Cooling System
Discussion
A slightly odd reques but...
My recently acquired '94 Wrx had a leaking header tank when I got it and on it's first longish run after an on boost run down the A303 it sprung a leak in the top rad hose.
My thoughts are veering towards the possibilty that one of the headgaskets have gone but so far the combustion gas test has come up negative and there is no coolant blowing out into the expansion tank when on boost.
However there seems to be a lot of pressure in the system. If I let it idle from cold then everything seems fine, not too much pressure thermostat opens and the fans cut in.
If you put your hand on the top hose and squeeze it you can feel the hose expand when you increase the revs so that the turbo is boosting. This is less pronounced when the thermostat is open.
Am I just feeling the water build up from the pump against the thermostat ?
Something doesn't 'feel' right to me but I haven't spent any time around this engine setup to know if what is happening is normal or not
They can be b
ds to fill properly as the header tank is pretty much the same level as the heater core, which can lead to pockets.
A good tip is to jack the front up a little, thus making the heater core lower than the tank, allowing it to be filled easier. Also if its jacked when the system is burped, the air makes its way up and out without getting stuck.
ds to fill properly as the header tank is pretty much the same level as the heater core, which can lead to pockets.A good tip is to jack the front up a little, thus making the heater core lower than the tank, allowing it to be filled easier. Also if its jacked when the system is burped, the air makes its way up and out without getting stuck.
Well I found one problem, I snapped the top hose inlet of the rad clean off removing the top hose ! It looks like the original one, the plastic is obviously quite brittle.
At least a new rad will rule out any blockages in that and I spotted a potential leak on the side of it but didn't get a chance to pressure test it before hamfisting
At least a new rad will rule out any blockages in that and I spotted a potential leak on the side of it but didn't get a chance to pressure test it before hamfisting
New rad in this afternoon at work and spent a good while getting her bled up.
Seems to have resolved the issue so it must have been an air bubble somewhere
Bleeding method I used after reading around was as follows;
Take the thin hose from the rad to the header off at the header tank end.
Find a funnel that you can fit tightly into the header tank.
Slowly pour in your coolant mix of choice with your finger over the metal pipe the hose came off until it won't take anymore.
Squeeze the top rad hose with the small hose you disconnected in the other hand, cover the end with your finger and release the rad hose. Repeat until when squeezing the rad hose coolant squirts out of the little hose.
Start her up and let run until the thermostat opens and the fan cuts in, top up the coolant as required.
Blip the throttle several times, if air bubbles are still coming out keep going until at idle the water in the funnel remains bubbleless !
Fill the funnel a little, switch off and allow to cool down. The level in the funnel will go down slightly.
Put the rad cap back on, allow to heat up again and check for leaks now the system is pressurised.
Seems to have resolved the issue so it must have been an air bubble somewhere
Bleeding method I used after reading around was as follows;
Take the thin hose from the rad to the header off at the header tank end.
Find a funnel that you can fit tightly into the header tank.
Slowly pour in your coolant mix of choice with your finger over the metal pipe the hose came off until it won't take anymore.
Squeeze the top rad hose with the small hose you disconnected in the other hand, cover the end with your finger and release the rad hose. Repeat until when squeezing the rad hose coolant squirts out of the little hose.
Start her up and let run until the thermostat opens and the fan cuts in, top up the coolant as required.
Blip the throttle several times, if air bubbles are still coming out keep going until at idle the water in the funnel remains bubbleless !
Fill the funnel a little, switch off and allow to cool down. The level in the funnel will go down slightly.
Put the rad cap back on, allow to heat up again and check for leaks now the system is pressurised.
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