Coolant getting pushed out of system

What would make the coolant get pushed out of the system into the overflow bottle? Practically drains the entire system after some hard boosting. Before my new head I ran the car with no thermostat for awhile and it didn't overheat again. However, I put in a brand new thermostat when I put the new head on. I am getting a coolant system flush done this week to see if that fixes it. Any other suggestions?

Well I did some researching and I'm leaning heavily towards a leaky headgasket that holds enough compression at idle and normal driving but under boost it leaks the pressure out into the coolant system causing the excess pressure in the system. I noticed a power loss in the car along with the pushed coolant out of the system. There is also no oil in my coolant or coolant in my oil.

I plan on dropping my car off at extreme motorsports and having them check both the head and the block to make sure everything is flat and smooth. The head should be fine because its brand new but, hopefully the block is fine too. Hopefully they can get a good seal for me. I am getting my radiator pressure tested friday before I go through all this though. I'll update later.

My understanding is that a little coolant overflowing into the tank is normal, that's what it's there for. Unless it is filling up and busting out the top, you should be fine I would think.

How much were you boosting and what head gasket are you using right now? And im sure you did but did you replace the head gasket when you put your head back on?

Yes, a brand new 4 layer metal cometic headgasket went on with the new head. I've only been running 16psi of boost.

I understand the concept of the overflow bottle. The coolant isn't "leaking" its spraying out. The extra pressure in my coolant system is blowing out all the coolant and completely draining my entire coolant system.

I have also noticed a dramtic loss of power now while boosting so im 95% sure its a leaky headgasket leaking the boost into my coolant system.

The MLS gaskets are great, but you have to follow the torque specs perfectly. Otherwise, it'll cost ya..

if you did not have a special surface done to the head and block that head gasket is the wrong one to buy. I did the same thing :( i put a 4 layer metal HG on mine and now i am pushing coolant. I can push all the coolant out of mine within 35 minutes or so depending on how much i am boosting. So since the car has been put up for the winter i am not worring about it till spring. Then i am putting the sce copper HG on with the built in o rings in the gasket around every hole. They claim you will never push coolant with this gasket with no special surface done with also some warpage if you have any.

So my mls 4 layer metal gasket has been on for 3,600 miles and there is a guy here that is going to give $30 for it :) better than nothing i guess lol

EDIT* I have not noticed no power loss, just pushing coolant, search for pushing coolant and you will see all the problems people have with this issue, i have done alot of reading on it in the dsmlink forum.

Haha yeah I read up yesterday. Well wouldn't a loss in power make sense? If your loosing pressure in the cylinder then that means loss of power correct? Expecially if your basically leaking boost into your coolant line. I can drain mine in less than 10 minutes btw lol. My head was BRAND NEW the surface was perfect. However, I do not know about the block. I was too stupid to check it for warpage and what not. This problem came on very slow then got worse within like 1 day of hard boosting. Thats why I'm thinking it has to be the HG and not a coolant system problem aka blockage.

I am pretty much leaning towards letting extreme motorsports do it. I have done 3 head jobs now and I'm sick of it. I called yesterday and they said 800-900 for labor+parts. However, all the parts are brand new and do not need replaced except for a new headgasket. So I should be able to get it for like 600-700 bucks hopefully. I'm thinking about going with a copper gasket too just to be sure I get a good seal.

BTW my cometic 4 layer mls has less than 80 miles on it and its basically trash.

My head was BRAND NEW the surface was perfect

It may have been new, but the surface finish for a standard headgasket is slightly rougher than one prepped for a MLS.

Ah, makes sense. Deffinatly could be another factor. The head was done by a local performance shop but, I do not know what he did about the final finish. I am almost certain I will be going with the titan copper HG with built in o-rings and wire though, just to be sure this time. I'm so sick of HGs I can't even spell them out anymore lol. You know its bad when you start getting really fast at doing timing jobs(last one took just under 3 hours).

heh heh, you outta do that for a living!

Haha yeah I ended up modifying my middle timing cover so I didn't have to take the water pump pully off(saves alot of time). At least you get payed for dealing with the bullcrap. I just get black scraped up hands, some broken tools, and a half ass running car lol.

The metal HG's are very tricky and I seem to find about 50% of the people have problems with them. Most machine shops don't understand how perfect the head and block have to be to correctly support a metal HG. You problem is most likely the fact that you didn't do anything with the block.

Is there a reason that you want to go with the metal HG? I would just stick with the stock gasket and some ARP's. That should support whatever you want to throw at it, unless you are going to do something disgusting. There are a bunch of guys that have proved the ARP / stock HG, can support 30+ psi and well over 500WHP.

Yeah, I would go with a stock gasket but, I just want to be sure so I'm going with a copper. I do have arps btw... so I think I should be alright unless my block is beyond help.

http://www.headgasket.com/preinstall.html

Here's a good site to check out if your planning to use copper