Just making sure I covered all the bases because at this point that I am in now, I am very positive that my headgasket has gone bad on me. THe reason I am making this post though is because I had one friend of mine tell me to reset the ECU and that it may be a tuning issue. If this is true, how can I check it?

THe Symptoms:

Driving regularly, no overheating issues, although yesterday, after normal driving, I stopped and checked the coolant tank and it was smoking when I took the cap off.

When I get on the gas, coolant overflows from the tank and the temperature rises if I dont turn the heat on, or if I get stuck in stop and go traffic.

BTw, no signs of oil mixing with the coolant from what I can see, and there is no white smoke coming from the exhaust as signs that coolant is being burned.

And yes, I am on stock headbolts. I have the ARPs waiting on standby. I know I know...I should have had them in already.


The Attempts to find the Problem:

I changed out the thermostat, and the radiator cap. I also reset my ECU in an effort, on the advice of a friend, that a tune-gone-bad might cause the car to overheat and cause coolant to overflow from the tank.

Im in the process of ordering a headgasket, new timing belt in the next day or two, but I figured based on what Ive heard regarding the ECU as well as other theories, who knows, maybe someone can give some good info or talk about similiar experiences.

TIA.

Kenny

 

Have you done a compression test? How much boost are you running and on what octane? Head studs ain't gonna help you if you're detonating. It'll only delay the inevitable.

 

what year is your evo?

 

if it's an 03, did you get that recall taken care of for the radiator fan controller module thingy? that caused 03s to overheat.

 

fan controller

pull out the front fuse junction, locate the fan relay and short the top bottom pin of the relay.. if it runs ecu or thermostat kaput.. if it doesn't relay kaput.. relay is a huge 50amp relay next to the front ecu

 

I did a compression test about 2 weeks ago. It was on a cold motor that had warmed to operating temp and stayed there for about 10 minutes.

160 across the board, and there was no signs of coolant on the plugs.

Regarding the recall, my EVO goes in next wednesday, and yep, its an 03.

Kenny

 

^ got the same problem..
thing is my evo is a 2001 E7
never had the problem before and now i do.

let me know what happens and if and how u got it fixed.

and i also did a compression test...perfect results

 

As far as I can tell, its probably the fan controller.. If you turn on your AC to A/C MAX and the fan comes on and stays on, and the car no longer overheats then its definitely the controller..

 

BTW the dead giveaway is you say when your driving it doesnt overheat, but stop and go traffic, thats when the fan cycles on and off.. Thats why I suggested turning on the AC to MAX and see if the fans come on and stay on.. if they do, the car should no longer overheat and its the fan controller..

 

I have a blown head gasket. It does not smoke, I can drive it from here to Mars and back with no problem. When I boost over 21psi the temp guage goes north. If you have headstuds you may have a problem.

 

Jack took the words out of my mouth, my 03 hasn't had this issue, but my Legend did, it was a common problem on those cars as well. Turning on the AC is a sure fire way to diagnose the fan controller problem. Good luck!!

- Steve

 

Interesting that you guys should mention the A/C being used to stop the overheating. When I talked to the service dept guy @ my local Mitsu dealership he said not to use the A/C with the heat turned up when my car overheats because of "parasitic" losses, but to turn off the A/C and turn on the heater at full blast.

But, I find that the overheating seems to cool down quicker with the heat + A/C on rather than just the heat.

Would a faulty fan controller cause coolant to overflow from the tank?

Kenny

 

If your fan never turns on, then your running the engine coolant on it's boiling point. Around 278 F degrees.
Heat causes pressure to rise and the radiator cap can only hold 15-17 psi. Anything above that will open it and coolant will flow to the reservoir tank. Continuos ovreheating will overflow your tank.

Does your fan ever run without turning the AC on ?
Like everyone said. Faulty fan controller would be likely the problem.
Also don't rule out a misreading coolant temp switch. If this sensor isn't giving the right temperature reading to turn your fan on at 190 F degrees, then you'll overheat also.
Turning the AC on bypasses this input.

 

Try having a shop put a pressure gauge on your cooling system and see what pressure it is running...Should be only about 1 bar (14.5psi). This is a common pressure for most cooling systems to run at.

If it is BLOWING coolant out of the overflow, and not BOILING it out of the overflow, that can be an indicator of compression/boost getting in to the cooling system via blown head gasket. Saw this quite a bit with the E36 M3's...always a dead give-away of blown head gasket on those cars.

 

i had the exact same problem

I had a blown headgasket on 3 of 4 cylinders.
This is definately a blown HG

My car had no oil/water mixing, pressure test 180 across, coolant pressure test fine, no rust on plugs, no smoke and when i hit over 21 psi, coolant would overflow. At one point the temp guage sky rocketed