I replaced the water pump in my 02 XJ8. Left radiator hose is still cold. Right one is warm. Got good heat. Cooling fans cycle. Temp gauge is in normal. Does left radiator hose cold mean there is air or that thermostat is still closed? The little tiny molded hose that comes from thermostat area to the fill reservoir is HOT.

 

Drive it a few days and check it occasionally, monitor the temp guage, ...maybe its female and naturally cold?...lol

 

Or its the thermostat?

 

Thermostat is what I am thinkn....cause it should be hot if thermostat is working properly i would think.

 

Technically said, ..yes..but I'm pretty sure the heating core is on the other side of the thermostat opening. So if the heater works?

 

Very likely thermostat. Also know, if the car is cold it takes quiet a while until it heats up. Also if outside temp is low it stays quiet low as the radiator is very effective.