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2007 STI Silver
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9 Posts
Discussion Starter #1
I have a 2007 STI that I have replace the radiator, thermostat, both radiator caps, the water pump, and the timing belt. You can fill the car with water or coolant and it will idle all day at running temp but after you drive the car for no longer than 5 minutes it blows the coolant out of the overflow, then with the radiator cap off it just shoots water out the top and gurgles out. Oil is not going anywhere and there is no water in the oil. There are no visible leaks and I am just at a loss of where to go from here.
 

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Turbo, LS swapped Impreza RS
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5,172 Posts
Did you burp it?
 

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2007 STI Silver
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9 Posts
Discussion Starter #4
Yes I burped it and I use the funnel kit. The fans kick on when they are supposed to. I have not felt the lower house but in the top house while I was burping it you could feel the air. Its hard to burp it because you cant keep water in it, it will shoot out of the radiator and the upper filler.
 

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2007 STI Silver
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9 Posts
Discussion Starter #5
I did get it to stop shooting out and flow like it is supposed to, so I tried to drive it around and see what it would do. It made it about 3 miles then I gave it some gas and instantly the temp shot up and I had to baby it back home turn it off let it cool off then finish the drive back. After it did this we could not get it to flow right again it just keeps taking water shooting it out then repeat.
 

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2007 STI Silver
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9 Posts
Discussion Starter #7
Well before I drained all the water for winter I had the car where it wouldnt overheat and coolant didnt go away that much. I was running straight water so I dont know if it was just water boiling off or it actually is a bad HG.
 

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I kill threads!
2000 Ver 6 STI - 1996 Gravel Express
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3,749 Posts
I'd probably just flush out the system. Last time I gave it a really good flushing. Pulled the radiator off and hooked up a garden hose to it. Did the same thing with the engine. Then slap everything back together and burped the system. Don't forget to run your heater when burping it.
 

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needs more cowbell
95L, 07 2.5i, R6
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9,315 Posts
If its an sti just let the car run / idle for ten minutes or so at normal operating temp continuing to keep the expansion tank on the engine full. Don't fill it anywhere else, that is the highest point where the air will rise to. After its been running for ten minutes at normal temperature, let it cool down for about thirty minutes. Be sure to add coolant to the expansion tank as its contracting, don't worry about putting the cap on yet. After about thirty minutes put the cap back on. Now run / idle it again at normal temp for 10 to 15 minutes making sure the reservoir / overflow is completely full before you begin. After running those 10 to 15 minutes let it cool down again for about 30. If you completely fill the overflow / reservoir to the very top, it will have enough to compensate for any air bubbles in the system so that every time you drive then it cools down it will blow the bubbles out then draw in coolant with no air. If you've changed all of the parts you say you have and it still continues to blow out, its possible you have a headgasket issue.
 

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2007 STI Silver
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9 Posts
Discussion Starter #10
Well the radiator is pretty well brand new but the motor probably could use that, pretty sure the guy before me ran straight water in it.
 

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needs more cowbell
95L, 07 2.5i, R6
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9,315 Posts
Water really isn't bad for temporary use, it just freezes at a higher temperature than coolant. Water also can corrode passages over time but it usually takes a while and its likely that car hasn't used pure water most of its life.
 

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2007 STI Silver
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Discussion Starter #12
If its an sti just let the car run / idle for ten minutes or so at normal operating temp continuing to keep the expansion tank on the engine full. Don't fill it anywhere else, that is the highest point where the air will rise to. After its been running for ten minutes at normal temperature, let it cool down for about thirty minutes. Be sure to add coolant to the expansion tank as its contracting, don't worry about putting the cap on yet. After about thirty minutes put the cap back on. Now run / idle it again at normal temp for 10 to 15 minutes making sure the reservoir / overflow is completely full before you begin. After running those 10 to 15 minutes let it cool down again for about 30. If you completely fill the overflow / reservoir to the very top, it will have enough to compensate for any air bubbles in the system so that every time you drive then it cools down it will blow the bubbles out then draw in coolant with no air. If you've changed all of the parts you say you have and it still continues to blow out, its possible you have a headgasket issue.
I pretty well did this put about 4 gallons of water in it probably more it just spits it all out the top then its low you fill it again then it spits it out again. I am going to run a garden house through the motor and radiator tomorrow and try and flush it out I know it has rust and crud in the system and maybe its just clogged
 

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2007 STI Silver
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Discussion Starter #13
Water really isn't bad for temporary use, it just freezes at a higher temperature than coolant. Water also can corrode passages over time but it usually takes a while and its likely that car hasn't used pure water most of its life.
When I pulled the water pump off there was a bunch of rust and dirt on the block itself
 

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2001 Coupe
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1,261 Posts
Needs a good flush then as the heat isn't transferring out of the block through the corrosion.

I'd personally do a vinegar flush followed by lots of distilled water. Try swapping the heater hoses top to bottom to backflush the core too.
 
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