I have a 2001 Disco 2 with the 4.0l bosch v8 was having problems with overheating under load. Replaced the thermostat and all the coolant hoses as well did a head gasket replacement. I just got the car back together and am still having a problem with overheating. My first though was air in the cooling system but after draining and refilling according to the Land Rover Service manual the problem persists. When running the car will come to temp but the heater doesn't blow warm at all when adding more coolant the heater will work for a short while then go cold and the temp gauge will start to rise fast. This process is easily repeatable... I am at a complete loss as to what more I can do, and I would love some assistance if any of you can help at all

 

Sounds like a heater core issue to me.

Can you feel the hoses, after the truck warms up, and see if any of the hoses are cold to the touch or rather a noticeable different temp then the other hoses.

 

The hoses are empty. I have released pressure in them to allow coolant to flow and they just end up empty again. So both are cold

 

To be more specific, I am talking about the two hoses going into the firewall for the heater core.

 

I understand and those are the ones that I am talking about. One comes from the lower intake manifold and the other from the junction off of the water pump.

 

Did you run heat on high to force maximum circulation through heater core?

Also I know you bled by the RAVE method, but as a check you can open the bleed screw in the morning when the engine is stone cold to see if there is any air, this is the highest point and bubbles with gather there. if there is any room top off until it is full and replace bleed screw. If it is full when you open it then you know you have no air in the system.

 

I am not understanding how both of those hoses can be empty if you bled the system.

Do you recall how much coolant you put into the system?

 

Yes I did run the heater on full. Here is the situation. Was driving around fine after putting the car back together and refilling the cooling system to land rover spec. once I got to a hill the heat died and the car started to over heat.

 

Somewhere around 2 gallons... I think a little over that though

 

That does sound as if you still have air in the system.

You can try one of the two options

1. suspend the expansion tank above the battery with bungee cords. Open the expansion cap. Open the bleeder screw an be ready to tighten it, wait for coolant to come out of bleeder screw and tighten. Put the expansion tank back and top off with coolant. Repeat as needed

2. Jack the front of the truck up, run it with heater on full for 30 minutes, let it sit over night, top off the coolant from the bleeder screw. Repeat as needed.