Coolant leak outside truck directly below heater core

Tiny
JRIEGERT
  • MEMBER
  • 2001 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 154,000 MILES
I just got done replacing my water pump, thermostat and it's housing and both belts. Also had to have some else replace my freeze plugs, though I'm not 100% sure they replaced them all.
I still have a small leak coming from what appears to be directly under the heater core, but not inside the truck, outside. It will leak out about 1 gallon of coolant every 4 miles. It won't leak cold and with the truck off, but as soon as I start driving it, it starts loosing coolant. I also have radiator vapors coming through my heater vents, whether the heater is off or on, or even set on A/C. Is it my heater core, like I think? Or could it be something else?
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Friday, November 29th, 2019 AT 10:20 AM

6 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good afternoon,

It sounds like the heater core is leaking. The coolant is coming from the AC drain hole in the evaporator. Common issue.

I would replace the heater core.

https://www.2carpros.com/articles/replace-heater-core

Roy
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Friday, November 29th, 2019 AT 11:27 AM
Tiny
ASEMASTER6371
  • EXPERT
I attached a you tube video for you of the replacement.

Roy

https://www.youtube.com/watch?v=4OWbSgPCTkE
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Friday, November 29th, 2019 AT 11:30 AM
Tiny
JRIEGERT
  • MEMBER
Thank you, then it's what I was thinking. Just wasn't 100% sure because it wasn't leaking inside the cab, like it did when my heater core went out in my 1982 Firebird.
In your opinion, would linking those hoses together to bypass the heater core until I can get it fixed cause any issues, especially with everything I've replaced and had others replace?
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Friday, November 29th, 2019 AT 11:34 AM
Tiny
ASEMASTER6371
  • EXPERT
No, that is a good temporary fix until you get it repaired.

Roy
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Friday, November 29th, 2019 AT 11:55 AM
Tiny
JRIEGERT
  • MEMBER
Thank you very much.
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Friday, November 29th, 2019 AT 12:36 PM
Tiny
ASEMASTER6371
  • EXPERT
You are welcome.

Always glad to help.

Roy
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Friday, November 29th, 2019 AT 12:40 PM

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