WHY DOES MY TEMP GAUGE AND MY HEAT GO COLD AT SPEEDS OF 60MPH OR MORE? P.S. 2.2 LITRE WITH 166,000 MILES ON IT.
Your engine uses a temperature regultaing device called a thermostat,I would start with that.
Please check the coolant level in the radiator (when cold), and consider having the cooling system flushed and refilled and a new thermostat installed. Your car is old enough to need a new thermostat, and they are not expensive.
I already changed the thermostat, and flushed out the heater core. somebody suggested the head gasket, i hope this is not the case.
Not likely headgasket (different symptons for headgasket) for you sounds possible you have air in cooling system (sending unit not in contact with coolant)
So try “burping” the cooling system. This might help:
already tried burping no change, also as the tempature gets cold outside,the engine does too. somebody please help me!!!