Radiator coolant

Tiny
ANESGASMAN1
  • MEMBER
  • 2001 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 147,000 MILES
Truck not reaching normal temp. Heater blowing warm air. Changed thermastat twice then water pump and flushed heater core and no change in temp guage or heat. Top rad hose hot and bottom cold. Two hoses to heater core hot. What's my next step?
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Saturday, January 22nd, 2011 AT 11:26 PM

9 Replies

Tiny
WRENCHTECH
  • EXPERT
It's mormal for the lower hose to be cooler than the upper. That just means the radiator did it's job.
With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If not too hot to hold, then you have to look at the actual engine temp and if that is up, if it is, then your looking at a restricted heater core.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
If they are both not too hot to hold on to, then you either have a restricted heater core or the system is not completely full and getting air pockets for some reason.
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Saturday, January 22nd, 2011 AT 11:49 PM
Tiny
ANESGASMAN1
  • MEMBER
The temp gauge is only reaching 160 degrees or lower. Both heater core hoses are HOT. I stated that I flushed the core already. Not restictions in flow. Lower hose isn't cooler its cold. After driving for 20 minutes still cold and no pressure built up in radiator and fluid inside is cold.
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Sunday, January 23rd, 2011 AT 12:30 AM
Tiny
WRENCHTECH
  • EXPERT
If the engine isn't building enough heat, there isn't much you can do about that short of covering the radiator and that would be dangerous.
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Sunday, January 23rd, 2011 AT 12:50 AM
Tiny
ANESGASMAN1
  • MEMBER
? Why wouldn't the engine build enough heat? It wasn't that cold when this started so the radiator doesn't need covered.
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Sunday, January 23rd, 2011 AT 12:53 PM
Tiny
WRENCHTECH
  • EXPERT
It's a cooling system, not a heating system. The engine generates it's own heat and the cooling system removes it. Yours is just working a little too good. The thermostat is the only thing that has the ability to bring the temp higher.
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Sunday, January 23rd, 2011 AT 1:34 PM
Tiny
ANESGASMAN1
  • MEMBER
How do I get it to work not so good so that I have heat? And why isn't it reaching normal operating temp. It is only at 145-160. Will the thermastat open if it's only at 160? The thermastat is 190 or 195. Should I change it to a 160 degree one? What's my next step?
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Sunday, January 23rd, 2011 AT 2:11 PM
Tiny
WRENCHTECH
  • EXPERT
The ONLY thing you can do is install a 195 thermostat and make sure it's working. If the engine can't generate more heat than that, there's nothing you can do about it beyond restricting the air flow through the radiator annd I don't recommend that.
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Sunday, January 23rd, 2011 AT 2:15 PM
Tiny
ANESGASMAN1
  • MEMBER
I did replace the thermastat twice and it is working. I tested it. Why won't the engine generate more heat? It has always reached 195. So what's causing it to not reach this temperature?
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Sunday, January 23rd, 2011 AT 2:18 PM
Tiny
WRENCHTECH
  • EXPERT
Closing out question
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Friday, March 11th, 2011 AT 4:35 PM

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