Heater core?

Tiny
ITSRONDO
  • MEMBER
  • 2004 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 10,000 MILES
How do I remove the heater core?
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Thursday, June 10th, 2010 AT 9:46 PM

50 Replies

Tiny
BLUELIGHTNIN6
  • MECHANIC
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Hello,

Start by disconnecting the battery and you will need to vacuum the AC system and drain the coolant out. Here is a guide that will help and the instructions for doing the job are in the diagrams below.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

and this is an older truck but you get the idea, check the diagrams below to replace the heater core in your truck.

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

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Thursday, June 10th, 2010 AT 9:56 PM
Tiny
TIGERPAW
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  • 1 POST
  • 2003 CHEVROLET BLAZER
Heater problem
2003 Chevy Blazer 6 cyl Two Wheel Drive Manual 64.000 miles

I have replaced my thermostste still no heat. Doesnot get to the half way hot sometimes I have a film of somekind on my windshield sometime I leak coolent but not much. One person says I need a heater core another says a head gasket it doesnot give off any heat at all I dont have a couple of hundred bucks to play arround with both jobs are very extensive so I am told are they right
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Wednesday, August 19th, 2020 AT 8:08 PM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
Symptoms fit a heat core not a head gasket.

The film on the window is probably the anti-freeze from a slow leak in the core. IF the core is not staying full, there will be no heat.

Do you know where the coolant leak is you mentioned?
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Wednesday, August 19th, 2020 AT 8:08 PM (Merged)
Tiny
AFISHERMA
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET BLAZER
  • V8
  • 4WD
  • AUTOMATIC
  • 90,000 MILES
The I think the heater went out. It is blowing cold air. Fisrt I started noticing that while idleing the air turned from hot to cold, and then while accelerating the air turned back to warm, but now it does not get warm at all even when accelerating, is this the heating element, the heater core, or would this be a thermostat issue? I know it is not a blower issue because it still kicks out a great deal of air, its just cold even after the vehicle is completely warmed up.
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Wednesday, August 19th, 2020 AT 8:09 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
It could be a thermostat or the heater core is plugged and needs prestones super flush. This is the only flushing kit I found that works for the blazer heater core
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Wednesday, August 19th, 2020 AT 8:09 PM (Merged)
Tiny
GUNNYSARGE
  • MEMBER
  • 3 POSTS
  • 2002 CHEVROLET BLAZER
  • V12
  • 4WD
  • AUTOMATIC
  • 88,410 MILES
Wife say no heat. I pulled the hoses from the heater core on the fire wall. No water on one side. Can I flush or blow air thru core or do I have to replace?
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
OBXAUTOMEDIC
  • MECHANIC
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Hello,

You can try flushing with water, from the no water side, and see if can flush it out.

And of course if can't then will need to replace.

.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
CARLOS_GONZALEZ_JR
  • MEMBER
  • 1 POST
  • 2002 CHEVROLET BLAZER
Heater problem
2002 Chevy Blazer 6 cyl Two Wheel Drive Automatic

What is the process of heater core replacement
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
REMOVAL:
Remove the HVAC module-auxiliary.
Remove the screws from heater core cover-auxiliary from the HVAC module-auxiliary.
Remove the heater core cover-auxiliary.
Remove the HVAC module pass thru seal-auxiliary.
Remove the heater core-auxiliary from the HVAC module-auxiliary.

INSTALLATION:
Install the heater core-auxiliary to the HVAC module-auxiliary.
Install the HVAC module pass thru seal-auxiliary.
Install the heater core access cover-auxiliary to the HVAC module-auxiliary.
Install the screws to the heater core access cover-auxiliary and tighten to 18 inch lbs. (2 Nm).
Install the HVAC module-auxiliary.

HVAC MODULE REMOVAL/INSTALLATION:
Recover the refrigerant.
Drain the cooling system.
Raise and support the vehicle.
Remove the nuts from rear A/C line block fittings.
NOTE
Cap or tape the open A/C refrigerant lines immediately.

Remove the A/C line block fittings and discard the O-ring seals.
Remove the nuts from the heater hoses block fittings.
Remove the heater hoses block fittings from the HVAC module-auxiliary.
Remove the nuts from the HVAC module studs.
Lower the vehicle.
Remove the right side rear quarter trim.
Disconnect the electrical connectors from the HVAC module.
Disconnect the rear compartment air outlet ducts from the HVAC module.
Remove the mounting bolts from the HVAC module.
Remove the HVAC module.
Remove and discard the HVAC module pass through seal.

To install:
Install new HVAC module pass through seal.
Install the HVAC module.
Install the HVAC module mounting bolts and tighten to 89 inch lbs. (10 Nm).
Install the air outlet ducts.
Connect the electrical connectors.
Install the right side rear quarter trim panel.
Raise and support the vehicle.
Connect the heater hoses to the heater core.
Install the nuts to the HVAC module studs. Tighten the nuts to 89 inch lbs. (10 Nm).
Remove the cap or tape from the A/C lines.
Install the new O-ring seals.
Install the nuts to the evaporator core studs and tighten to 15 ft. Lbs. (20 Nm).
Lower the vehicle.
Fill the cooling system.
Evacuate and charge the system.
Leak test the fitting of the component.

Thanks for using 2CarPros. Com!
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
CHUCK PUGH
  • MEMBER
  • 1 POST
  • 2002 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 97,523 MILES
How do I know if my heater core is going bad? The guages are all reading their normal reading, but I have water coming from what looks like the heater core area. When the heat is on all I'm getting is cold air, but the vehicle is not over heating. The last time I replaced a heater core there was water in the passenger floor board. Not this time. I'm stumped.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
BLUELIGHTNIN6
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May be faulty heater core hose that is leaking outside of cab so no coolant getting into floorboard. If coolant is found leaking around core then either hoses or core is faulty.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
2CP-ARCHIVES
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  • 2002 CHEVROLET BLAZER
  • 82,000 MILES
Greetings, I just had my heater core replaced. All air functions including a/c/ work except that there is no air switching over from cold to hot. Not sure where to go from here. Thnx.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
HMAC300
  • MECHANIC
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Take it back and have them check to see if all the actuators are working, bet they aren't. Probably forgot to hook it up or not all the way so it won't work.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
ZIGGY61
  • MEMBER
  • 5 POSTS
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 125,000 MILES
Which is the heater core intake hose
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
BLACKOP555
  • MECHANIC
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That doesnt matter. Unless you have a heater control valve and thats on the intake line.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
But if you really want to know you can find th ehotter hose and that will be the intake to the heater core.
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
REDNECKHOSPITALITY
  • MEMBER
  • 1 POST
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 181,026 MILES
Whats the best route to fix or can I bypass it. Its the heater core
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Wednesday, August 19th, 2020 AT 8:10 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
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It is simpler to bypass it but then heater would not work. Is best just to replace so it will work properly.
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Wednesday, August 19th, 2020 AT 8:11 PM (Merged)
Tiny
MARK52010
  • MEMBER
  • 3 POSTS
I own a 99 Chevy Blazer and my heater core also just started leaking on me. For now I just removed the two hoses from the heater cores inlet and outlet under the hood of the car on the firewall. I took a 3/8" X 2" piece of pipe and connected the two hoses together with hose clamps. That will bypass the heater core and you will still be able to drive your vehicle without the interior of the vehicle steaming up, smelling or leaking onto the carpeting. You can by a new heater core for about $65.00 for a Delphi that comes with a lifetime warranty. I bought a repair manual from a local auto parts store for Chevy Pickup Trucks, Blazers, and Jimmys. It explains exactly which screws and bolts to remove so you will be able to replace the heater core. If you are very handy and can take apart your dashboard then you may want to attempt to replace it yourself. I have checked around and got prices between $700-$950! I was thinking of attempting to do it myself but since the weather has gotten warmer I don't need heat right now so I have put it off until it starts to get colder. Also you must be very carefull if you do attempt to take apart your dashboard not to disturb any of the air bags sensors that are located in the dashboard. Get the manual and follow the instructions and you can replace the heater core for less than $100! Good luck!
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Wednesday, August 19th, 2020 AT 8:11 PM (Merged)
Tiny
MICAMIL
  • MEMBER
  • 1 POST
  • 2001 CHEVROLET BLAZER
Heater problem
2001 Chevy Blazer V8 Four Wheel Drive Automatic

have the dashboard out put there is a mounting unit around the heater core that I can not get off.
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Wednesday, August 19th, 2020 AT 8:11 PM (Merged)

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