Hello all, I’ve gotten so frustrated with my coolant system on my 99 disco 2 that I have come to make an account just to post a thread to see if anyone can help. So here’s the situation. The car was working perfectly fine idling and around 194° with my ultra gauge. There was nothing wrong with the car. I just brought it home to do some maintenance, along with all the maintenance I was doing I decided to change to a soft spring thermostat from Atlantic British. I also had new upper radiator hoses as well as a new lower radiator hose. I drained the coolant and replaced the hoses and thermostat. I refilled the system and I raised the expansion tank and I let the coolant bleed through the bleeder hole before capping it and I replaced everything and the engine started to overheat getting past 200°. I tried performing the bleed several times and even tried doing it once where I kept the cap open, pouring more coolant in and bleeding it while the car was running, and I am keeping the heater on full blast when I’m doing this. today I removed the thermostat, drained all the coolant again and checked that the thermostat was working by putting it in boiling water, after I saw that the thermostat opened. I reinstalled everything back in the car and tried yet again and no avail. The car started overheating again. I’m starting to hit a brick wall and I don’t know how to proceed. Any advice would be really helpful , I’ve tried so many different methods of bleeding the system but nothing seems to work. I know that my water pump is working because it was working before I change anything also I kept the bleeder hose open and expansion tank closed while the car turned on and coolant shot everywhere so definitely not doing that again. also, I forgot to mention that when I turn on the heater on full blast in the car every time I do this, I’m getting a lot of hot air blowing out. Please help. Thanks so much.

 

Having the heater on doesn't make a difference. There is always full flow through the heater coils regardless of what the temperature is set to.
Have you read up on the inline thermostat? That seems to solve most people's bleeding problems.

 

Fill it in stages.

Remove the small line to the top of the radiator.

Pour in about 1 gal of coolant. Wait 5 mins.

Pour in 1/2 gal. Wait 3 mins
repeat until coolant come out of the top of the radiator.
Replace the small line to the top of the radiator.
Fill until the reservoir is just above the fill line.
Turn on the heat to the interior.

Run the engine at 2000 RPM for 30 seconds.

Check and fill reservoir as needed.

It is important to wait for the coolant to fill all the voids progressively. If you add all the coolant at once, air will be trapped.

 

I would like to keep the engine as stock as possible, and I’ve already put too much money into buying the correct equipment for this set up.

 

If it was me, I would now put the original t-stat back in and see what happens (as it was running perfectly before you changed it).

 

If that soft close is not grey and OEM Land Rover it is probably junk. The non LR ones temp range is all over the place, some open a 180 some at 190.

 

You are making a giant mistake sticking with the OEM style thermostat. It is the single worst design flaw in the D2. It is lunacy to think any car manufacturer manufacturers any model that is perfect, much much less Land Rover. Literally dozens of 5 star reviews and hundreds of happy customers, a lifetime warranty if you are not satisfied. You have nothing to lose other than a ton of stress and countless hours bleeding and fighting with the oem system.

 

Had my coolant replaced by shop . Small bubbles still existed . After sitting overnight , I unscrewed the air relief , and added coolant , I did this for once a month . Those bubbles will bond internally , and sometimes they need time to let go . This is my experience .

 

I found filling through the bleed screw after filling the system normally helps drastically, as does holding the revs while cracking the bleed screw. The factory system can work well with a 180 t-stat and new everything, it's just painful and needlessly complicated to work on/bleed

 

Try this