I just replaced my heater core last year

Tiny
SEAN03
  • MEMBER
  • 1992 CADILLAC DEVILLE
  • 135,000 MILES
Hi I just replaced my heater core last year. It got used maybe a month because the water pump and water outlet went. I replaced all of those. I replaced the radiator also. I ran cleaner through the system last night. I ran it for 10 minutes and it was blowing cold. Is their a valve on this car that opens and closes to call for heat. I will also look at the heater valve on the inside to make sure it is turning when it calls for heat. Any suggestions. Thanks.
Saturday, January 5th, 2013 AT 6:53 PM

3 Replies

Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
The ac is controlled by the ac programmer it has the motor that controls the door. Sometimes the gear strips and u hear a grinding noise. Remove the glove box liner. U will see the rod going to ac door. Run the temputure go from 60 to 90 and watch to see if the motor is operating.
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Sunday, January 6th, 2013 AT 6:15 AM
Tiny
SEAN03
  • MEMBER
  • 523 POSTS
Hey I just opened it up yesterday. The motor turns freely. I watched it turn no grinding and no problem. I let the car run 10 minutes yesterday. I felt the big hose coming off the radiator and going to the water outlet. That was warm. The hose coming off the outlet was a little cooler going into the tee. The hose going from the other side of the tee going into the heater core was colder. Could the heater core be clogged. If it is how I just replaced it and the car rarely runs. Or could the thermostat be broken. Is their a way to test the thermostat. I know it is inside the water outlet. Thanks.
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Wednesday, January 9th, 2013 AT 9:42 PM
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Sorry our site has been down. To test the thermostat remove the top hose at the radiator. Remove the radiator cap and stick a hose in on medium speed. Start the car if the water keeps flowing out of the upper hose then you have no thermostat in. If not Let it run the engine will heat up then the thermostat will open. You will see water coming out of the upper hose. The hose automatically refills the radiator. If The thermostat is working properly water will come out of the upper hose then shut off them in the motor heats back up again the water will come out of the top hose again. Then you'll know the thermostat is operating properly. Then reattached the upper hose and filled the radiator up and the overflow jug. Restart the car with the radiator cap off. You will see the fluid in the radiator starting to go up and down. Then when the thermostat opens you'll see the water level drop in the radiator. As you rev the engine up look in the radiator you should see water flowing through the radiator core. Then just fill the radiator all the way up. Then check the coolant jug level.
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Friday, January 11th, 2013 AT 2:08 AM

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