get a Block checker at NAPA this will confirm the presence of hydrocarbons in the coolant.
If this is confirmed, then you have a
leaking head gasket,
a cracked head
or a cracked block

 

Check your oil as well. See if it is milky looking. This will definitely show of you have a head gasket leak. I wouldn't think that a thermostat is the issue because if it is stuck shut, then the coolant in the reservoir is not connected to the engine, so it can not boil it. If it is stuck open, then it would not overheat, it would have trouble getting up to temp. As far as boiling a thermostat, do not reuse it. It will not function correctly after it has been removed. Good luck and keep us posted!

 

Yeah thats my next thing is teh block test!..but there are no signs of a bad motor... No white smoke.. Oil looks like oil. If i top it off it runs good for about 30 min or until engine is heated then boils out of the reservior..and no leaks anywhere else.

 

Hi!!

I have the same problem with my Disco I. It started after I broke the plastic housing of the radiator fan. Replaced the fan and went to a volcano with the car fully loaded. It overheated and the coolant started boiling. The problem was a bad fan clutch.

Replaced everything and now I am loosing coolant from the reservoir. I am loosing about 1 liter per 100 miles. Yesterday I poured two different gasket sealers but it seems that it is still having coolant loses. I do not see any leak...

My thermostat is working because when the engine is turned on, the radiator hoses does not get hot until after several minutes of the engine running. Then, you can check that the hoses and the radiator suddenly get hot and the AC fan starts working.

I really would like to find an easy fix for this problem because I do not want to have to replace the head gasket.

Help will be welcome.

 

Do not pur engine sealer in a D1. The passages on the radiator are too small and you will plug it up. Might be plugged already from what you are saying. If you broke the shroud, replace it. It won't cool unless you do. If your expansion tank is black, replace it. They crack and leak. Check the water pump, have the radiator flow tested, and lastly, have the cooling system pressure tested by a mechanic.