Cooling tube blow out

[tmoretta]

Anyone else have any trouble with the flex coolant tubes? After complete system fill and engine up to temp. my driver's side rear flex tube started to leak where it fits into the rubber joint and then the rocker panel tube. When I loosened the hose clamp to re-position it, the flex tube blew out of the joint. I am now worried about the system design - with so many connections and joints.

[ssssly]

Sounds like a big air bubble.

[metalmaker12]

I agree, how much coolant in your system. With a stock wrx radiator the 818 capacity should be about 2.7gallons and with a larger koyo sized core about 3.25 gallons. So if you are under that you have sure in there and will cause issues. You gotta get a bleeder funel or make a bleeder at this point to get the air out. Here's some ideas36104 3610536106

[tmoretta]

so no problems with the design? - The flex tubes are secure enough?

[AZPete]

Factory Five has been supplying the flex tubes for decades to thousands of builders.

[wallace18]

so no problems with the design? - The flex tubes are secure enough?

The problem lies else where. These tubes have been proven for years. Sounds like you have either a air problem or incorrectly install. In 4 builds I have zero failures so far.

[ssssly]

Park it on a slight incline so the turbo filler tank is above the rad. Jam a skinny funnel in the turbo tank filler and fill till the funnel is half full. Start the car and work the throttle to suck in the fluid from the funnel. It'll burp out all the big bubbles. If the level drops fill it back up to half full and rock the throttle to get the little bubble out.

[metalmaker12]

Park it on a slight incline so the turbo filler tank is above the rad. Jam a skinny funnel in the turbo tank filler and fill till the funnel is half full. Start the car and work the throttle to suck in the fluid from the funnel. It'll burp out all the big bubbles. If the level drops fill it back up to half full and rock the throttle to get the little bubble out.

The lines are fine to use, they will just not be a durable as a solid set over time. But they don't leak if installed correctly or you don't have excessive air in system.

This will work with Wayne's upper coolant line modd only. The small coolant return line that goes to top of rad is problematic without his mod and will trap air.

[Bob_n_Cincy]

Anyone else have any trouble with the flex coolant tubes? After complete system fill and engine up to temp. my driver's side rear flex tube started to leak where it fits into the rubber joint and then the rocker panel tube. When I loosened the hose clamp to re-position it, the flex tube blew out of the joint. I am now worried about the system design - with so many connections and joints.


First thing,
Never open a radiator cap or loosen fitting on hot under pressure coolant system. I saw a certified mechanic get scalded pretty badly.

Everybody that commented above, I'm confused, why would a leaky coolant hose have anything to do with air in the system?
Bob

[ssssly]

The coolant system is designed to be relatively low pressure. When an air bubble gets caught in there it heats up and expands exceeding the pressure rating for the system. Pop.

[Bob_n_Cincy]

The coolant system is designed to be relatively low pressure. When an air bubble gets caught in there it heats up and expands exceeding the pressure rating for the system. Pop.

The radiator cap will not allow the system to exceed 18 psi. Then air or coolant is discharged into the overflow tank.
The coolant will reach this pressure of 18 psi everyday in normal operation.
Bob

[ssssly]

If there is an air bubble preventing flow it will not. It will blow out the nearest coupler.