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Truck is not heating up

Tiny
NITROE51
  • MEMBER
  • 1997 DODGE RAM
  • 5.9L
  • V8
  • 4WD
  • AUTOMATIC
  • 304,475 MILES
The antifreeze is cold in the radiator after forty miles of driving and has very little heat but does not overheat and the air conditioner lines are cold and dripping condensation like it has been running even the compressor is kicking in and out. I put in a new heater core flushed the radiator the heater hose's are all hot, but very little heat in the truck any help would be great. Thanks.
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Wednesday, October 12th, 2016 AT 2:54 PM

13 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
What is your temperature gauge showing? Sounds like the thermostat is stuck open. Try pinching off the upper radiator hose for a couple of minutes while the engine is idling to see if the temperature comes up.
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Wednesday, October 12th, 2016 AT 3:54 PM
Tiny
NITROE51
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  • 12 POSTS
The temperature gauge is sat 200 to 210 goes back and forth.
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Wednesday, October 12th, 2016 AT 4:13 PM
Tiny
NITROE51
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  • 12 POSTS
The upper hose and the two heater hose's are both very hot but antifreeze is cool in the radiator.
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Wednesday, October 12th, 2016 AT 4:16 PM
Tiny
NITROE51
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  • 12 POSTS
I do have a transmission cooler on it if that matters.
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Wednesday, October 12th, 2016 AT 4:17 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
Those temperatures and observations are perfect. If the heater hoses are too hot to hold onto for very long, that is proof coolant is circulating through the heater core. It is time to look at the temperature door in the heater box.
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Wednesday, October 12th, 2016 AT 4:25 PM
Tiny
NITROE51
  • MEMBER
  • 12 POSTS
What about the AC compressor running when the I have the heat on?
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Wednesday, October 12th, 2016 AT 5:13 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
The AC will run when the heater is in defrost mode. That is done to remove the humidity from the air before it is warmed and blown onto the cold windshield where it would condense and cause fogging.
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Wednesday, October 12th, 2016 AT 5:53 PM
Tiny
NITROE51
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  • 12 POSTS
Okay, so everything is good that way. Why are the AC lines cold and dripping water?
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Wednesday, October 12th, 2016 AT 6:06 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
They are supposed to be cold to condense the humidity in the air. That is what is causing the dripping water. That is the same as the water you see on the side of a carton of milk in the morning.

In the summer the comfort from the AC system comes from removing that same humidity, not from lowering the temperature of the air.
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Wednesday, October 12th, 2016 AT 6:23 PM
Tiny
NITROE51
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Okay, thanks. Why is the antifreeze in the radiator not getting hot and when I take the cap off? It is almost like there is no pressure in the tank.
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Thursday, October 13th, 2016 AT 12:48 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,870 POSTS
Radiators for the last coupe of decades are extremely efficient at dispersing heat. In fact, in cool weather you can run a Caravan engine at idle sometimes for 15 - 20 minutes without the electric fan even turning on. If your temperature gauge shows normal temperature and the heater is blowing hot air, there's no need to go looking for a problem that doesn't exist. The goal of the radiator and fan is to make the coolant cool, and it sounds like that's what is happening.
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Thursday, October 13th, 2016 AT 3:42 PM
Tiny
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Ok thanks for your time and knowledge it's greatly appreciated
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Thursday, October 13th, 2016 AT 3:50 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,490 POSTS
Good to hear, please use 2CarPros anytime we are here to help.

Best, Ken
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Saturday, October 15th, 2016 AT 12:14 AM

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