Coolant gurus, need ideas....

[BoostJunkie]

I searched and found some ideas, just lookin for more.

Loosing coolant through the overflow bottle. It is being forced out in little doses. I saw it do this while the turbo timer was running, heard pressure release and saw a little coolant on the ground under the bottle.

Does not overheat. Oil and coolant not mixed. After long cooldown when I take the cap (1.1bar) off it releases alot of pressure (figure no leaks or air getting in system). Doesnt seem to have BHG symptoms. Oil is still black, yes I need an oil change. Not blowin smoke while driving.

I know I need to do tests, just seein if there might be some stupid little thing that might cause this to happen. I've looked at the hoses and none seem to be leaking.

Note: Owning a 7MGTE Supra should include a medical warning, may cause High Blood pressure and stress. :aigo:

 

[toy fanatic78]

Hate to say it ,but sounds like combustion pressure in your cooling system.

 

[CyFi6]

There actually is one stupid little thing that causes this..3 letters.......::bhg:::biglaugh:

 

[noel]

im sure i dont have bhg ....but.... i do have one of thoses pressure rad. Caps that purges the cooling system ... some times when i raceing up and down i go to purge this baby coolant goes into the overflow bottle is it suposed to do ?

 

[CyFi6]

im sure i dont have bhg ....but.... i do have one of thoses pressure rad. Caps that purges the cooling system ... some times when i raceing up and down i go to purge this baby coolant goes into the overflow bottle is it suposed to do ?

say what now?

 

[BoostJunkie]

oh I see, so not overheating, no smoke, no oil and coolant mix, just pressure release from the overflow and it means I have a BHG.
Please explain

 

[CyFi6]

Precisely the symptoms my BHG had, and many others... A head gasket can, and most commonly has a leak between one or more cylinders and the coolant jacket. In many instances the leak is so small that cooling system pressure (13 psi) is not enough to leak through, but combustion pressure (greatly higher) can push out into the cooling system and create air pockets. Also, when air is being pushed into the cooling system like this, it takes the place of the coolant, and the coolant has to go somewhere = right out the overflow.

Now im not saying that you in fact have a blown head gasket, im saying it is very possible, and if you think otherwise maybe you can do some tests to rule it out first.

And by the way, after a long cool down you should not have any pressure in the system.

 

[noel]

stupid question how do i test to see if i have a bhg without taking the 7mgte apart??

Most of the other auto parts store have thoses pressure purge raditor Caps[mines is 13lbs] When u pull up the red tab, it releases pressure. well when i do it sometimes it's just air, or coolant but very little cuz i can hear it drop into the overflow tank i rarely have to add coolant Rarely ...If I have small coolant leak somewhere would that make pressure in the cooling system...

IF not what does make pressure in the cooling system??

 

[toy fanatic78]

I believe it's the coolant getting hot that creates the pressure,don't quote me on that though.
You can get a test kit at napa(not sure if other parts stores carry them)the kit tests for combustion gases in your coolant,that way you can test w/o disassembly.

 

[CyFi6]

stupid question how do i test to see if i have a bhg without taking the 7mgte apart??

Most of the other auto parts store have thoses pressure purge raditor Caps[mines is 13lbs] When u pull up the red tab, it releases pressure. well when i do it sometimes it's just air, or coolant but very little cuz i can hear it drop into the overflow tank i rarely have to add coolant Rarely ...If I have small coolant leak somewhere would that make pressure in the cooling system...

IF not what does make pressure in the cooling system??

You need that pressure to be there when the engine is hot, don't release it. It helps keep your coolant from boiling.

 

[BoostJunkie]

So if you are sayin that there shouldnt be pressure in the system after cooldown, then why would there still be presure in the system. Why isnt it gone? What would cause it to hold pressure?

I will do the proper test to either confirm or rule out BHG, just tryin to understand more about this.

Damn it why couldnt Toyota just do a recall on the 7M and give everyone a 2JZ!! Cause I sure as hell cant afford the $7000 tag to do the swap. But then again after all the friggin head jobs needed to be done on these cars you probably could of saved up for it. I see a for sale section comin soon!

 

[toy fanatic78]

Maybe a little bit of residual pressure after cool down,but shouldn't be building enough pressure while running to get past the radiator cap,that's the problem I would be concerned about at this time.

 

[noel]

Maybe a little bit of residual pressure after cool down,but shouldn't be building enough pressure while running to get past the radiator cap,that's the problem I would be concerned about at this time.

Ooooo okay i see dammm this whole time i was purgeing the system right after a drive oops now i know to lol ...when the car is cold for there is no pressure ! Thank GOD! Lord Jesus christ! lol im happy ....YOU GUys are a real Help......but i have one more question whats the piont of that raditor purge cap then?? when are u suposed to purge the cooling system???

 

[toy fanatic78]

Ooooo okay i see dammm this whole time i was purgeing the system right after a drive oops now i know to lol ...when the car is cold for there is no pressure ! Thank GOD! Lord Jesus christ! lol im happy ....YOU GUys are a real Help......but i have one more question whats the piont of that raditor purge cap then?? when are u suposed to purge the cooling system???

Those caps are intended to release any residual pressure after the car cools down,it's more of a safeguard to keep from blowing the cap off if you try to remove it while engine is hot.If you lift the tab(or purge)well it's hot this causes a pressure drop in the system,which in turn causes the coolant to expand/boil(.The pressure raises the boiling point of the coolant,higher pressure=higher boiling point)

 

[noel]

Those caps are intended to release any residual pressure after the car cools down,it's more of a safeguard to keep from blowing the cap off if you try to remove it while engine is hot.If you lift the tab(or purge)well it's hot this causes a pressure drop in the system,which in turn causes the coolant to expand/boil(.The pressure raises the boiling point of the coolant,higher pressure=higher boiling point)

well if u have any pressure after the car cools that means you have a bhg?? or another problem right??
i forgot the reason but when you squeeze the top raditor hose after a drive and the hose is tight, is that good ??

 

[toy fanatic78]

well if u have any pressure after the car cools that means you have a bhg?? or another problem right??
i forgot the reason but when you squeeze the top raditor hose after a drive and the hose is tight, is that good ??

Some pressure is normal(a few pounds),even after it cools.Hose will feel tight after a drive as there is ~14 lbs of pressure in it.Sign of bhg is when your coolant is blowing right past your cap(will typically overfill/overflow your overflow tank.)That's from combustion pressure in the cooling system.

 

[noel]

alright great my cap does no boiling what so ever lol! i need to do a leak down test to make sure im not leaking anything...

if i do have a leak somewhere it wouldn't hold 14psi correct??

 

[toy fanatic78]

You mean testing the cooling system right?Not a cylinder leak down test.Hook the pressure tester up to the radiator and start the car,if the HG is leaking combustion gasses it will cause the needle on the tester to fluctuate.If your leaking any where else,you should be able to determine that just by pumping the tester up with the car off,and waiting to see if the pressure drops off.

 

[IJ.]

Most of the test kits I've seen change colour if there's Carbon Monoxide in the coolant, pressure testing is a different thing again.

 

[toy fanatic78]

Most of the test kits I've seen change colour if there's Carbon Monoxide in the coolant, pressure testing is a different thing again.

That's the type of test lit I was referring to in post #9.