OK so I am back on leave from the military for 2 weeks and have 1994 GMC Yukon 4x4 2 door SLE with 5.7 and auto. Since I been gone in the last 6 months it won't heat up. It has a new radiator and a new thermostat was installed. I thought it could be the thermostat but not sure. I am just looking for ideas. There is no heat or luke warm heat and the temp guage reads right around 100. It runs fine but there is no heat. It seems to be loosing about 1 quart of coolant every 2 months. Anyone got ideas for me. I only got till the 17th. Thanks all.