Well this problem is opposite of the usual problem.My truck is not coming up to temp. During the summer months (110 degrees) I am fine ,no problem.Now here it is winter where the temp is 65-70 or lower,down to 20 degrees.I can drive my truck for about 1 hour (65 degree day)and the temp gauge does not even get above 120 degrees.I dont think thats good for the engine and milage.Where can I start to fix this problem?Thanks