hey guys and gals, i have a 2003 evo 8.

it wont worm up while im driving, if i let it sit there ill worm up but very slowly and the heat from the blower isn't very hot as it should be.

i just changed my thermostat.

i need help, freezing my butt off diving in the morning.

 

I don't understand. You're car doesn't warm up after driving it for x amount of minutes? But will slowly warm up if idling ? How long when driving does it take to get to operating temps?

 

-Coolant level?
-Heater control knob issue?
-Thermostat?
-Heater Core?

 

why did you change the thermostat in the first place? Where did you get the replacement thermostat from?

 

Bad thermostat, thermostat in up side down, low coolant or it is -100 degrees out.

 

Air in the system after thermostat install?

 

ive had this problem since i got the car.

Chaser_41 yes thats the grazy thing about it. if i let it idle ill worm up to middle and then i start driving it ill drop all the way to cold and stay like that until i park agine.

i thought it was the thermostat so i replaced it. bought the thermostat from NAPA.

could it be that i bought the thermostat that opens at 170 degrees?

-how do i flush the air out of the system.
-i installed the thermostat the way the old one was.
-i am having issues with my heater control knob.

 

-air in the system should make the car run hot, not cold (just from personal experience)

-the heat will be cold because the engine isn't as warm as it should be so it doesn't produce as much heat

-the thermostat is likely opening too low of a temperature. the car isn't warming up because the engine acts as a heat sink (and the radiator) so as you are moving through the cold air, the water is being cooled by colder air. when sitting idle there is no "fresh" air moving over the engine or radiator and thus the car is able to warm up more than when it's moving

check coolant as said, but i'd also pull the thermostat and put it in a pot on the stovetop and measure what temperature it's opening at

 

napa and every other parts store period dont sell evo thermostats you have to get one from mitsu. they may say it fits evos but theyre all for lancers

 

so your problem is your evo had a bad or lancer thermostat before and u replaced it with a lancer one which wont let your car warm up except while standing still

 

ok ill call up the dealer tomorrow and order a new thermostat.

thanks for the help.

ill let you guys know if that fixes the problem.

 

Yeah get a thermostat from the dealer, then when you are filling it back up with coolant, remove the top hose going into the heater core and let coolant come out of the hose for a few secs then put it back on, it helps to get it warm faster.

 

do i fill it with the car running and the heater on hot full blast?

 

I replaced mine with a lancer thermostat and it's worked fine for years...

 

Have the car off, keep filling it until it comes out, put the hose back on, then start it up and turn the heat on full blast and let it run for a few mins. you can also hold the rmps to around 2.000 to 3,000 for a min or so also helps