strange pressure in the cooling system

[Andrei]

Hello everyone



I have pressure in the cooling system, the fluid is going to the Coolant Overflow Tank, It will fill up fast and spit the water outside.
I have a brand new koyorad radiator, changed to a new thermostat, even tried a 1.3 bar cap (Check my cap also and its fine).
I was sure that the head gasket is leaking but I did the leak block test (with the blue water) and its fine (doesn't turn yellow)
(the car doesn't overheat, only after it spitting enough water)

now i'm stuck and don't know what to do, I don't want to take down the engine if I'm not sure that is a head gasket failure.



someone have a clue what can it be? or how to check from here

Thanks

[DarkPira7e]

Have you taken it to a shop? I only know of 2 things that cause pressure: expansion from heat, and external pressure from gasket blowby. How are you monitoring the car's temperature to be sure it's not overheating?

[Tcoat]

An overfill can do that . It will eventually level out. Could be air as well but I put my money on overfill.

[DarkPira7e]

Originally Posted by Tcoat

An overfill can do that . It will eventually level out. Could be air as well but I put my money on overfill.

Can't believe I didn't think of this.... Thanks @Tcoat

[RZNT4R]

Originally Posted by Andrei

Hello everyone



I have pressure in the cooling system, the fluid is going to the Coolant Overflow Tank, It will fill up fast and spit the water outside.
I have a brand new koyorad radiator, changed to a new thermostat, even tried a 1.3 bar cap (Check my cap also and its fine).
I was sure that the head gasket is leaking but I did the leak block test (with the blue water) and its fine (doesn't turn yellow)
(the car doesn't overheat, only after it spitting enough water)

now i'm stuck and don't know what to do, I don't want to take down the engine if I'm not sure that is a head gasket failure.



someone have a clue what can it be? or how to check from here

Thanks

Did you bleed it from the bleed screw on the heater elbow? The engine is so low compared to the heater that it won't circulate if you've got an air pocket there, and guess what opens the thermostat.

Yup, the heater bypass.

Unless you've got the overflow filled to the brim, I'd be surprised if this was an overfilled situation. Fill it to the FULL mark on the reservoir and up to the overflow port on the rad. If you've got the classic "Yellow Funnel" to fill up the rad that's OK, bleed it while it runs with the heater bleed screen and the funnel on it. If you can use a vacuum filler that's the best way to go.

[ls1ac]

RZNT4R Is running on the right track. Just to reiterate: A bubble in the engine will expand and push the coolant out. A method called vacuum fill will pull most of the air out and suck coolant in. This is the preferred method on new cars. Usually cycling the engine to temperature about six or 10 times will solve the problem. When you do this have the heater on.


edit: If you did a really poor job of filling there could be air around the thermostat and it will not let the thermostat open. There is a very small bleed hole that is designed to let air pass but it can take some time and the engine will usually get hot.

[Ultramaroon]

^^^this^^^


You're most of the way there. Fill the air gap at the top of the radiator. Bleed the air off of the heater core. Heat cycle the engine again.


Let it cool.
Repeat until you see nothing but coolant under the cap when it's cold.

[Andrei]

I was at 2 good mechanics,
I didn't overfill (the water was between the low and full)
even so the water will keep spitting outside until it be liters missing in the system
I did bleed it from the bleed screw and wait until the car was hot

and I checked the temperature using a special tool of the mechanic that connected to the OBD2 that tells exactly the temperature

[tomm.brz]

this misterious special tool is doing the same thing as a obd reader built with 10cents of components!

And how is the oil temp from obd when the coolant starts to overheat?
did both overheat at idle in the long term?

[RZNT4R]

Oh, also, this is going to sound REALLY stupid...

You've changed your rad... are the shipping plugs out of the inlet and outlet? I once saw a guy get trapped by a shipping plug that was shoved really far in and he just hadn't seen it, result: no coolant circulation.

When its spitting out coolant, what's the radiator core temp? What are the hose temps? What are the fans doing?

[Andrei]

Originally Posted by tomm.brz

this misterious special tool is doing the same thing as a obd reader built with 10cents of components!
And how is the oil temp from obd when the coolant starts to overheat?
did both overheat at idle in the long term?

I tried for two hours on idle and no spitting out coolant, so it doesn't overheat,
oil temperature i didn't check

Originally Posted by RZNT4R

Oh, also, this is going to sound REALLY stupid...
You've changed your rad... are the shipping plugs out of the inlet and outlet? I once saw a guy get trapped by a shipping plug that was shoved really far in and he just hadn't seen it, result: no coolant circulation.
When its spitting out coolant, what's the radiator core temp? What are the hose temps? What are the fans doing?

I definitely takes out the radiator caps
I don't remember exactly, in 91 degrees the first speed fans starts and in 96 degrees the fast speed kicks in
hose temps I didn't check only by hand and after the thermostat open all the hose and the radiator are hot

[ActionMaxon]

Thermostat in backwards?

[RZNT4R]

Originally Posted by Andrei

I don't remember exactly, in 91 degrees the first speed fans starts and in 96 degrees the fast speed kicks in
hose temps I didn't check only by hand and after the thermostat open all the hose and the radiator are hot

So I am to presume that when the fans kick in high, it's blowing out a LOT of VERY HOT air? I've seen low circulating systems where the rad gets hot, but as soon as the fans kick in they drain all the heat out of it and blow cold air as the engine keeps getting hotter and hotter.

Thermostats typically don't fit in backwards.

[Grady]

You changed the radiator and now you have a problem????



Step one, take everything off that you just put on. (paying attention to how it was installed)


Step two, read manual on how to assemble.



Step three, assemble the correct way.



Step four, drink beer and pat yourself on the back for a job well done!