i have a 2003 evo 8 with a built 2.3 stroker gt35r. everytime i hit boost, water shoots out of the coolant reservior tank.

i thought i had a warped head, but i sent it out and got it resurfaced. i've changed the radiator cap. with a new head gasket and studs i have the same problem. my next guess is that the block needs to be decked.

any suggestions as to what the problem is?

 

Do a compression test with the radiator cap off, if you see bubbles coming out of the radiator you have a blown HG. But you said you already checked that. Is there any abnormal smoke coming out of the tailpipe?

 

Itcould be a cracked head, cracked block or a cracked throtle body. was the head tested for cracks when it was machined?

 

what kind of head gasket are you using

 

originally i did think i had a blown hg. i pressure tested the cooling system and water leaked into the number 1 and 2 cylinders. but no abnormal smoke except for a little rich condition.

so far, i've ruled out hg, warped head, cracked head.

 

cometic headgasket

 

i've tried cometic, but this time i decided to go with the factory hg. i think if i had a cracked block there would be bigger issues than just water shooting out of the coolant reservior tank. at night or when the air is cool coolant doesn't shoot out and the car doesn't heat up. when it's hot out, coolant shoots out of the reservior tank (really, it literally shoots out!). the engine only starts to overheat when coolant gets low. therefore, if the cooling system is full of coolant and i go wot on a hot day coolant will shoot out, but will not overheat.

 

Have you torqued the studs to 85 ft-lbs?

 

do you run your engine for any lenght of time? i ask because if you only run for five minutes or so your themostat may not be working. if you ran longer you would see overheating issues.

 

one way or another your leaking compression into the water jackets, thats for sure. Blown headgasket, warped head, maybe block needs to be decked?

 

like someone above said, do a leakdown and see if theres bubbles in the coolant. what i do is just hook my air compressor up to the end of my compression tester and compress air into the cylinder. if its leaking out somewhere you will be able to tell easily.

 

I have had the same problem but not on my EVO. I had it on my BMW

Under high rpm and massive piston pressure the piston combustion chamber will pressurized the coolant system little by little until coolant shoots out and in the end you will blow a coolant hose or radiator cap under extreme pressure.

Compression and leak down test won’t help because you are not running the car under massive high pressure when running these tests (you are just cranking the engine, low RPM).

The test you need to run is to check your coolant for exhaust gases (I can’t remember the name of the tool). The tool will simply give you different color if the coolant had exhaust gas in it and that will point you in the right direction.

The coolant system only gets to 15~20 psi when your combustion chamber gets to ~300 psi and the pressure is just transferring. That explains why under no load and no boost you have no problems.

Simply The solution for my car was a fresh new gasket but it could be the head the block (most likely not) or the head gasket.

Also, the bubbles in the coolant won’t show when running a compression check because you are not building enough pressure in the combustion chamber at that level of RPM


hope that helped

 

I had the same symptoms on a previous turbo car. Turned out to be a bad headgasket. If you haven't done a leakdown test then that should be your next move.

 

Sounds like either head lift, warped head, bad headgasket/studs or improper decking of the block when being rebuilt.

Since you said you had the head resurfaced as well as the headgasket, I'd check to see if your studs are in spec/stretched. If the problem still occurs after having the block redecked, it would have to be a crack in the block leading into one of the coolant passages.

 

I've got your exact setup with the stroker and the same problem lies for me with water shooting out through the radiator overflow at 32 psi and gets worse at 35 psi. There's no overheating at all when you drive the car. THe problem is that the head is lifting on boost. Am running a HKS gasket now and I was thinking of replacing the headgasket and re torqueing the head but if the block surface is slightly warped, I'm in trouble too... gotta deck both...