Hey this has been doing my head in.
I put in coolant and it spits it out at a great rate. I keep topping it up with water, after about a week of topping it up it would be nearly all water and then it does not use any water. I think its fixed itself so i put coolant in and it does it again! Gone through 30 dollars of coolant already!
I don't have a clue what is going on anyone have any ideas?
Cheers Ed

Oh didn't mention its comes out of the overflow on the top of the radiator

if your only topping it up with water when its spitting it out then eventually the coolant will be so watered down that it will look to just be water

dont know why it would stop spitting it out once its only water though

and you dont have a recovery type cap on there do you? if you do and dont have a recovery bottle then it will spit the water out when it gets hot and then try to suck it back up when it gets colder

Are you using pre mixed coolant or a mix your self coolant??

Mix yourself coolant.

Are you pouring this in and then the water or pre mixing and pouring it in the radiator?

Are you filling to top of radiator, your meant to leave 20mm or so for expansion.

Use a recovery bottle and correct radiator cap with plastic valve and you won't loose coolant.

As has been said if you have a overflow nozzle on the radiator and no overflow bottle the radiator will loose coolant/water as the mixture expands and when it cools down it is drawing air into the system instead of coolant. Get your self a overflow bottle and this should fix your problem.

I have tried absaloutley everything. It is a completley stock cooling system on a 71 model. I mix the coolant before putting it in and am mixing it to the instructions. It has no recovery system and isn't spose to. If it has coolant and I drive to work which is 40 k's it will use half a litre but with water it does'nt use a drop. It has me stumped

And it is the correct radiator cap because I thought that could be it so I checked