Engine will not warm up

Tiny
DAVE MACE
  • MEMBER
  • 1994 CHEVROLET CAPRICE
  • 4.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 210,000 MILES
With the engine running for about forty minutes the heat gauge doesn't even make it to the middle, I was able to get some heat until I took it for a ride, about three miles it is blowing cold air. I changed the thermostat again because I thought I bought a bad one. I flushed heater core, the radiator and cleaned out fill tank and still nothing changed.
Tuesday, February 16th, 2016 AT 1:04 PM

9 Replies

Tiny
JOHNNYT73
  • MECHANIC
  • 924 POSTS
First check to make sure you have the thermostat installed facing the correct direction. Are you sure that your burped all the air out of the system? Was the coolant full of rust? If it was then you may want to check your water pump to see if the fins have rusted away.
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Tuesday, February 16th, 2016 AT 1:17 PM
Tiny
DAVE MACE
  • MEMBER
  • 6 POSTS
I installed a new water pump, thermostat and flushed about three months ago. I just changed thermostat and flushed again. I cleaned the hoses and flushed the heater core seperatley. I got the whole radiator covered with cardboard and it still runs just a bit above cold.
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Tuesday, February 16th, 2016 AT 1:39 PM
Tiny
DAVE MACE
  • MEMBER
  • 6 POSTS
My heater hoses are about 143 to 147 degrees just sitting at idle for forty minutes.
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Tuesday, February 16th, 2016 AT 1:42 PM
Tiny
JOHNNYT73
  • MECHANIC
  • 924 POSTS
I am willing to bet there is still air in the system. It is really the only option left (unless you have blend door issue). Start the engine and turn on the heat, let it idle until you think it is where it should be warmed up, raise the rpm to 2500 and hold for about 5 seconds (you may need to do this quite a bit), keep looking for bubble at the filler until they are gone and you have heat at idle, both radiator hoses should also feel hot.
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Tuesday, February 16th, 2016 AT 1:54 PM
Tiny
DAVE MACE
  • MEMBER
  • 6 POSTS
I burped the system for about three hours two days ago and I drove it to work twice for a total of 112 miles and the coolant level is fine I did not need to add any. It is difficult to get all the air out, but I am sure I got it.
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Tuesday, February 16th, 2016 AT 2:03 PM
Tiny
DAVE MACE
  • MEMBER
  • 6 POSTS
I can hold my hand on both hoses.
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Tuesday, February 16th, 2016 AT 2:06 PM
Tiny
CAR-MAN145
  • MECHANIC
  • 321 POSTS
Check to see how hot it is at both sides of the thermostat, if it is only about 140 degrees on both sides it is either the thermostat or it has an bypass problem.
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Thursday, February 18th, 2016 AT 12:36 AM
Tiny
DAVE MACE
  • MEMBER
  • 6 POSTS
Thanks, I will check it and get back to you.
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Tuesday, February 23rd, 2016 AT 3:52 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,149 POSTS
Please let us know what you find :-)
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Monday, March 7th, 2016 AT 1:39 PM

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