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Radiator Overflow Is Filling But Not Emptying...

arrydjay

By arrydjay,
in Engines & Forced Induction

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arrydjay Community Regular

arrydjay

Posted
Posted

So lately I have noticed that my car has been using a bit of coolant.

Every couple of times I use it I just throw a bit of water in the radiator.

Today I decided to find out wtf is going on and I think I have figured it out.

My overflow bottle is hidden behind a custom panel I had made up so I havnt been able to check it.

Today I removed the panel and had a look and the overflow was full to the top with green coolant (a lot greener than the coolant in the radiator as I have been watering that down).

Its like when it gets hot it can overflow into the bottle but it cant get back...

I took the line off and blew through it and it isnt blocked or anything....

Any ideas?

jeffworld2 Veteran

jeffworld2

Posted
Posted

can just be a crap seal on the radiator cap, not the centre spring but the top of the neck to the cap. I had this on mine, with a munted neck the cap was still holding pressure but it was easier to suck air back into the neck than to bring water back through. Bit of silastic and all was nice again.
Frosty Grand Master

Frosty

Posted
Posted

Needs new head gasket and ARP bolts.

Smell the bubbles in the radiator, if they smell like petrol you are ripping the head off.

yep agree

can just be a crap seal on the radiator cap, not the centre spring but the top of the neck to the cap. I had this on mine, with a munted neck the cap was still holding pressure but it was easier to suck air back into the neck than to bring water back through. Bit of silastic and all was nice again.

and this 2

start of small and work your way up! will be a process of illimination

MagicMikeZ32 Veteran

MagicMikeZ32

Posted
Posted

can just be a crap seal on the radiator cap, not the centre spring but the top of the neck to the cap. I had this on mine, with a munted neck the cap was still holding pressure but it was easier to suck air back into the neck than to bring water back through. Bit of silastic and all was nice again.

Agree with this.

Coolant heats up, takes easiest path into overflow.

Cools back down, leak somewhere lets air get sucked in to fill the gaps as that is easier than sucking the coolant back up from the overflow.

HR32GTS 4DOOR Community Regular

HR32GTS 4DOOR

Posted
Posted

Had this problem on my old engine. Turned out the head gasket had a tiny leak, If I wasn't paranoid about my car I wouldn't have noticed. Not too hard a job to replace.

Does the coolant system stay pressurised after the car is left over night? and does the top hose feel rock hard when warm?

arrydjay Community Regular

arrydjay

Posted
  • Author
Posted

well i was running a 1.3 bar cap... swapped it today to a 0.9 bar one.

I also bought one of those chemical combustion leak tester thingos but it came up all clear...lll see how it goes with the new cap.

260tech Proficient

260tech

Posted
Posted

Agree with this.

Coolant heats up, takes easiest path into overflow.

Cools back down, leak somewhere lets air get sucked in to fill the gaps as that is easier than sucking the coolant back up from the overflow.

^^ What he says is as good a place as any to start. Renew overflow hose (if you haven't already) from radiator to o/flow bottle & see how you go.

Cheers GW

blah_blah Grand Master

blah_blah

Posted
Posted

Dang! Same thing happens to me.

Overfill bottle fill but radiator keeps on emptying. Think I too have a leaking head gasket from boiling the car last year.

Any consequences of having a leaking head gasket? I might just leave it and keep filling the radiator....no monies

scotty nm35 Grand Master

scotty nm35

Posted
Posted

Dang! Same thing happens to me.

Overfill bottle fill but radiator keeps on emptying. Think I too have a leaking head gasket from boiling the car last year.

Any consequences of having a leaking head gasket? I might just leave it and keep filling the radiator....no monies

I drove my VQ for a year like that, without realising it was the head gasket. It let go in a big way on the dyno during a tune.

Get a carbon test done on the coolant, it should show up any combustion bubbles making their way into the cooling system.

arrydjay Community Regular

arrydjay

Posted
  • Author
Posted (edited)

yeah I suspected my head gasket, but the combustion gas test came up all clear.... my mates S14 has been running like shit and we couldnt figure it out so I did the test on his and the dye changed colour straight away which means he has headgasket issues.

Its an awesome bit of kit... I got mine from repco for $130, just ring and make sure they have got one first as lots of places were out of stock when I was looking for one.

Here is how it works for anyone who doesnt know....

Edited by arrydjay

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