Just a thought, sometimes if the coolant is low enough, the temp can look much lower than it really is because there's no coolant making contact with the sensor. In a DII, the gauge isn't accurate anyway.
I have heard of pieces of the pump gears getting jammed and cracking the front cover. I've never seen it myself, so I can't say 100% for sure, but it seems possible in theory at least. Usually by the time the pump gears break, the inside of the front cover is worn or sometimes even scored (especially if the gears break into bits). The question is... if the pump is shot, has any other damage been done to your engine?
Good luck with it! I hope everything works out for you.

 

I've seen this with much older cars. I had a few where the temp would actually drop when it was low.

 

Yes, this is the kind of thing I was thinking of. I've never run my Disco low on coolant so I'm not sure what it would do in this case. I think one of my old Volkswagens would show low temp when the coolant wasn't in contact with the sensor.

 

if the sensor is not surrounded with coolant it if give you a false reading

 

My VW Golf did that! It exploded for different reasons, but when most of the water escaped, it dropped temp level, so I knew to add more.

I had a Vauxhall Chevette that also acted like that.

 

Exactly, I think it was my '89 Jetta that did that. I've seen it in other cars over the years too. Usually someone thinking their thermostat was bad because the gauge would read low and the heat didn't always work right. Really it was just a matter of not enough coolant to run either. Many of them have really small, hard to find leaks. I think that's why, the owners don't see a puddle and never realize it's leaking until their radiator is empty! It really pays to open your hood and have a look around every once in a while!

 

Well today we started tearing the motor down. We started with a pressure test on the coolant system, well that clearly showed that the radiator is separating on the drivers side, it leaks at the joint between the side plate and core. Needless to say only about a Coke cans worth of coolant came out of the radiator when we drained it.
Next we moved to the oil pan and front cover. Well the harmonic balancer bolt was only hand tight! After that was removed you could see the hole in the cover that leads into the oil pump cavity. Now to the photo's that are worth a thousand words.

















Poor,poor Rover





The shopping list, please inform me on the best and CHEAPEST place to find these parts.

 

I would say Lucky8.

 

Abran, if you are to test pressure with an opening that large in the radiator would it fail to show leaks in tighter places like, I don't know, head gaskets for example?

 

Wow! I don't know how Land Rover makes their parts so weak???

Land Rover, Below and Behind...