Blowing out antifreeze
 

I have a built 2.0 and am running around 28 psi on e-85. When I hit boost I have noticed that it blows the antifreeze out the overflow. It is not overheating and there is no antifreeze in the oil. It is not burning any antifreeze either. I have arp headstuds and a Commetic metal head gasket all torqued down. Is the coolant cap pressure not high enough or what would be causing this?

Re: Blowing out antifreeze
 

I would try a different cap and see if that makes a difference.

Re: Blowing out antifreeze
 

Sounds like a blown headgasket possible. You are pressurizing the coolant system, most likely.

Re: Blowing out antifreeze
 

Sounds like a blown HG. Was the block decked?

Re: Blowing out antifreeze
 

No it is not. When I brought it in to dyno it early in the year they overheated it on the dyno and it was boiling antifreeze out. Could that reck the gasket and nothing else. This probleb has just started in the last 2 months. Runs perfect besides under full boost. Can I just get (MLS commetic or mitsu, which is better) gasket and put it on with no problems hoping that it was the gasket or is the head warped maybe? I really dont want to have to take the motor out again. What would you do?

Re: Blowing out antifreeze
 

If it overheated it could have definitely warped the head. I had that happen to a car, then shortly after that a rod bearing went. Mine was more drastic than yours though. I would put a stock headgasket on and see what happens, they have more give in them. You are supposed to have a decked block when going to a MLS gasket.

Re: Blowing out antifreeze
 

Yea, sounds like a somewhat blown headgasket. You can have a barely blown headgasket that only shows itself under boost. I usually doesn't hurt power either, but can cause overheating and eventually fail in a much worse way.

Overheating can warped a head and blow a headgasket, but who knows which came first. Often overheating is caused by a blown headgasket. You might be able to just get the head decked and put in a stock headgasket. It is obviously easier to get the head decked than to pull the block and disassemble it to get it decked.

I had a problem with the 6-bolt motor that I got for my wife's 1G a few years ago. It could run or idle forever and never overheat, but as soon as you tried to do a boosted pull, it will push coolant like crazy. After trying everything and headgaskets, we had to pull the motor and get it decked. It hasn't had any problems with pushing any coolant since then.

Re: Blowing out antifreeze
 

Lets pull the head! And then make your engine bay pretty at the same time, especially that sexy red intake manifold.

Re: Blowing out antifreeze
 

Would that show up in a leakdown test?

Re: Blowing out antifreeze
 

bad headgasket, warped block/head, or bad t-stat housing cap. the end

Re: Blowing out antifreeze
 

When was the last time you retorqued them?

Re: Blowing out antifreeze
 

I dont think so, I think thats mainly tests for bad rings or bad valve seats, someone correct me if I am wrong.

Definately sounds like a tweaked headgasket to me.

Re: Blowing out antifreeze
 

Pop off the RAD cap and if there is bubbles during a leakdown test its caused by a bad HG. I know that a blown one would but would a blown headgasket like they are saying show it?

Re: Blowing out antifreeze
 

A small leak, like this seems to be, does not always show up. Yank the head and check it out. Might as well replace the radiator cap first though, for the heck of it.

Re: Blowing out antifreeze
 

If it only leaks under boost the ~100psi you put in there on a leakdown test will not show a blown head gasket.

~John

Re: Blowing out antifreeze
 

johns right, considering the stock motor makes 135 psi in the cylinders, that wouldnt work, but back to the part about the studs, did you ever retorque them????? and have you tried putting a little oil in the cylinder and done a compression check to see if you even get 135 psi per cylinder?!?

Re: Blowing out antifreeze
 

I thought stock was 160 and the service limit is 130??

Re: Blowing out antifreeze
 

That oil thing doesnt work. Because our pistons have a dish in them all you are doing is filling up the piston with oil giving you a little bit higher number.

Re: Blowing out antifreeze
 

Under boosted combustion you might have 1000-2000psi of pressure in the cylinder, so often a simple compression test or leakdown test doesn't show anything for a headgasket that only leaks under boost.