Cooling issues...

[MWP]

Hi all,

First this is not a Toyota, but i guess itll apply to any car so i hope you guys can help.

When the engine is running it runs smooth, runs cool, and all is ok.

When i stop the engine however, the engine starts to boil-over into the coolant overflow tank.
It does this for quite a few minutes and at such a rate that it spills most of the contents of the overflow tank onto the ground.
Then when the engine is cool, ill check the radiator and find it needs >1L to top it back up again.
It does this ever single time i stop the engine... so as you can imagine, filling up the radiator all the time does become quite annoying.

Also, when the engine has cooled down, the top radiator hose colapses in on itself.

I have tried a new radiator cap, but 2psi lower pressure than the standard one (in an effort to stop the hose colapsing)... the boiling over after running still happens, but it has solved the hose problem.

Does anyone know why this is happening??

The normal cap is 16psi, the one i tried to stop the hose from colapsing is 14psi.
To me it almost sounds like it actually needs a higher rated cap to stop the boiling over.

Thanks for any help.

[SL666]

sounds like it had a non-recovery cap on it before..

maybe coolant? sounds like its *NEARLY* cooking when you are running it (i assume its got an engine fan?) and then when you stop the coolant is getting just hot enough to boil.. some anti-boil might put it up high enough to stop this?

you could also check that the overflow hose seals to the filler neck to make it suck any vented coolant back in..

[MWP]

sounds like it had a non-recovery cap on it before..

Ahh, that would make sense.
Anyway to check by looking at the cap?

maybe coolant? sounds like its *NEARLY* cooking when you are running it (i assume its got an engine fan?) and then when you stop the coolant is getting just hot enough to boil.. some anti-boil might put it up high enough to stop this?

The coolant is all new, and has probably been completley replaced now anyway from me continually filling it back up.

you could also check that the overflow hose seals to the filler neck to make it suck any vented coolant back in..

Not quite sure what you mean here....
Do you mean that a leak in the overflow pipe might not leak coolant out, but might let air back in instead of drawing coolant back in?

[SL666]

so you have put in actual anit-boil type stuff not just water?


basicly yes.. sometimes theres a little leak if the overflow hose doesn't seal well against the little port on the filler neck, so when the engine cools and it tries to suck the coolant back in, it only gets air..

Anyway to check by looking at the cap?

yes, but not that i can describe without looking at one

google rocks..

http://www.are.com.au/feat/techt/imp...diator_cap.htm

[MWP]

Well its proper radiator coolant, so i guess it has anti-boil aditives.

Ill check for leaks, thanks for the tip.

They are some nice diagrams, thanks, ill see what the deal is with the current cap tomrrow morning.

[SL666]

I'd check the label on the coolant, sometimes it only has anti-corrosive properties..

[TooF]

changed the thermostat ? a bung themo can be causing it to almost overheat then once flow has stopped boil over as mentioned above.

[MWP]

The thermostat was changed about 3 months ago after a BHG repair job (done at a dealership), so i assume its ok.

[30psi 4agte]

what sort of condition is the radiator and water pump in ???

This can have a big effect on heating

[kingmick]

first off, this is a V8 chev oe ford we are talking about? or one of there 6's?

[BigBadBenny]

get a new radiator cap, one rated for the application, DON'T get one at a lower pressure
The top hose is colapsing because it's not allowing water to return.
A recovery style cap has basically two seals with a valve inbetween. A non recovery cap one has one seal, this is very easy to pick.
Benny