Initially there was a sudden spike in temperature with no heat inside the car., I replaced the thermostat , still there was a intermittant gurgling bubbling sound from the reservoir tank. I had the coolant tested for carbon monoxide contamination and it showed there was gas in the coolant.
Make sure you do both sides, and with that mileage on it why don't you flush out the engine afterwards, get alot of the sludge out, hell I would pull the pan afterwards and inspect the pick up tube for blockage, it is common.
*Dealer cost info only*
Not being savvy in this area, I just know that I had a leak at the head gasket on my 97 Disco. On my invoice (from dealer) it said "Leak at cyl head gasket. Replace cyl head gasket and associated parts replace all cooling system hoses and t/stat in conjuction with gasket repair." Listed was about 7 1/2 hours for all of this. Labor $1,044, and parts $714.
Oh, looks like the head gasket labor part was $852.00 plus $400 parts.. Just in case the info helps! Michele :confused