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84 K20 "Ethel" Not an Sbc/NV4500/241C

Semi restoration of a 1984 K20 pickup. 5.3 LS, nv4500, np241c.
Overview Gallery Discussion
Bent77 said:
Check the blend flap and the hoses.


I thought you lived in Death Valley. Stop whining
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It’s cold enough to want the heater, and I checked this morning the motor still runs at 190-192 that it always does, I cleaned the heater box out before I installed it. The flap is working, I can switch between defroster and heater Just fine. The core is not leaking either.
 
I've seen heaters quit working before engines overheated. I cant believe your engine runs that cold. Most newer vehicles like my wife's 2008 Yukon XL Denali with a 6.2L runs right at 210 on the gauge all the time.
We used to have a 97 Jeep Grand Cherokee with a 5.2L v8 and I didn't like that the engine ran at 210 all the time so I went down one step with the thermostat and after that the heater sucked so I had to go back up to the factory stat.
 
Truckman4life said:
I've seen heaters quit working before engines overheated. I cant believe your engine runs that cold. Most newer vehicles like my wife's 2008 Yukon XL Denali with a 6.2L runs right at 210 on the gauge all the time.
We used to have a 97 Jeep Grand Cherokee with a 5.2L v8 and I didn't like that the engine ran at 210 all the time so I went down one step with the thermostat and after that the heater sucked so I had to go back up to the factory stat.
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Yea it runs that cold without the fans on and in 120 degree temps on the freeway. It is rock solid and only comes up without the fan on in traffic.
Also remember the gauge on newer stock vehicles is sanitized now to prevent the owner from seeing the minor fluctuations in coolant temp.
 
Did you swap in an aluminum heater core?
They have a higher fin density and so it's harder to blow air through it and most of the air blows around it. I had the same problem with lukewarm heat and so I added some adhesive backed foam (like you'd put around a window A/C unit) around the edges to seal it and force all air through the heater core. Ever since I get plenty of heat!

Also make sure your blend door cable is adjusted properly so that it fully seats.
 
Chevy305 said:
Did you swap in an aluminum heater core?
They have a higher fin density and so it's harder to blow air through it and most of the air blows around it. I had the same problem with lukewarm heat and so I added some adhesive backed foam (like you'd put around a window A/C unit) around the edges to seal it and force all air through the heater core. Ever since I get plenty of heat!

Also make sure your blend door cable is adjusted properly so that it fully seats.
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No it’s a brass core. I think @Bent77 and you are onto something with the blend door. I’ll check that tonight. Thanks guys!
 
Even with the engine running cooler than normal in mine (155-165*) I can still get cooked out of the inside of mine. You don't have to get a temp gun. Just feel the temps at the firewall with your hand. Both lines should be similar in temp. If there is a significant difference, the core may have a blockage. If they are similar, I'd look closer at the temp door not moving correctly with the slider on the control head.
 
ZooMad75 said:
Even with the engine running cooler than normal in mine (155-165*) I can still get cooked out of the inside of mine. You don't have to get a temp gun. Just feel the temps at the firewall with your hand. Both lines should be similar in temp. If there is a significant difference, the core may have a blockage. If they are similar, I'd look closer at the temp door not moving correctly with the slider on the control head.
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Ok I’ll check it
 
sreidmx said:
It shouldn’t be but I guess air could be getting in and cooling it off..
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Well I mean more like the core has no Coolant in it and it's bypassing the core completely. In the square body the core is up kinda high its hard to get all the air out sometimes. Just a thought
 
SpeedlabDan said:
Well I mean more like the core has no Coolant in it and it's bypassing the core completely. In the square body the core is up kinda high its hard to get all the air out sometimes. Just a thought
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I do hear a gurgling from time to time so it’s quite possible..
 
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