cold air coming out of heater when engine is warm?

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jasonperry77

Junior Member
Joined
Dec 5, 2013
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1
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Ram Year
2006
Engine
5.9 cummins
im in oregon and we have had a cold few weeks. lows around 15. anyways im looking for some advise. i have my trucks block heater plugged in overnight and in the morning on my way to work i notice my temp guage go up to about the middle of the guage and warm air comes out of the vents. then the guage dips down to almost cold and cold air starts coming out. as i drive the guage goes up and down up to 5 times sometimes getting cold air then warm air. then the guage almost pegs into the red and then it stops in the middle and stops doing that. thermostat? any info would be much appreciated. oh. and i have a 06 2500 with the 5.9 cummins. thanks.
 

HolyRamBatman

Senior Member
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Sep 2, 2012
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Location
Deep in the Heart of Texas
Ram Year
96
Engine
5.9
Welcome to RF.

Sounds like a sticking t-stat or clogged heater core. Weird symptoms.
I'm not familiar with Cummins but the heating should be close to the same.

A bump for more knowledge.
 

marx82

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Sep 22, 2013
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Location
Sweden
Ram Year
2013
Engine
Hemi 5.7
did it come suddenly, or has it been up for a while?
 
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