Little to no heat

[rigid]

The radiator is 3 years old. New heater core and blend door actuator two years ago. I can hear the actuator cycling. The tank and cap was replaced with the heater core. Barely warm at best. On the throttle it would get a bit warmer, but coming to a stop back to barley warm.
Some suggested water pump may be worn from prior coolant. I replaced it yesterday and the problem is still the same if not worse. The old pump still had the plastic impeller all in tact. When filling yesterday I filled through allen plug and ran it 15 minutes with the funnel still in it and topped off. I drove it 10 miles and then loosened the plug a bit to see small air bubbles come out. Topped the reservoir off and had a bit more heat, but not hot. This morning it would clear the windshield of light frost after 15 minutes. The same issue. At speed warm but nowhere near hot. The minute I'm off the throttle or at a stop sign it is cold. Zerex o5 coolant . Any ideas on what is next?

Thank you

 

[sota]

sounds like a blockage, either debris to the feed line, or a really stubborn air pocket. if you have ramps, put the front on them before pulling the allen plug.

maybe consider finding a shop that can do the vacuum trick on the cooling system?

 

[Ksat]

Did you replace the thermostat? If not, most on the forum here recommend using an OEM replacement.

 

[tommudd]

On some it takes a while to get all the air out
I had one that I replaced radiator, hoses thermostat for a young lady
She was waiting for me to finish it and darn if it didn't take at least an hours or so
tried every trick in the book, was even pulling parts off of mine

 

[Dirtyrat]

The radiator is 3 years old. New heater core and blend door actuator two years ago. I can hear the actuator cycling. The tank and cap was replaced with the heater core. Barely warm at best. On the throttle it would get a bit warmer, but coming to a stop back to barley warm.
Some suggested water pump may be worn from prior coolant. I replaced it yesterday and the problem is still the same if not worse. The old pump still had the plastic impeller all in tact. When filling yesterday I filled through allen plug and ran it 15 minutes with the funnel still in it and topped off. I drove it 10 miles and then loosened the plug a bit to see small air bubbles come out. Topped the reservoir off and had a bit more heat, but not hot. This morning it would clear the windshield of light frost after 15 minutes. The same issue. At speed warm but nowhere near hot. The minute I'm off the throttle or at a stop sign it is cold. Zerex o5 coolant . Any ideas on what is next?

Thank you

Design flaw!! Back flow your heater core to clean it out

 

[rigid]

Thanks for the suggestions guys. I will try to work through some of these this weekend.

 

[Duster]

For me this issue was air. How is your temp guage reading?

My advice is get the front up as steep as you can, put the heat on, run it with the cap off until it starts spilling out and you have to cap it. Then open the allen. You may even have to do it a few times and you may have to crack the cap and avoid getting burned.

Sometimes it is an absolute bear, and other times its not as hard. IDK.