Over heating under boost.

[Kristopher]

higher pressures raise the boiling point  the point of pressurized cooling systems 

Right thought but I wrote the opposite...some form of dyslexia I'm sure..
thanks for catching that!

[Ryan Singh]

So I replaced the rad cap last night, and it's still running pretty hot. Hasn't boiled over yet, but I'm hoping to solve this before it gets to that.
The fan does come on, but it seems as if it comes on late...when the needle's about 3/4 the way up.

I'll go check for exhaust leaks tonight, but with my luck, it's not gonna be that simple a solution.

[Ryan Dronsfield]

Thanks Kris...sorry for thread jackin' Rich, but they're both similar issues so I figured why not. lol

So I replaced the thermostat and did the coolant, was fine for a while (30 min of driving) but now it's running hot again. Not under any load even, just sitting at a light it gets close to red.
Gonna replace the rad cap next...hopefully it's not the water pump dying.  

One thing I didn't do was disconnect the neg terminal before doing it. Would I really have to reset before doing it? You think if I reset, the issue will settle itself?
Because right now, it's running based on how the old thermostat was functioning...right? Or.....

Idling is bad for your care so if you are siting in traffic or a red light if your rad fans arnt working they wont move air over the rad witch may cause it to over heat wail idling but not wile driving the sensors on the thermostat housing of the 2g are as cheep as the thermostat so it wouldn't hurt to replace them
also i had some major issue with my cooling and fuel system it sounded normal and when i hucked up a computer to it it didnt mater what computer i used the car would not talk to the other computers becaus there were somany erorrs i decided to replace the ecu and it fixed 90 percent of my problems however it idnt fix my rad fans but it still runs about 100x cooler
not saying your ecu is broken but if you haven't check for error cods yet it could be a place to check because your ecu controls a large part of your cooling system

[Ryan Dronsfield]

So I replaced the rad cap last night, and it's still running pretty hot. Hasn't boiled over yet, but I'm hoping to solve this before it gets to that.
The fan does come on, but it seems as if it comes on late...when the needle's about 3/4 the way up.

I'll go check for exhaust leaks tonight, but with my luck, it's not gonna be that simple a solution.

check the relays there i think 4 controlling the rad fans one of the speed setting on the fan might not be coming it sounds as if there's only one peed coming on if not that check the ecu for code errors

[John Hartman]

Repeated operation of the engine over the half way mark is bad.  Even a couple of times.  The gauge is not linear.  A needles thickness is lots once the needle is pase half way.  3/4 or more is really hot.

I do wish you good luck, but I am going to say that you have probably cooked the head gasket or slightly warped the head. 

Find the root cause on this tho.  If you fix the rad, or fans, or even the head, but the water pump impeller is not pushing enough water, its gonna happen again.  Not saying thats the exact cause, because this is the interwebz, and I don't have the car in front of me, but its a good example of what I mean.

[Ryan Singh]

Thanks for the replies guys...yeah I know it's bad for the car, but I need to get to work and back. I can't keep pulling over all the time either. It's not as bad as I may have made it out to seem. I live in South Surrey, and drive to Kitsilano everyday...about 45min-1hr drive. It only starts getting hot when I'm like 10 min away from work...and even then, I don't really have to turn on the heat.

That all said, I did replace the thermostat and rap cap...and will keep replacing shit till it's fixed. A new water pump is well overdue...as is the T-belt..so I'm thinking to just have them both done anyway.

But I'm trying to figure it out without having to drop $800 on it. So I guess I keep checking sensors and other small shit.

So how many speed settings are there on the fan?

[John Hartman]

1.  Its on or off on these cars.  Some newer ones have plusewidth modulated motors, so they can speed up and slow down the fan, but still at the end of the day, the motor itself is a 1 speed. 

[patrickWoo]

Simpler steps: start with squeezing the upper rad hose immediately after a short run at operating temperature. It should feel like it has a boner - like a raging boner not a 50 y/o limp dick. If that's true, it might be just your exhaust leak hitting the sensor. The water pump rarely fails on these engines so I wouldn't count on it, the stiff upper rad hose is a good indication that the system is holding pressure AND that the system is recirculating - but not a good indication of how well the recirculation is being carried out.

if the rad hose has no boner in it, then:
rad cap - check for leaks in unsightly places - tstat

in that order.

1. Logic is that a faulty rad cap fails to pull in coolant from reservoir tank. So you have a big portion of the radiator holding air and not cooling anything properly.
2. A leaky system will always hover at 100C or thereabouts and if you boost it'll just rapidly build heat. The heating system on a Lancer EVO does not have a valve the system ALWAYS go through the in-car heater core and you could be leaking inside the car without knowing it. The carpet (that exists on a Galant, not sure about the EVO) on the firewall absorbs up all the leak from the heater core hose making a leak trace around that area difficult as well (the indication is that if you peek under the car immediately after you park it does not drip, but if you leave it for hours there will be a puddle on the ground anyway).
3. If you have good rad cap and no leaks then it still comes back to T-stat. T-stat could be partially stuck causing an inadequate flow of coolant. A really stuck t-stat also limits your cooling to the upper row of the radiator, causing overheating only in selected circumstances. Best economical way to test this is to remove the t-stat altogether. If the car no longer overheats then that's your problem right there. 

Of course you probably can find a pressure tester before you run through all of these tests, but these tests can be done without any shop tools so why not.

having exhaust escape into the cooling system has really dramatic effect especially if you put boost into it.....so I wouldn't even consider that possibility yet. Plus an engine that makes 175psi across is perfectly healthy.

[Jason Harwood]

FYI - you should squeeze it and if it is HOT and the lower hose is HOT you know the coolant flow is good and the thermostat is OPEN.

That's the test, not a raging boner test, which is the stupidest thing ive heard since the time you sold a cressida to my friend and left your glasses in it.

Simpler steps: start with squeezing the upper rad hose immediately after a short run at operating temperature. It should feel like it has a boner - like a raging boner not a 50 y/o limp dick. If that's true, it might be just your exhaust leak hitting the sensor. The water pump rarely fails on these engines so I wouldn't count on it, the stiff upper rad hose is a good indication that the system is holding pressure AND that the system is recirculating - but not a good indication of how well the recirculation is being carried out.

if the rad hose has no boner in it, then:
rad cap - check for leaks in unsightly places - tstat

in that order.

1. Logic is that a faulty rad cap fails to pull in coolant from reservoir tank. So you have a big portion of the radiator holding air and not cooling anything properly.
2. A leaky system will always hover at 100C or thereabouts and if you boost it'll just rapidly build heat. The heating system on a Lancer EVO does not have a valve the system ALWAYS go through the in-car heater core and you could be leaking inside the car without knowing it. The carpet (that exists on a Galant, not sure about the EVO) on the firewall absorbs up all the leak from the heater core hose making a leak trace around that area difficult as well (the indication is that if you peek under the car immediately after you park it does not drip, but if you leave it for hours there will be a puddle on the ground anyway).
3. If you have good rad cap and no leaks then it still comes back to T-stat. T-stat could be partially stuck causing an inadequate flow of coolant. A really stuck t-stat also limits your cooling to the upper row of the radiator, causing overheating only in selected circumstances. Best economical way to test this is to remove the t-stat altogether. If the car no longer overheats then that's your problem right there. 

Of course you probably can find a pressure tester before you run through all of these tests, but these tests can be done without any shop tools so why not.

having exhaust escape into the cooling system has really dramatic effect especially if you put boost into it.....so I wouldn't even consider that possibility yet. Plus an engine that makes 175psi across is perfectly healthy.

[Jason Harwood]

So I replaced the rad cap last night, and it's still running pretty hot. Hasn't boiled over yet, but I'm hoping to solve this before it gets to that.
The fan does come on, but it seems as if it comes on late...when the needle's about 3/4 the way up.

I'll go check for exhaust leaks tonight, but with my luck, it's not gonna be that simple a solution.

Do my test of the upper and lower rad hoses for after it reach's operating temp's.
If theyre both hot, your thermostat is working and the coolant flow is good.
You can always run sans thermostat and let it stay colder all the time.

[Richard Clark]

Simpler steps: start with squeezing the upper rad hose immediately after a short run at operating temperature. It should feel like it has a boner - like a raging boner not a 50 y/o limp dick. If that's true, it might be just your exhaust leak hitting the sensor. The water pump rarely fails on these engines so I wouldn't count on it, the stiff upper rad hose is a good indication that the system is holding pressure AND that the system is recirculating - but not a good indication of how well the recirculation is being carried out.

if the rad hose has no boner in it, then:
rad cap - check for leaks in unsightly places - tstat

in that order.

1. Logic is that a faulty rad cap fails to pull in coolant from reservoir tank. So you have a big portion of the radiator holding air and not cooling anything properly.
2. A leaky system will always hover at 100C or thereabouts and if you boost it'll just rapidly build heat. The heating system on a Lancer EVO does not have a valve the system ALWAYS go through the in-car heater core and you could be leaking inside the car without knowing it. The carpet (that exists on a Galant, not sure about the EVO) on the firewall absorbs up all the leak from the heater core hose making a leak trace around that area difficult as well (the indication is that if you peek under the car immediately after you park it does not drip, but if you leave it for hours there will be a puddle on the ground anyway).
3. If you have good rad cap and no leaks then it still comes back to T-stat. T-stat could be partially stuck causing an inadequate flow of coolant. A really stuck t-stat also limits your cooling to the upper row of the radiator, causing overheating only in selected circumstances. Best economical way to test this is to remove the t-stat altogether. If the car no longer overheats then that's your problem right there. 

Of course you probably can find a pressure tester before you run through all of these tests, but these tests can be done without any shop tools so why not.

having exhaust escape into the cooling system has really dramatic effect especially if you put boost into it.....so I wouldn't even consider that possibility yet. Plus an engine that makes 175psi across is perfectly healthy.

Both rad hoses felt like normal operating temp, the coolant in the rad felt like normal operating temp.   I thought it could be the tstat right away but considered the worst. A comp test wont always tell you everything which is why i considered that it could be lifting under boost.  My overflow was dry yesterday. I'm gonna do a leakdown on it.  It is off the rd now to redo the intercooler piping and swap the turbo's, fix this OH issue, and do the timing.

I will figure it out.

[Kimyee Lai]

It should feel like it has a boner - like a raging boner not a 50 y/o limp dick.

Maybe you know, but I have absolutely no idea what a 50 y/o limp dick feels like...

[John Hartman]

not only that, and what Jason said, but you can have HUGE pressure in your rad hoses if you have an air pocket and its boiling making steam.

[Paul Davis]

If the rad fan is coming on but when the engine is already too hot, maybe the fan temperature sensor is out of whack.  This sensor screws into the rad.
Mine failed completely a few years ago causing the fan to stop coming on.

[Brett Haviland]

just screw it rich and sell the car to me for 1 Gnote