Just filled my car up, immediately had to go up a long steep hill (car was already up to temp though). When halfway through the hill I see some steam coming from under the hood. Check the temp gauge and it was off the chart high (never had anything like this happen to it before so I wasn't keeping my eye on it.). Anyway I immediately pull over, and as I do that the radiator goes and spits coolant+ steam all over the car. Looking at it it doesn't look like any was coming out of the head gasket. So what do you think happened / what are my options?

Mods: mishimoto radiator, intake, tbe, ic piping+ ic,fuel pump+ injectors tuned at 24 psi on 91 currently. 320 hp. Stock block stock 8 turbo.

 

You cannot see coolant coming out of the headgasket. Its internal in the cylinders.

 

does the car still start and all? maybe its just a bad thermostat?

 

Haven't tried to restart the car yet, waiting for it to completely cool off/get towed but I'm also hoping its the thermostat, I have my doubts though. Radiators only about 3000 mi old. Could that affect anything?

 

no that wouldnt affect anything.

 

Well the car started just fine, when i pulled to move it, to put it on a trailer a nice little plume of whiteish/blue smoke came out. So whats next? I'm going to pull/ replace the thermostat, but should I also do a compression test?

 

Do a leaksown test. That will be the best way to understand what's going on.

 

I don't know why everyone thinks they killed there motor Everytime something goes wrong. Wait until its cooled off fill it up with fluid and start it up and begin checking. Leaks? Fans work ? Thermostat ? If all that works then start worrying about head gaskets and such.

 

check your oil!! hope its not milky looking.

 

Was the radiator low? Also, u need to pull the oil fill cap off and look into the valve cover. Does it look like a milkshake in there? If so, u popped the head gasket.

 

The most common way a head gasket goes is the head lifts, combustion gases go into the cooling jacket over-pressurizing it, coolant is pushed into the reservoir, and when it fills, onto the ground.

Install a new thermostat and make sure the cooling system is 100%. Then, if it happens again when pulling hard, start thinking head gasket.

 

^ This.
Last time all my coolant came out and temp went through the roof, it was that little hose that connects from the head to the throttle body.

 

sounds like something dumb happened, like a coolant hose came off or something. def not a blown engine.

 

Well using the description from earlier, it does look like a milkshake inside my valve cover. Probably doing a leakdown test tommorow, and maybe pulling the head, we'll see.

 

If its a milkshake inside your valve cover you don't need to do a leak down test. You have a blown head gasket. Period.

Just get the cylinder head off and now you need to figure out what caused it.