 rx8s already have the original engine replaced and flashed the lastest PCM to correct the oil injection problem.

Newer is always better. The flashes were fixed with 4206f (mid 2006) and MSP16 (2008). Make sure those have been done...and the earlier the better. If you give a Mazda dealer (or Mazda USA) a VIN, they can tell you.

It's hard looking for oil advice here. Lots of opinions, way too many posts to wade through. Almost any weight that people recommend is OK for temperate climates. Engine rebuilders (who have seen the inside of these engines after failure) recommend much heavier than Mazda's recommended 5w20. Synthetic is tough because Mazda recommends against it, and there are folks who have been denied engine warranties because they used synthetic. Others have had dealers put in synthetic and say it's just fine.

What's the site that talks of 20,000 vs 200,000? Sounds like a fun place to visit when bored with reading about UFOs and ancient aliens.

Hope you find a good 8. These cars are amazing.

Ken