So I’ve had a heat issue with my truck (1993 F150) since I got it. It blows hot enough, but not really hot like it should. In the winter my cab doesn’t really warm up until I’n half way to work already. So far I’ve replace the thermostat, the heater core, cleaned the ducts and checked door functionality, and flushed the coolant. The only thing I can think of now is that the water pump is weak enough to not get much flow through the heater core, but strong enough to keep coolant flowing through the block. What say you Oppo? Am I on the right track here? Or is there some other mystery I should look into first.

Completely unrelated xkcd for your time.