Not getting heat after water pump replacement
This is not for my truck, but for my dad's. Its a '96 ram 1500 5.2L 2wd. I got home yesterday from work, and he said when he was on his way home too when he noticed the truck began to overheat, the charging light came on, and he had a loss in power steering. I told him it had to be that his serpentine belt snapped if all that happened at once. So when I got home, I looked and his belt was still under the hood, but not on any of the pullies like I had thought. Well I then also noticed coolant was all over the engine bay, so I grabbed the fan blade and shook it, and realized the water pump had gone. So ~4 hours later in 10* weather, I had a new water pump in there for him, but once we started it up and let it warm up to finish topping off the coolant, we realized it wasn't blowing warm air...at all. So I reved the engine up to 1500 rpms and kept it there to try and get the t-stat to open. It never did take down any more coolant from the overflow, and when reving it, it began to blow out nuke warm air. Not enough to warm the cab though. Then once i left off the gas, it went back to blowing cold.
So my question is, what could it be? The radiator was replaced about 5 months ago after it sprang a leak. And a full radiator flush was done after. The pass. floor board is wet, but only because his window seal has a leak. Does not smell of coolant, so i sorta ruled out the heater core. I'm thinking maybe the thermostat is stuck, or those door flaps in the dash are stuck closed. The truck is not over heating at all now.
Was just curious if anyone knew what it would most likely be before I go back out in the cold to fix it.
2004 Hemi Orange Ram GTX #062