'03 Evo 8 running warm, possible causes?
I'm new to the board and a friend of mine has me doing some work on his car. The problem is that the car while driving the temperature gauge goes ~3/4 of the way up and comes back down. So I check the oil its fine, l checked the coolant its fine but it seems someone had filled with 100% coolant (not premixed). I'm gonna drain it out in the morning and install a new thermostat with water wetter and distilled H20. He had the Iridium plugs changed at a local Firestone and then this... Kinda fishy but who knows... The car isn't leaking or using coolant just the needle goes up to 3/4 during accelation, and then drops back down.

I know Antifreeze doesn't cool as well and we're hoping that the antifreeze isn't dissapating the added heat from acceleration as well as if the mix was correct. Anyone have feedback or input on this?

 

I dont think that is the problem i think your issue is that you need to bleed the system. What i usally do is leave the radiator cap off with the heater on and wait till the thermostat opens and add coolant try that and see what happens.

 

anyone else have similar issues?

 

Fan not coming on when it should
Thermostat not opening when it should
Bad temperature sensor
Bad gauge
Blown HG

 

Sounds like the thermostat. But if you change the thermostat and it keeps over heating it may be the temperature sensor. Also if the spark plugs are not correctly gapped, it will tend to make the car overheat. I suggest pulling the spark plugs out and re-gapping them also.

 

Im with MIGHTYMOUSE my car did the exact same thing because there was air in the system and the air bubbles make your car overheat then go back down