how do you know if you have a head gasket leak? my truck has bad idling and feels like its always gonna die when i am at a stop light or when i am at home and i start the truck? i heard it could be the thermostat cause when i drive on the freeway my coolant comes out all over the floor...but anyways my idle is revs up and down or it just dies. k thanks for any help in advance

 

Well if you have coolant on the floor, you have a leaking heater core. If you run a compression test that should tell you, if you have 2 cylinders side by side with lower compression than the other 2, or if your seeing air bubbles in your radiator with the cap off. Is it carb or injection