Water Pump Failure Symptoms - no heat

[cwilkie]

Question guys. I changed radiators since I though it was the reason my truck was loosing antifreeze and warmer than expected. Well the new radiator is in as well as a new 180F thermostat. I have no heat. I had heat before I changed the radiator. I made sure to flush the radiator with water since I thought it was full of air. I bled the system properly. When the engine reaches operating temperature I am able to squeeze close both the upper radiator hose, lower radiator hose and even the elbow hose that connects the hose to the intake. Both heater core hoses are cold. I had heat for a few seconds when I removed the heater core return hose while the truck was running and then put it back on the radiator.

Let me know your suggestions because I am pretty confused.

[lowrollin70gmc]

If the hoses are routed the same way as before the radiator swap (which it sounds like) there has to be something blocking the flow. Having heat with the heater hose to the radiator disconnected would make me suspicious of the new radiator fitting. It's a long shot, but could the fitting not be drilled all the way through?

It's a long shot but easy enough to check with a hose disconnect and flashlight/screwdriver to probe.

[88Ironduke]

Could be as simple as an air lock in the heater core. It can be a matter of age, minor bits of garbage in the core and the air just won't flow out like it normally should. Have seen on numerous cars thru the years. Have gone so far as to hook up garden hose and punch air out the in the core, smartly hook the hoses up and minimize the air potential. The impellers will not generate enough pressure to bleed out external items at times. If the engine is running and temps are good and you had no problems before... Air lock.

Good luck
88Ironduke

[AirSpeed]

Maybe you got a bad thermostat? Maybe it's not opening.

[jhwkns]

If it's not the control's, your heater core is plugged.

[cwilkie]

Thank you for the suggestions. I will try them all over the next few days and keep you all posted. I flushed the heater core with water tonight and just water came out really fast. Faster than it does when the truck is running. The water pump is a reman cardone. I noticed there is a nous coming from the front of the engine now and there is a slight wobble on my water pump pulley. My next step is to take the belt off and wiggle the water pump pulley to see how bad it is. I hope it is not a water pump. Maybe my old radiator was never bad and I was loosing antifreeze from the water pump. I guess I have until September to solve this when the weather starts to get cold on North Dakota. I hope to solve this by the end of next week.

[SS Tim]

Since your picture does not show it I have to ask, is the coolant feed hose from the intake connected to the heater core lower/inlet? The upper/outlet is the return to the radiator or water pump depending on the installation.