Novice needs advice re overheating problem.

Hi all, hope that you can offer me some advice on this problem. First of all I am ashamed to admit that I only have a basic knowledge of vehicle maintainance but before I rush off to my local helpful landrover specialists I just thought id run this by you to get your thoughts. Why do these things always happen on a bank holiday weekend!!!
I drive a 1996 300tdi which yesterday started overheating. I had to stop several times on my way home and wait for the engine to cool right down before adding water to the system which fortunately i carry in bulk due to having dogs!
I managed to nurse my vehicle home and the dogs loved the amount of walks that they had in the process!
I have no idea where the water is being lost as there are no leaks...however the pressure on the system was high...the water was literally boiling!
I have drained the system and refilled it and the vehicle ran fine until i came to a steep hill when the overheating occurred again fortunately close to home.
Off to the garage on Tuesday but any indications as to what the problem could be?

First thing id check would be the thermostat. If its stuck closed, when the engine coolant gets hot, it wont allow coolant to circulate via the radiator, thus causing the overheating!

Easy way to check is to get engine up to operating temperature and check the hoses going to the radiator, if they arenet hot, id suspect the thermostat is the problem. Npt expensive to fix, and its a job u can do yourself

Thanks KaOs. I will check in the morning...just off to the pub to celebrate Sunderlands title win..or is it to drown my sorrows over my discos overheating!! As for doing it myself if that was the problem..is it that easy??

Ok had a quick drive in it and got it up to running temperature. The temperature guage rose again. Checked the pipes leading into the top of the radiator. large pipe in middle was hot. large pipe on the right (as you look from front of vehicle) was cold. hope this helps??? told you i was a novice!!

Out of politeness I always like to leave what the problem was. Its rude not to! Unfortunately on this occasion it was the cylinder head. A little annoying as it was only replaced 12 months ago but for some reason the garage that I had the work done at hadnt tightened the bolts properly!! Annoying when you pay people good money to do a good job. Fortunately I have found a fab local specialists that are very reasonable in their prices and know Landrovers inside out.

I'd have taken it back and driven it through their office

Its amazing what you hear about a garage when you stop getting your work done there!