I'm looking at buying a 2004 RX-8 with 67k miles. The new 2010 RX-8 I drove has an upgraded tach with a second red line that is a function of the engine's operating temperature. I assume this is to get the driver to go easy while the car warms up. Since the car is in Minnesota, there is a good chance that it has seen some cold days, but it still sounds and drives as well as the new car.

I have never owned a rotary so I'm not 100% certain what is or is not a good idea for me to check out before making a purchase. I'm also not sure how many miles these engines can do before needing a rebuild. Given the environment the car has seen, the number of miles, and the good sound, is it worth spending $120 to have a compression test done?

 

It would be worth it if you're buying one used. If the compression is low for that motor then that would have an impact on the selling price.

All RX8's have limiters for when the coolant is cold. The S2 simply shows the redline.

 

Since the 04 engine has a 100K warranty so long as it drives well I wouldn't get that test done till 99,000 miles.

 

For peace of mind I would think so, on an older one. I recently bought one and decided against the compression test and just did a test someone else here suggested. They said to take it for a test drive and accelerate hard and if it puts a smile on your face from 4k to 9k then its fine. If it doesn't feel like it has much power in that range then theres probably something wrong with it.

Of course I havnt owned this car for more than a week so I might be wrong, its just what I have read on here.

 

depends on where you're located, some people have the official Mazda compression tester (**** cost a ton if you want to buy it new, like 1500 bux) that you can try it on for maybe 20-30 bux.

But if you ask me, meh, I would say its probably not worth it for now. Cuz what if it checks out bad ? You wouldn't buy it and your 120 bux is now gone. If it checks out ok --- then whats the point of spending that money?

Just check and see if it starts HOT fine. you're in Minnesota right? so I guess you can just drive it like you stole it for 20 minutes, then seats in traffic(real slow traffic) for another 20 minutes. Turn the car off for 30 seconds, Start it again, does it starts fine and fires right up? if it does then this car should be ok and do the compression test when you reach about 99K miles as expo suggested.

but if it takes a long time to crank and you're sure the battery is ok. stay away.

 

How bad does the compression need to be for it to be covered by the warranty?

 

anything in the 6 means fail.

low 7 should fail. but some "stupid" dealership will consider it as ok to avoid the warranty work.

anything more than 1 between the 2 rotor means fail.