Ok, went to the dyno couple of weeks ago and the car got a bit hot. Hot enough to puch coolant and according to my logger it was about 230 dgrees. I had never ever sen it overheat before, so i was a bit miffed as to why this was happening. I drove home ad kept an eye on the gauge. Perfectly fine and i was doing 120+ almost the entire way. In fact, the gauge hasnt even budged since then, it's never goten hot. Even in warm weather, idling for 10-15 minutes at a time etc. So this weekend i decide I'm gonna change my coolant just for feelgoods.

change the coolant and drive around. All seems well. I let the car cool down and there is no visible coolant in the resivoir, and open the rad cap and theres no visible coolant there. I fill it up, and go for a couple hard passes. Stop the car and pop the hood immediately, and the coolant tank is overflowing. I let the car cool down again and once again, it has pushed enough coolant so that theres no visible coolant in the reservoir and no visible coolant in the rad. It takes about a quart. I fill it up agian let it idle, rev the engine up and down and tem gauge is steady as a rock.

I want to say it's ok, but my gut instinct is telling me this isnt normal. I dont understand how i could have a HG leak if the temp gauge has never shown hot except that one time on the dyno, and that is it. It never shows hot, and the fans all work properly. it comes on, and runs for abou 30 seconds and shuts off. The hot air from the AC doesnt feel overly hot, it just feels pretty warm. Dunno what to do, any hel p would be appreciated.

 

Is the fan coming on? There was a recall on the fan controller. The car is going to stay cool at speed, it's once you slow down/stop it's going to overheat.

 

When you change the coolant you must fill the system while the car is running and let the coolant get pulled through the engine when the thermastat opens/closes, i would let the fan kick on while idleing about 3-4 times to show the thermastat opened and closed 3-4 times, then you should be at the full line on the resivoir and all the air is out of the system. (note: while filling the system, you should see bubbles comming up through the coolant in either the resivoir or rad.)

 

Also, you prob ran a little hot on the dyno due to lack of airflow. You have to remember you are not moving on a dyno, and adequate air flow to the front of the car is nessasary. Your car is used to seeing 100mph air flow to the entire engine at those RPM's on a dyno.

 

well, no other evo has overheated on that dyno, plus they have a huge fan blowing right up against the IC and rad.

bolsen, ive already had that fan controller replaced and yes te fan kicks on and off when necessary.

noticed that i have tiny black flecks of stuff (not oil maybe soot) floating around in the fluid.

 

your head gasket is most likely toast. if you keep driving it around its gonna eat away at your cylinder head. I would get a new gasket, studs and head resurfaced if i was you. most likely it was blown when you took it to the dyno, causing you to overheat.

 

bump

 

What your describing is a head gasket problem. The exact same thing happened on my 1st gen. Pull the head, replace the gasket and put some strong head bolts in there.

Derek

 

thanks for the bump seth.

guess ill be doing a head gasket swap here in the next couple of weeks.