Engine Cooling problem
2000 Dodge Ram V8 Four Wheel Drive Manual
Recently my 2000 Dodge ram overheated for the first time. I turned on the heater and rolled down the windows and slowed. At first the heat blew cold-then hot and cold intermittently before blowing hot. The engine cooled. At home I checked the coolant level and it was low by approx. 1 gallon which I replaced. No visible leaks, no collant in the oil.
The vehicle did not overheat again for approximately two weeks. Today taking the kids to school the engine ran hot shortly after turning on the defrost and when I got home about a cup of coolant spewed out the radiator cap. The engine cooled and I had to go to work. It was running fine but I decided to see what would happen if I turned on the defrost. The engine promptly heated to the high upper end of the operating range and wouldn't come down until I got off the freeway where it promptly cooled. Also, the upper radiator hose was hot so fluid must be circulating. Ideas?
If you had to add 1 gallon of coolant, you definitely have a leak somewhere (external or internal), or your radiator cap is not holding the pressure.
Pressure test your cooling system. You can buy some dye; it should help you to detect the leak.
Make sure you check everywhere, from the hoses, water pump, intake gasket etc.
If you still can't see any external leak, you may have an internal one; do you have a lot of white smoke coming out of your exhaust?
Do a compression test on each cylinder. A low reading would indicate a leaky head gasket.
You may also have a cracked head or block.