Expansion tank on TD5 Defender

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lightning

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High Peak
My 2005 Defender seems to vent a few drops of water via the expansion tank cap. It's not enough to affect the water level, but every time l lift the bonnet (about once a week) to check the oil etc the tank shows a few drops of coolant on the outside.

I seem to recall that our last Defender did this as well, l am hoping it's not a sign of anything serious.
I never had to top up the water on that one either, but if l did put any in it always ended up just below the middle of the tank.

Does the cap itself ever need changing? I will try that first.
 
Check for cracked bottle, replace cap with new.

Go for drive and see how hard rad hose goes
 
If it's any comfort, mine does this too. The fluid hardly goes down but I often find drops of coolant on the outside of the container. I was wondering whether the head gasket might be blowing a bit but in 35000 miles it hasn't shown any further signs of a blown head gasket so I've ceased worrying. I think the fluid sloshes around as you drive and gets pushed out of the breather on the top of the cap by the 1.4 bar operating pressure.
 
I went for a drive, gave it some stick, stopped, and the radiator hoses were not hard. I'll fit a new cap and just keep an eye on it.
 
Well, l tested it again and the radiator top hose is harder after a drive, although l imagine some pressure is normal.
I am still able to squeeze the hose in with my thumb and finger, but not right to the centre. Somebody with a stronger grip might manage it though!
If there's a problem l take it the top hose is rock hard and cannot be compressed with a finger and thumb?
 
Somebody said that it should feel a bit like a tennis ball. Much harder and it could mean that you're getting some pressure from a leaky head gasket.
 
2.2 and 2.4 Tdci uses the same bottle and they do it on loads especially if worked or heavy towing. I see loads everyday so I'm not bullsh1ting
Most need a very minor top up I reckon ul find a new cap does it soon after but it seems to vary per vehicle
 
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