heater core coolant flow?
heater core coolant flow? Got a tuff one here, I have tried the search function & found very limited info.
My problem is I do not get any hot air from my heater. My set up is a 5.3 vortec (mechanicly all stock with 2500 miles) & a new Vintage Air "compac" unit. I have checked to insure the heater control valve is functioning properly. I have let the motor run for more than 30 minutes with no signs of overheating. But I am not convinced the water pump is circulating because I do not see water flow when viewing from the rad. cap, B.T.W. the water reads a consistant 200 degrees at the rad. cap, but the bottom of rad. is not very hot. I know there must be others on this board with similar set up. Any help would be much welcome. Thanks
Larry
My problem is I do not get any hot air from my heater. My set up is a 5.3 vortec (mechanicly all stock with 2500 miles) & a new Vintage Air "compac" unit. I have checked to insure the heater control valve is functioning properly. I have let the motor run for more than 30 minutes with no signs of overheating. But I am not convinced the water pump is circulating because I do not see water flow when viewing from the rad. cap, B.T.W. the water reads a consistant 200 degrees at the rad. cap, but the bottom of rad. is not very hot. I know there must be others on this board with similar set up. Any help would be much welcome. Thanks
Larry
Similar Problem with my Dodge Truck. When its real cold, the heat only blows HOT when accelerating. Idling it is only warm/cool. Replaced fan clutch, flushed cooling system, flushed heater core, inspected water pump and still no change. I would say check out the impeller on the water pump, any missing teeth will indicated a bad pump. Also what kind of fan are you running? I'm assuming electric. Are you sure it is turning on at the proper temperature? If' you're running a clutch fan, make sure it is not sticking, should spin freely when engine is off and cool. 
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I occasionally have the same problem with my conversion. I never really did figure out how to eliminate it 100%. Best I can figure is it is caused by air pockets. The way my system ended up is that the heater core is the highest point in the system, the upper rad hose is the second highest, and the radiator cap is 3rd. If the coolant gets low, the heater core becomes airbound.
I figured out that I needed to put one of those "flush" T`s up right next to the heater core inlet. Since then everytime I noticed that there wasn`t much heat coming out I cracked the cap open with the engine running and some air always comes out, then antifreeze. Then I have heat again. I want to come up with a more permanent solution, but it has not been a priority yet.
Just make sure you don`t have a air pocket in the heater core, these engines seem to be very sensitive to air in the heater lines.
I figured out that I needed to put one of those "flush" T`s up right next to the heater core inlet. Since then everytime I noticed that there wasn`t much heat coming out I cracked the cap open with the engine running and some air always comes out, then antifreeze. Then I have heat again. I want to come up with a more permanent solution, but it has not been a priority yet.
Just make sure you don`t have a air pocket in the heater core, these engines seem to be very sensitive to air in the heater lines.
