Just replaced the thermostat, water pump, and all visible hoses except the one to the heater core and I’m running into a bit of a concerning issue. Admittedly I didn’t do the inline thermostat mod for the sake of keeping the vehicle as close to original as possible. I filled the cooling system with almost 2 gallons of some 50/50 coolant, and bled the system as I’ve seen suggested in the inline thermostat mod thread, and found that the vehicle was overheating. I let it cool, noticed the coolant had dropped a little, and then just tried to bleed and drive it again. Drove once more and sure enough it started overheating as I made my way around the block, so I made my way 2 blocks back into my driveway and it started to cool down again. So I let it sit all day and it seemed like the coolant dropped probably by like a quart or so. Feels to me like that’s a lot of coolant to add, but this is my first disco and maybe it needs some more coolant? I should mention there are no signs of any external leaks, so I topped it off again and just ran it this evening just sitting in my driveway with my OBDLink MX+ connected to see what the temp was getting to, I noticed the temp get to about 240 degrees Fahrenheit and the thermostat still hadn’t opened. As the gauge started to rise I just turned the car off and figured it was getting a bit late to fuss with it, so I was thinking that the new thermostat(which is a 180 degree thermostat) might have just come faulty from rovers north? Should I reach out and try to get a replacement or is there something else that I’m missing?

 

The cooling system takes 3.5 gallons for a refill,so if you did all those hoses and the water pump 2 gallons is short

You did not bleed the system correctly, the stock system bleeds completely differently.

1. Get your Disco level or point slightly uphill
2. Take the expansion take-off and raise it as high as it will go - remove the cap
3. Undo the bleed screw slowly in the T just behind the radiator
4. Wait for the coolant to come out - it may be almost instant the close the bleed screw off
5. Lower the tank - top as required and replace the cap
6. Start your disco DO NOT LET IT GET ABOVE 220 - you will do damage if keep overheating 244 is a red light overheated
7. Let it get up to temp 195ish will do
8. Now let it cool down - then open the bleed screw with luck you will get a dribble of coolant, if not raise the tank and start at step one again

It can take 3 or 4 tries to get it sorted out

 

Thanks for your help and clear instructions, got it bled properly and is currently running at a solid 194-204 ish!