I was driving on the highway last night when I thought I’d do a few quick 3rd and 4th gear pulls in my car…

First pull felt great, I think the car was hitting 15psi... but then, on 3 subsequent pulls something odd was happening, my car would get into boost but I was feeling a lot of hesitation while I was on the throttle, never felt this before in my car… out of boost the car felt fine, in 2nd gear at 70% throttle the car was fine in boost, but the second I see boost in 3rd or 4th gear the car starts having some hard hesitation.

When I get to my buddies house I open the hood and see coolant sprayed along the passenger side of the engine/bay… Did I just lift the heads or blow a head gasket?

After 30 minutes I drove the car home and everything seemed fine, never got back into boost though.

My car is a 2004 6MT G35 coupe, Wiseco pistons, Brian Crower rods, PowerLab GT35R, ProEFI 48 computer, CJM stage 1 RFS, and the car’s running E85. On 15 psi I'm making about 550whp.

 

Check you motor oil.

Most of the time if you have a blown head gasket you will get coolant in the crankcase and when it mixes with the motor oil it turns milky looking.

There are other test too, but this is quick and easy and if you have milky oil you have a blown head gasket for sure.

 

Sounds like a head gasket. Checking the oil sounds like a good idea. What head gasket and what head studs were used?

Could be other reasons for overheating and spraying coolant though...

 

Thanks for the input guys... I pulled the oil dip stick and everything looked normal; going to try to look for any potential coolant leaks next...

I have APR 2000 head studs and HR Z head gaskets on my car too.

Actually Raj, the car never overheated (based on the OEM temperature gauge), when I was logging I stayed out of boost just so I could make it home in one piece. During the 12 mile drive home I saw an average coolant temp of about 199-200 degrees.

Just checked the radiator, it seemed low on coolant so I poured some water in, took about half a gallon to fill it to the top.

 

you should have a coolant temp fault setup. minus a leak, you were pushing water, either from the overflow tank or elsewhere.

dont suppose you have a radiator pressure sensor? I put on on my car for just that reason, to watch for any potential issues.

 

Yeah, unfortunately I don't a radiator pressure sensor, I think my 48's maxed out. Thoughts on what may have caused me to push water and any potential fix?

Thanks guys!

 

Would it be too hard to just drain your oil and see what comes out?

Or is there some reason you haven't done this already.... Like that would answer the question pretty clearly.

 

How much torque is on the head studs?

Sounds like headlift to me. There doesnt have to be any coolant in the oil for this type of leak, and I doubt there will be any. Cylinder pressure passes through the deck to the cooling system... there is no reason for oil to be involved in the transfer.

 

I think they were torqued down to 80 lbs.... I've got about 11k miles on this motor, 3k miles since I installed the fuel system & flex fuel system and bumped the boost up to 15 psi.

 

Maybe you got a hot spot and the gasket burned at that point or something

Sucks.

 

Going to take the car to Intense later today to do a leak-down & compression test, and look for any leaks, etc.

Got another dumb question though, if everything checks out OK would Evans water-less coolant help stop the engine from pushing coolant?

Thanks again everyone!

 

A leakdown and compression test wont show anything for head lift. Pretty much the only symptom you will get from head lift is pressurizing the cooling system at full throttle, and water blasting into the overflow. The leak only occurs during "head lift" which happens at full throttle.

Sooner or later, eventually I would expect it to grow into just a blown headgasket that leaks all the time and displays the normal symptoms.

It doesnt matter what you fill the cooling system with if you are getting head lift, its only going to change what type of coolant blasts into the overflow.

So hopefully its not head lift. But if a top'd off and bled cooling system blasts water into the overflow any time you floor it, thats head lift.

 

There is a small little test kit that will show if any combustion gases are in the coolant. This is a definitive test for a head gasket leak (head lift). You can buy this kit at an auto parts shop, or if going to a repair shop they will (should) have a kit to use.

 

^^^ what Jen said, get a Block Test kit, which will show if there's combustion gas in the cooling system.

 

Evans NPG might help prevent a recurrence though...

 

how do ya figure?

 

Ended up doing the block test last night, results were negative... head gaskets are fine. Still think I'll be switching to Evans water-less coolant and backing off the boost a bit.

 

If a hot spot (air pocket) caused the head gasket to fail focally, the Evans might prevent the 2nd head gasket from failing due to a similar condition.

I suspect the current head gasket will get worse over time regardless if the coolant is switched out now (sorry if that was unclear). This exact same series of events I believe happened to Alberto a couple years back.

 

Got it, and agreed.

I lost to headlift when I did my first build in 04 or 05. But it was a double whammy - sleeved block and standard ARP studs torqued to the ultra low ARP spec. I believe it was right off the dyno that I started to get head lift. I dealt with it for a couple months but it got old real quick.

Swapped to a stock sleeve block with 1/2" studs torqued to around 95-100 and to this day that engine is still running strong.

 

I think there is one other possibility. You will see similar symptoms of head lift with a bad gasket at the cylinder head coolant return pipe? It can draw air into the coolant system, get an air pocket behind the thermostat and then overheat and spew.