Ok, 2 different problems Unsure as to why original overheat and rupture of the tank,.that much pressure is alot and not to alrm you but headgasket is possible. maybe t stat was it as well. the abrupt to red is not normal nor can an engine heat that quick no matter what cooling system problem. The ECT is a bi element sensor so one element goes to computer, the other to dash. I am thinking bad sensor. Click HERE
for that info. Per the low coolant. Here is some info that could? be root cause other than low coolant sensorNo: 26/02/05/NAS
Date: 17 February 2005
False Coolant Level Warning
AFFECTED VEHICLE RANGE: New Range Rover (LM) All
"CHECK COOLANT LEVEL" WARNING MESSAGE DISPLAYED
The vehicle may display the "Check Coolant Level" warning message even when the coolant level is visually within the correct range in the expansion tank. Incorrect specific gravity of the coolant mix can result in the "check coolant level" warning message being displayed.
VERIFY COOLANT SPECIFIC GRAVITY
If the customer complains of the above symptom, the specific gravity of the coolant MUST be checked prior to any other investigations or repair, such as the replacement of the expansion tank assembly or low coolant level sensor. The low coolant sensing system will not work correctly if the specific gravity of the coolant mixture is incorrect.
The specific gravity of a 50% anti-freeze solution at 20°C (68°F) is 1.075 (using a coolant specific gravity tester) and protects against freezing down to -36°C (-33°F).
PARTS INFORMATION: NOTE :A 50% mix of water and coolant is required for a refill. Topping up with either blue coolant is permitted for recent vehicles with factory fill BASF G48 coolant (blue). The 50% mix is required to obtain the correct specific gravity.
DDW WARRANTY CLAIMS: CAUTION : Mixing of the BASF G48 (blue) with Texaco XLC (orange) coolant can result in premature erosion of the cylinder heads or other cooling system deterioration. Unapproved blending of coolants is to be avoided.