too much pressure

[Epixinc]

kay i have a problem which i cant seem to find a solution for!!!

bought a 91 Talon TSi FWD off a buddy non running. it blew the timing belt on the highway and bent almost every valve!
so i pulled the head and replaced it with a rebuilt. had it decked and put a 3layer MLS head gasket on it. she started right up after i got it all back together. About 3 weeks later i found a way to turn up the boost to 14psi and did it! Three days later she began overheating. I figured it was the thermostat not opening, so i pulled it out the car and continued on. It then blew the lower coolant hose that runs from the oil cooler to the turbo. I replaced it and drove home and she was fine. She didnt overheat until i was sitting in idle. I got a new TSTAT(180degree) and put it in, and it runs real funny...... i drive it and the temp goes up a little past 3/4, then it drops down to a little below midline like the tstat opened up or something..... then as i drive it and boost, it begins heating up to the red line, at which time i pull over and let it cool down. I run the fans at all times, so thats not it. All my hoses have been replaced. My heater core has been elimated, and i am using a stock radiator.

The main thing that worries me is the fact there is so much pressure in the tstat housing. As soon as i start the car, it just shoots out of the housing!!! Kinda like i got a blown headgasket, but i have no other symptoms of that. No mixing, no loss of compression (150 across all four), no smell of burnt antifreeze in the exhaust. Nothing but the high pressures!

So today i took the car over to the shop and tore into her. I removed the head, checked out the headgasket, it looks perfect, paint is a little peeling from it, but it doesnt have any breaks in any of the three layers, and the metal is solid. I checked both the head surface and the block surface with a straight edge and it seems perfect, no warping or nothing. i cleaned both surfaces thoroughly with an air tool, and also cleaned the piston faces!! OH SO SHINY!!! I put it all back together and filled it all up.

Cant really run the car with the cap off, it just pours out!! So i fill it and squeeze the hoses trying to push all the air out! But as soon as i start it, i can open the little safety valve on the rad cap and the fluid just starts pouring into the overflow tank.

When it does overheat, and i pull over it just pumps steam out the overflow hose and when i hit the throttle while it does that the steam is PURE WHITE! Its like its vaporizing the coolant in the compression chamber, but i have no burnt antifreeze in there.

Does anyone have any ideas? someone please help me why do i have so much pressure in the housing. oh and as a side note, if i disconnect the wastegate from the o2housing lever, it does not overheat. so it only overheats under boost..... HELP!

 

[silver bullit]

Learn how to use proper grammer, paragraphs and sentences that start with capital letters.

What you wrote about is so hard to understand its almost not even worth reading it.

What mods are done to the car? Boost gauge other then stock?

Did you check the walls in the cylinders to make sure they where not messed up?

Have you done a compression test (correctly)?

Did the surface of the head and block both feeler gaged? Was the block and head surface clean. Just metal like mirror surface?

Maybe you turbo is shot, from lack of mods or over boosting or using the stock boost gauge.

Check the in and shaft play on the turbo and the side to side motion of it.

Sounds like you need to do the compression test (correctly) and check the turbo like i said above.

 

[kanderson]

It is really hard to read something that long, paragraphs are your friend!

 

[ekanddsm]

I recently did a head on a turbo'd car that would over-pressure the cooling system when driving.

The cooling system had normal pressure untill you boosted and then the cooling system would see about 25 psi, on a 18 psi cap. It would push all the coolant out when boosting.

The head was warped, but not in a humungous bow like a traditional warped head.
It had warped .003 between the combustion chamber and the cooling jacket on cyl 3 towards the exhaust.

Since it would seal under vacuum the car didnt run bad but as soon as it would boost, out comes the coolant.

The car only had 3k miles on it.

So ask yourself, How flat is the head?

 

[ekanddsm]

And I went cross eyed trying to read your post.

Its a forum not a text message.

 

[webconnect]

I have a problem which I can't seem to find a solution for! I bought a 91 Talon TSi FWD off a buddy non-running. It blew the timing belt on the highway, and bent almost every valve.

What I did

1. Pulled head and replaced it with a rebuilt one
2. Had the head decked
3. Installed 3 layer MLS head gasket
4. Installed new TSTAT
5. I checked both the head surface and the block surface with a straight edge
6. Cleaned Pistons

The car started right up after I got it all back together. Then about 3 weeks later I found a way to turn up the boost to 14psi (which I did). Then three days later, the car began overheating. I figured it was the thermostat not opening, so i pulled it out the car and continued on.

Then I blew the lower coolant hose that runs from the oil cooler to the turbo. I Replaced it and drove home and the car was fine. It didn't overheat till it was sitting in idle. So I got a new TSTAT(180degree) and put it in, and it runs real funny...... I drove it and the temp goes up a little past 3/4, then it drops down to little below midline like the tstat opened up or something... then as I drive it and boost, it begins to heat up to the red line. When it does that I pull over and let it cool.

I run the fans at all time, so thats not it. All my hoses have been replaced, my heater core has been deleted, and I am using a stock radiator. The main thing that worries me is the fact there is so much pressure in the tstat housing. As soon as I start the car, it just shoots out of the housing! Kinda like i got a blown head gasket, but I have no other symptoms of that.

No mixing, no loss of compression (150 across all four), No smell of burnt antifreeze in the exhaust. Nothing but the high pressures! So today I took the car over to the shop and tore into her.

I removed the head, checked out the head gasket which looks perfect, paint is a little peeling from it, but it doesn't have any breaks in any of the three layers, and the metal is solid. I checked both the head surface and the block surface with a straight edge and it seems perfect, no warping or nothing. I cleaned both surfaces thoroughly with an air tool, and also cleaned the piston faces. Then I put it all back together and filled it all up.

Cant really run the car with the cap off ### it just pours out!! So I filled it and squeezed the hoses trying to push all the air out, but as soon as I start it, I can open the little safety valve on the rad cap and the fluid just starts pouring into the overflow tank. When it does overheat, I pull over and it just pumps steam out the overflow hose. When I hit the throttle while it is doing that the steam is PURE WHITE! Its like its vaporizing the coolant in the compression chamber. But I have no burnt antifreeze in there.

Does anyone have any ideas? Why do I have so much pressure in the housing.

p.s. If I disconnect the wastegate from the o2housing lever, it does not overheat. It only overheats under boost..... HELP!

 

[Epixinc]

Learn how to use proper grammer, paragraphs and sentences that start with capital letters.

What you wrote about is so hard to understand its almost not even worth reading it.

What mods are done to the car? Boost gauge other then stock?

Did you check the walls in the cylinders to make sure they where not messed up?

Have you done a compression test (correctly)?

Did the surface of the head and block both feeler gaged? Was the block and head surface clean. Just metal like mirror surface?

Maybe you turbo is shot, from lack of mods or over boosting or using the stock boost gauge.

Check the in and shaft play on the turbo and the side to side motion of it.

Sounds like you need to do the compression test (correctly) and check the turbo like i said above.

okay i fixed the grammar crap.

no mods except for a K&N and intake piping with APS Bov/Recirc Valve

Aftermarket AutoMeter Boost gauge running into the P line on the Throttle body

the cylinder walls look absolutely perfect. No grooves or dings

Um i didnt know there was a wrong way to do a compression test. You take the spark plugs out and pull the fuel pump fuse. Then u screw the compression tester into the sparkplug well and crank 4-7 times or until the gauge stops moving.

the head was resurfaced and decked to make it flat. the Block was not. i ran a straight edge across both surfaces and a feeler gauge and they are both as flat as can be!!!

How would a blown turbo cause me to overheat or be high pressure? do the cooling jackets in the turbo recieve pressure when its spooling?

no in and out play on the turbo and very minimal side to side.

 

[Epixinc]

I recently did a head on a turbo'd car that would over-pressure the cooling system when driving.

The cooling system had normal pressure untill you boosted and then the cooling system would see about 25 psi, on a 18 psi cap. It would push all the coolant out when boosting.

The head was warped, but not in a humungous bow like a traditional warped head.
It had warped .003 between the combustion chamber and the cooling jacket on cyl 3 towards the exhaust.

Since it would seal under vacuum the car didnt run bad but as soon as it would boost, out comes the coolant.

The car only had 3k miles on it.

So ask yourself, How flat is the head?

well mine does it as soon as the car starts up. so what could cause that?? i can understand the boost thing, that definitly fits my scenario. it doesnt overheat if i disconnect the wastegate arm. As soon as i start boosting however, she warms up!

 

[silver bullit]

okay i fixed the grammar crap.

no mods except for a K&N and intake piping with APS Bov/Recirc Valve

Aftermarket AutoMeter Boost gauge running into the P line on the Throttle body

the cylinder walls look absolutely perfect. No grooves or dings

Um i didnt know there was a wrong way to do a compression test. You take the spark plugs out and pull the fuel pump fuse. Then u screw the compression tester into the sparkplug well and crank 4-7 times or until the gauge stops moving.

the head was resurfaced and decked to make it flat. the Block was not. i ran a straight edge across both surfaces and a feeler gauge and they are both as flat as can be!!!

How would a blown turbo cause me to overheat or be high pressure? do the cooling jackets in the turbo recieve pressure when its spooling?

no in and out play on the turbo and very minimal side to side.

Unplug the radiator cap, take all the plugs out, while holding the car wot, you turn it over for 5-10 sec. Make sure someone is looking into the thermo housing you see bubble, then that a blown hg 99% of the time.

Did you check the block with a feeler gauge max is supposed to be is .008, with no greater .004? different. Id have to check the book.

Was the head checked in several places to be sure, as the head? There are a total of 9 places the straight edge goes and you have to check the whole length of the head block.

The turbos seals could be failed or cracked allowing air from the exhaust to enter the cooling jacket in the turbo.

Do you have any pre-turbo exhaust leaks?

 

[Epixinc]

i physically looked at the headgasket and it looks almost exactly the same as the day i bought it..... 2 months ago. the only change is some of the paint is peeling off around the cylinder holes.

i dont know what the feeler gauge was showing, but after what the guy said earlier about a warped head, i might just pull it back off and take it to a machine shop.

so if the turbo is blown just a little bit, and the air is pushing into the cooling jackets in the turbo, that could be the cause of the incredible pressure i am dealing with in the thermostat housing? ? ?

 

[Epixinc]

anyone else know why i would have all this pressure in the thermostat housing? ? ?

 

[dcjackson22]

you need to presure test the cooling system. you can buy one from snapon, matco, or even auto zone. try that

 

[Epixinc]

you need to presure test the cooling system. you can buy one from snapon, matco, or even auto zone. try that

for what purpose. i know there is increased pressure in the cooling system, but if say it is the head, how would i possibly get it to push the coolant out of the water jackets? ? if it only overheats under boost, and anytime the car is running it pushes coolant around?