1991 Chevrolet G Series Van (G20) Q&A

1991 Chevrolet G Series Van (G20) Question: no heat

heater blows cold air when turned on. -
Answer 1
themostat stuck open or heater core plug -
Answer 2
could be heater control valve located just in front of heater core -
Answer 3
I noticed mine blowing coldish on the feet only this winter when I took it for a trip. -
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No sign of leak on the engine, but under the passengers door.... Excessive amount of coolant ...Very strange!!!
Van starts up and runs fine when cold. Sea light stays on. Once truck is up to speed it runs fine. When I give it gas it has a misfire. Temp needle doesn't move above 100.