Thread: County cooling system

Unless you've got a different radiator, you've only replaced metal with plastic. The cap on the plastic should do exactly the same thing as the metal version. The pipe from the radiator to the overflow is at pressure - so no difference.

Originally Posted by fid-def

Ive replaced the metal expansion bottle on the 110 with a plastic one from a later defender. The overflow pipe from radiator is just open circuit not a pressurised system. Doesn't this mean it has more chance of over heating??

On my county there is a little hose that comes off the radiator under the left side radiator holding bracket and lead to the bottom of the brass expansion tank this hose is definitely pressurised. Taking this hose to a recovery bottle would cause it no to pressurise and would overheat or boil it the same temp but the pressure raises the boiling point stopping it boiling ( same as a pressure cooker). There is a small overflow line that goes from under the cap on the metal tank that sets the system pressure, so without that how would you fit your metal radiator cap.

Never really looked at what a defender has so maybe or you took some photo and sent them to me I could see what you have done.

Originally Posted by fid-def

Ive replaced the metal expansion bottle on the 110 with a plastic one from a later defender. The overflow pipe from radiator is just open circuit not a pressurised system. Doesn't this mean it has more chance of over heating??

If this is the one I'm thinking of, that has the pressure cap on the expansion tank. You need to pull out the radiator and take it to a radiator shop where they seal up your old expansion pipe and braze on a new radiator neck for a new pressure cap and expansion outlet.

In short, having the system unpressurised does increase the chance of overheating as it will lower the boiling point

I'm a bit confused about the cooling system on the county (4BD1 motor). The overflow pipe on the top of the radiator feeds into the expansion bottle. There's no radiator cap so as the temp rises and the coolant expansd it just flows out to the bottle. This means there's no possibility of a pressure build up. That said the bottle i have is off a later model defender and when I think back the old metal bottle had a pressure cap (I think) is my memory correct. I dont think the old bottle is out in the shed. Short of getting an old bottle are there any other options eg a newer design.

A.) Pics would be helpful

B.) In your last post about this, you said you had an expansion bottle from a later defender - and they have plastic pressure vessels and a pressure cap that acts the same as the metal version.

Are you now saying that you have something else? Did the defender your replacement bottle came from have a cap on the radiator?

If your radiator does not have a cap - you need your old metal bottle back.

Yes, the old can has a pressure cap

Later Defender came without engine and gearbox or radiator so no idea if it had a cap. Bottle looks the same as that on disco early series. Sounds like I need to find the old one.

Originally Posted by fid-def

Later Defender came without engine and gearbox or radiator so no idea if it had a cap. Bottle looks the same as that on disco early series. Sounds like I need to find the old one.

That sounds like a plan.
I would look for the metal one I just put one on my sons county.
The V8 county had the same setup as you are after. The plastic one sounds like it is off a 200 or 300 tdi they have two lines coming out the bottom.
Did you have a metal one before?