Series Land Rover - Losing Engine Coolant
If your Series Land Rover is fitted with the flat topped radiator, used initially with the Series I,II & IIA models then you have some additional tolerance towards coolant loss as this radiator is 4-cored. The problem still needs to be resolved however as soon as possible.
It may simply be a poorly fitting radiator cap allowing water vapour under pressure to escape.
Look for wet areas on hoses, near to hose joints and close to the seams and tubes of the radiator. White stains from chemical coolant is usually visible where leaking has occured. Turning off the engine followed by careful observation may reveal the leak. A temporary fix may be possible with epoxy resin if the area can be dried and cleaned well first, but brazing is usually required before long.
If you find water dripping from behind the main fan it will probably be due to either a perished rubber seal in the water pump or a damaged thermostat housing gasket.
Coolant stains on the side of the engine could be coming from pin-holes caused by corrosion of the engine cup plugs. The older your vehicle is, the more this is likely to happen. Cup plugs vary in diameter according to engine type. They are simply a press fit, but need to be carefully chiseled through and pulled out. A temporary fix may be possible with epoxy resin if the area can be dried and cleaned well first.
Slow loss of coolant can be handled by occasional topping up, but allow about 15 minutes for the engine to cool before removing the cap. Allowing the engine to run hot for long periods will risk damaging water and oil seals and this will just lead to more strife.
Liquid radiator sealants are available and they can be very effective. They should only be regarded as a temporary fix though.
An alternative cause of coolant loss is internally within the engine. If the cylinderhead gasket is damaged, then coolant may get into the cylinders. Indications of this are white exhaust smoke, loss of engine power and bubbles seen in the top of the radiator when the engine is revved.