03 Land Rover Discovery II is over heating. I Changed out the thermostat, there are no leaks. But I notice when the truck started to overheat the hoses were really under pressure. It was like the coolant wasnt flowing. Please help

 

Are you saying 'overheating' because the needle is rising above the centre mark?

Have you monitored the temperature using any other device?

 

The needle is rising. But also when I squeeze the radiator hose it is really tight. Like I said it is like the coolant is not flowing.

 

Ok, very first step is to stop running it at all and get a device to actually read the temperature. Either an OBD2 device like an ultragauge or an aftermarket temp gauge. The factory gauge is trash and doesn't even start moving until the engine is WAY overheated. Fingers crossed that you haven't killed your head gaskets or even worse slipped a cylinder sleeve yet.

First things first, remove your serpentine belt and see if you can spin the water pump by hand.

Second, what brand thermostat did you use? Remove it and drop it in some water on the stove to make sure it is opening at the correct temperature. If you got the Motorad brand, return it as defective and buy an OEM.

Third, take a water hose and make sure your radiator isn't clogged. Then also make sure your block isn't clogged.

What brand coolant are you using? What color coolant was in it when you replaced the thermostat? You should only be using universal green.

 

Alex brings up some good advice. Please note that the temperature gauge you are reading in your instrument cluster is a very poor tool in association with the actual temperature of your coolant. If the needle starts to move above halfway, your engine is already well over-heated. Unfortunately you haven't made yourself familiar with certain quirks related to the Discovery-2 and may very well have seriously damaged the engine, or predisposed it at least, to a lesser degree. It would be wise to ask all of your questions on this forum, follow directions precisely, and browse the threads to see what else should be addressed before you have more problems with the engine and drive-line. These engines are not able to handle over-heating and destruction is common amongst those who fail to take a serious understanding of this vehicle and preventative maintenance required to keep it operating somewhat reliably. You will find an abundance of Discovery2's at the scrap-yard and being sold for parts due to a few over-heating incidents such as your case.

 

All of the above.

Don't run it now until you have a strong idea what is going on.

 

Could be air bound...

Park it on a STEEP incline and open the bleeder with the heat on monitor the temps carefully.