Expansion tank stealing water

[nelsonsx]

When I'm on track and cars getting heated up the coolant expands and fills expansion tank, obviously this is all normal. What's not normal is, it doesn't flow back once its cold. The expansion tank fills up then holds the water, and it also fills right up,then ends up splashing out the overflow and over engine bay. Only did couple stints at silverstone at japfest and the expansion tank stole my water. Got home and when looked next day it was still there. If I remove the rad cap, unbolt the tank and hold it up it symphony's back into rad so the hose is clear, for some reason the system won't draw the water back into the rad.
Any ideas

Cheers rich

[dukey]

Sounds like the rad is drawing air rather than drawing through the expansion tank.

[nelsonsx]

This is what I thought. But then thought if this was the case, and it was able to draw air, under pressure wouldn't that show as a leak, but there is no leak.


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[skyshack]

Replace the rad cap, it may be leaking at the upper seal. There are 3 seal points on the rad cap. 1: Top of neck, this is a low pressure seal. 2: Top of small dia neck, high pressure seal, bleeds coolant to expansion tank. 3: Suction valve returns coolant to rad, the small spring loaded disc on inner end of cap, seals against same bit of rubber as neck.

Get the coolant tested for exhaust gas.

[nelsonsx]

Il check those cheers. I tried a different cap and still did same so il check the area it seats on on the rad and check for imperfections.
Who would be able to check for exhaust gas


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[hooky]

If all is well, the coolant only expands a small amount and will only pass around 200ml to the expansion tank, even under extreme conditions on track, it is much more likely that there is air or gas expanding in the coolant system which expands much more when heated and pushes the coolant out of the system. The best case scenario is just a simple air lock in the system, worst case is a leaking head gasket or cracked block/head.
I had EXACTLY the same symptoms and it turned out i had twisted the block and Cracked Two liners!

I really hope yours is a simple bleeding issue!

[nelsonsx]

Well this is me. So it's going to be worst case scenario I already know this


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[nelsonsx]

Cheers for the replies guys. Il start looking into the exhaust gas test


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[green_rs13]

exhaust gas test is also known as a 'sniff test' you can just buy the kits or the 'special' fluid off amazon etc..

when my head gasket started to go it did what you describe. but I just kept pouring Kseal in till it exploded.

[nelsonsx]

that's the legends way to do it


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[BLAKTOOTH]

I fitted a breather tank to my system to stop that happening to mine. Seems to have helped.

[hooky]

I fitted a breather tank to my system to stop that happening to mine. Seems to have helped.

Very interesting, did you buy this as a kit including the lower rad pipe tee? if so where and how much?

[green_rs13]

looks like a sard bubble tank kit to me.

[BLAKTOOTH]

Sard/Greddy/Part Shop Max... all do them. Mine's a PSM one but I had to buy the lower rad hose fitting separately. Take a look at some Time Attack engine bays and they all run them.

[nelsonsx]

What's it actually supposed to do


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[Drifter]

What's it actually supposed to do


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I've got the same kit as Lee. It raises your water level higher which helps with top mount turbos, plus the way the tank is designed it helps pull air out of the system. You can see it working when you run up after changing coolant. On the bottom hose I tapped the ally housing to take the hosetail. I fitted one to my mates R34 as well as that was a twat to bleed without the throttle bleed points above the engine.

[BLAKTOOTH]

I've got the same kit as Lee. It raises your water level higher which helps with top mount turbos, plus the way the tank is designed it helps pull air out of the system. You can see it working when you run up after changing coolant. On the bottom hose I tapped the ally housing to take the hosetail. I fitted one to my mates R34 as well as that was a twat to bleed without the throttle bleed points above the engine.

Tapping into the ally housing's a great idea, wish I'd thought of doing that. Oh well, both ways work I suppose.

[nelsonsx]

Will normal silicone pipe be ok with the system pressure. Or should it be the reinforced pipe.


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[Drifter]

Will normal silicone pipe be ok with the system pressure. Or should it be the reinforced pipe.


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It'll be fine, coolant pressure isn't that high


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[nelsonsx]

That's cool then. I didn't know if 1.1 was above the rating for silicone hose.


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