rx8 gets hot
 

Hugh long story but basically....2004, 81k miles...has new radiator. New thermostat. Fans are working an temp gauge checks out...doesn't get hot idling ...but does on freeway (80+ MPH) turn heater on it cools off...(actually yesterday was so pissed it was still getting hot I didn't turn heater on it got halfway between half an hot an started coming down in temp on its own???? ) wtf!!!! Please help..any suggestions??

automatic or manual?
have you checked the coolant levels? what type of radiator and thermostat did you have installed? OEM or aftermarket? If aftermarket, please let us know brand / model.

your temperature gauge is moving ?
that gauge is not accurate, it is programmed to move to the same spot every time and stay there once the car has reached operating temperatures (somewhere in the 150° - 220°F range)
if the needle moves, your car is already overheating.

you mention it 'gets hot' on the freeway at high speeds.
are the oil coolers okay? is there anything blocking air flow?
what about the plastic under tray? is that broken in any way? (air could be escaping and not getting to the radiator)

Hay OP, You live in Phoenix so you just about have to expect to see your 8 over heat. If your interested in why and what you can do to control it, see Black Halo Racing.

Manual....factory radiator..dealer thermo... nothing blocking airflow.....have not checked oil coolers( will when get home tonight) an the plastic under is gone...has been for a few years now ( just haven't had the money to replace an hadent had any problems ....???till now) I will explain details when I get off

thats likely some of your problem
air isnt being pushed through the radiator properly for one

No undertray will definitely ef up highway cooling...

replace the tray smarty

that right there is your problem.
the air is travelling at high speeds and instead of being trapped with the undertray and being forced up into the radiator to cool your vehicle, it is escaping.

get this replaced ASAP, your car is overheating and you are causing damage to your motor.

I will check out black halo racing....thank u. ( but I have had the car since 2004.. I'm original owner have always had car in AZ an have never had overheating problems...till now)

and the last time you flushed the coolant system?
regardless of how long you've had it, you NEED an under tray on your car since it's summer and you live in the DESERT.

OK.....ill try it....thanks for the info ( I guess I didn't consider that as a culprit due to its been gone for 2-3 yrs now an has made no sufferance....all this getting hot crap didn't start until I replaced the Radiator???? Which needed replaced due to the little nipple broke off that goes to the overflow bottle ...after that is when it started getting hot)??? But ya...that's something I had forgotten about....will post what happens after I put it on on Thurs...

random question but what coolant did you use? 50/50 mix?

Without the undertray you will overheat easily.

he speaketh the truth

ya......... i used 50/50 mix......????

K all....I put the plastic under engine cover back on......an it STILL gets hot!!! No change.......Now what???