So I took my rx8 out for a lil drive and it was somewhere between 90F and 100F, I think 96 or 94, but when I started to drive a lil hard my engine temp kinda shot up to the middle, but when I let off it went back to normal, I run 0w-20 in the engine and I normally don't take it out in the heat. would that oil be the reason why it got hot when I ran it a lil hard? thanks in advance!

 

So those are degrees C.

It's not the oil. Check that your radiator is unobstructed, and you have all splash shields in place.

How fast were you driving and how hot was it? The car should be able to deal with most conditions without overheating. Was the AC on?

 

0W-20 is a very light oil for this car but doubtful has anything to do with the overheating. Check cooling system and ensure your fans are activating. Using a thicker oil for summer driving is a good idea as well. I run 10W-40 at all times because I live in a tropical environment. My opinion I suppose but I never have had any engine issues with it across 4 different RX8's.

 

Yes the AC was on, and I was going about 90 MPH :D and I was at 9k RPM, the Fans were activating but it was just that little time when I ran it hard. Rest of the time it was back to normal and I blast the heat on the AC as well, I am getting an oil change here soon so I might switch to 10W-40 if that's what you use in tropical environments, and when I ran it hard later on again it stayed the same but it was also cooler then too

 

Wait... were you sustaining 9000rpm? Definitely don't do that.

 

Hope you dont keep the RPM's up there often otherwise that will cause overheating. 90 MPH? You on the autobahn or something? Haha.

 

 

I too was dealing with a elevated coolant temp reading at "normal" cruising loads and found that my new "low temp" thermostat was ultra lazy.
so after flushing coolant, low temp oil thermostats (made good difference) and re-packing foam around radiator. I try a new "low temp" coolant thermostat and solved it for the time being.

keep in mind I was scheduling the flush, oil cooler t-stats and foam re-packing anyways. by no means was I just throwing attempts at a condition beyond me.

 

Haha no i wasn't doing that I was just having fun pushing it hard for just that lil bit, but No damage at all from what I can tell, just going from 5k -8/9k rpm on that road really quick, and it still kicks my head into the seat at 5k RPM, and I was actually just on a road with a quarter mile with a very very empty road... couldn't miss the opportunity! ofc I made sure no one was around :D I'm beginning to think it was the oil though because everything else you've listed was completely fine... I'm getting an oil change here next week and see if I can use the oil you like to use since it seems to work very well.. I also do premix with the Lucas stuff too, I'll keep you updated on it if you want and try the same thing again with the better oil, although I doubt it'll be any different.

It just hit 71k Miles too, so I will inspect the radiator here and the cooling system while it's sitting waiting for its oil change