Possible head gasket?
 

So I was at thunderhill this weekend and my sti started to push coolant out off the radiator into the overflow. After my first session I notice the overflow being full so I emptied and put water In the radiator then right after my second session I check and the radiator was missing a bunch off coolant, that was all in the overflow. I kept doing thAt all day till the end when I started comming out off the top off the overflow, I kept my eyes on the temp gauge and it never went over 190f. I think it's possibly a head gasket, has anybody had this happend to them, any ideas?

Thanks, silvio

I have had similar issues at the track in the past.

If the coolant doesn't have oil film in it, or pumping all water out and overheating, probably not the gasket.

Check both the radiator caps and how they seal and the hoses to the overflow for leaks. The cooling system can't draw back if there is any air leak at/after the caps.

The caps might be leaking coise I could hear air leaking out of one off the caps, but I was coming out of the cooling how would the air get and and pressurized enough to push most off the coolant out of the radiator, but am going to try to get new caps(easier than headgasket). The other thing I forgot to say is that I drove back with no problems(coolant stayed in radiator).

I've had this problem, same with brent blakely. Mine was a head gasket and water pump issue. i think

But start with the caps, then thermostat,

I ended up just going to a shop and getting the hydrocarbon sniffer test in my coolant overflow and it came right up. :|

so am flushing my cooling system and replacing thermostat and radiator caps. I am about to buy coolant for the car and i have a few options i thout i post them here see what you guys think?

1) Evans waterless coolant
http://www.hrpworld.com/index.cfm?tp...action=product

2) Normal coolant with redlines waterwetter
http://www.hrpworld.com/index.cfm?tp...action=product

3)Normal coolant

Normal coolant. Water wetter isn't a bad idea.

Normal, distilled water and water wetter would be my suggestion.

I can't recall if Subaru recommends their magic potion additive for the STI.

I've always used OEM coolant and OEM magic potion.

The royal purple equivalent to water wetter (Royal Purple Ice) is better than the redline product, or so I've been told by the Benson Bros who have switched to it in their race cars. I've got the purple stuff in my race car now, though I haven't pushed the car hard at all since it went in so I can't really tell if it's helping or not.

^^ I've heard that same thing, but also have no evidence to back it up...

I'm with these guys. I'd go with 1/2 gallon of OEM coolant, 1 bottle of Water Watter or the RP stuff, and distilled water for the rest of the system volume. AFAIK you don't need the head gasket conditioner in bugeye or later DOHC engines.

Scott, did they mention a specific reason they liked it better? I've read a bit about the chemistry of WW and from what I can tell, it's good at doing what it's supposed to do. Not to say something else can't be better of course.

I don't remember the specifics, but it was more of an issue w/ WW gunking up in the coolant passages more than actual cooling performance or something. The RP stuff is just supposed to be a better conditioner for the system I guess? I really don't remember.

Coolant System FAQ

If you click the link under, "What aftermarket coolant can I use", it will say that all Subaru motors should use the OEM conditioner. So I do that. Not trying to make anyone wrong, just saying...

Pretty sure I saw something in the manuals for my car about it too...

Interesting. Either way I guess it's cheap insurance.

True that. They're about a buck each if you get them online.

Yeah, and in fact, every manufacturer that I've seen says you have to use their coolant, or the world will come to an end. My car hasn't had Subaru coolant in it for the last 6 years, and hasn't had a single problem.

so I was at auto-x yesterday and by the time a did my 6th run of the second half of the day, the car started doing the same thing again(pump coolant into overflow and out the top). the car has new thermostat, fresh coolant, waterwetter, 2 brand new high pressure sti radiator caps, and the subie additive. anybody have any suggestions or ideas?

Might be time for a compression/leakdown test.

Well you are describing EXACTLY what happened to Brent and I.

I'de run out and get a hydrocarbon sniffer test done ASAP and rule out (or rule positive) your head gasket. but I'de bet you $20 that you have a small head gasket leak. Mine was never bad enough to throw a check engine light, Brents was and the code came up "small head gasket leak" neither of us ever got oil into our coolant.

I was able to get my car to push coolant by going WOT up to the speed limit on highway on ramps if i made a loop and hit an onramp about 6 times in a row (~ 8 minutes of driving)

There's just not that many ways to push coolant out , 1) faulty cap , 2) air bubble, 3) over heat, 4) head gasket issues.

i think the subaru speciality place was like $100, nissan or subaru might be cheaper ... ? C&C would probably be a bunch cheaper if they have the sniffer tool

Silvio, mine did this as well. The issue appears to be inability to draw back the fluid on cooling and/or drawing in air/vapor instead.

Hoses, caps, etc...

I did find that having a cap that has one of the pressure relief valves/levers allowed me to purge the vapor and get a vacuum to draw back fluid.

so which caps do you think I should get? I am going to do a compression test today Ill keep you guys posted on the numbers I get.

For the top tank, I got a cheap 18PSI levered one at Kragen or wherever. Again did not solve the problem but permitted me to purge the vapor build up when hot allowing draw back to work correctly. Don't know why though.

Check the seats for the caps as well. DK had one so bad that the radiator had to be swapped.