• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Heater Core Replacement

Explicit_Spade

Perma-Banned! JK LOL
Here's a little writeup on replacing the heater core in a 2004+ Grand Prix, information provided is from a 2004 GT, if there are any differences noted in any other year or trim, Post or PM me and changes will be made accordingly.


Technical Service Bulletins
INFORMATION

Bulletin No.: 05-06-02-001A

Date: July 16, 2008

Subject:
Information On Aluminum Heater Core and/or Radiator Replacement

Models:
2005 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn)
2003-2005 HUMMER H2

Supercede:

This bulletin is being revised to update the Warranty Information. Please discard Corporate Bulletin Number 05-06-02-001 (Section 06 - Engine/Propulsion System).

Important: 2004-05 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX-COOL(R). Refer to the flushing procedure explained later in this bulletin.

The following information should be utilized when servicing aluminum heater core and/or radiators on repeat visits. A replacement may be necessary because erosion, corrosion, or insufficient inhibitor levels may cause damage to the heater core, radiator or water pump. A coolant check should be performed whenever a heater core, radiator, or water pump is replaced. The following procedures/ inspections should be done to verify proper coolant effectiveness.

Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if the radiator cap or surge tank cap is removed while the engine and radiator are still hot.

Important: If the vehicle's coolant is low, drained out, or the customer has repeatedly added coolant or water to the system, then the system should be completely flushed using the procedure explained later in this bulletin.

Technician Diagnosis

^ Verify coolant concentration. A 50% coolant/water solution ensures proper freeze and corrosion protection. Inhibitor levels cannot be easily measured in the field, but can be indirectly done by the measurement of coolant concentration. This must be done by using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale), or equivalent, coolant tester. The Refractometer uses a minimal amount of coolant that can be taken from the coolant recovery reservoir, radiator or the engine block. Inexpensive gravity float testers (floating balls) will not completely analyze the coolant concentration fully and should not be used. The concentration levels should be between 50% and 65% coolant concentrate. This mixture will have a freeze point protection of -34 degrees Fahrenheit (-37 degrees Celsius). If the concentration is below 50%, the cooling system must be flushed.

^ Inspect the coolant flow restrictor if the vehicle is equipped with one. Refer to Service Information (SI) and/or the appropriate Service Manual for component location and condition for operation.

^ Verify that no electrolysis is present in the cooling system. This electrolysis test can be performed before or after the system has been repaired. Use a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory and can be verified by watching the volt meter and turning on and off various accessories or engage the starter motor. Before using one of the following flush procedures, the coolant recovery reservoir must be removed, drained, cleaned and reinstalled before refilling the system.

Notice: ^ Using coolant other than DEX‐COOL(R) may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50,000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX‐COOL(R) (silicate free) coolant in your vehicle.

^ If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts.


Flushing Procedures using DEX-COOL(R)

Important: The following procedure recommends refilling the system with DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. This coolant is orange in color and has a service interval of 5 years or 240,000 km (150,000 mi). However, when used on vehicles built prior to the introduction of DEX-COOL(R), maintenance intervals will remain the same as specified in the Owner's Manual.

^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions.

^ If approved cooling system flush and fill machine is not available, drain the coolant and dispose of properly following the draining procedures in the appropriate Service Manual. Refill the system using clear, drinkable water and run the vehicle until the thermostat opens. Repeat and run the vehicle three (3) times to totally remove the old coolant or until the drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with DEX‐COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M, following the refill procedures in the appropriate Service Manual.


If a Service Manual is not available, fill half the capacity of the system with 100% DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. Then slowly add clear, drinkable water (preferably distilled) to the system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and reverify the coolant level. If necessary, add clean water to restore the coolant to the appropriate level.

Once the system is refilled, reverify the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. The concentration levels should be between 50% and 65%.

Flushing Procedures using Conventional Silicated (Green Colored) Coolant

Important: 2004-2005 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX‐COOL(R). The Aveo and Wave are filled with conventional, silicated engine coolant that is blue in color. Silicated coolants are typically green in color and are required to be drained, flushed and refilled every 30,000 miles (48,000 km). The Aveo and Wave are to be serviced with conventional, silicated coolant. Use P/N 12378560 (1 gal) (in Canada, use P/N 88862159 (1 L). Refer to the Owner's Manual or Service Information (SI) for further information on OEM coolant.

Important: Do not mix the OEM orange colored DEX-COOL(R) coolant with green colored coolant when adding coolant to the system or when servicing the vehicle's cooling system. Mixing the orange and green colored coolants will produce a brown coolant which may be a customer dissatisfier and will not extend the service interval to that of DEX-COOL(R). Conventional silicated coolants offered by GM Service and Parts Operations are green in color.

^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions.

^ If approved cooling systems flush and fill machine is not available, drain coolant and dispose of properly following the draining procedures in appropriate Service Manual. Refill the system using clear, drinkable water and run vehicle until thermostat opens. Repeat and run vehicle three (3) times to totally remove old coolant or until drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with a good quality ethylene glycol base engine coolant, P/N 12378560, 1 gal (in Canada, use P/N 88862159 1 L), conforming to GM specification 1825M, or recycled coolant conforming to GM specification 1825M, following the refill procedures in the appropriate Service Manual.


If a Service Manual is not available, fill half the capacity of the system with 100% good quality ethylene glycol base (green colored) engine coolant, P/N 12378560 1 gal., (in Canada, use P/N 88862159 1 L) conforming to GM specification 1825M. Then slowly add clear, drinkable water (preferably distilled) to system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and recheck coolant level. If necessary, add clean water to restore coolant to the appropriate level.

Once the system is refilled, recheck the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. Concentration levels should be between 50% and 65%.

41210227.gif


12734644.gif


86369804.gif



Parts Information
Heater Core
Part# 89018289
Price $203.40
Contact dealer for most current part and price information.

Labor Information
Heater Core Replace
Skill: B
Warranty: 2.0
Normal: 2.7

With Center Console, Add
Skill: B
Warranty: 0.6
Normal: 0.8

Heater Case/Cover Replacement
Removal Procedure


29055262.gif


1.Remove the RH Instrument Panel Closeout/Insulator panel.
2.Remove the LH Instrument Panel Closeout/Insulator panel.
3.Remove the floor carpet.
4.Remove the rear floor air outlet duct from the holes in the floor reinforcement.
5.Disconnect the rear floor air outlet duct from the heater air outlet cover.
6.Remove the rear floor air outlet duct.
7.Remove the heater air outlet cover screws (2).
8.Remove the heater air outlet cover heat stakes (1) with a small chisel.
9.Remove the heater air outlet cover from the HVAC module assembly.

55748838.gif


10.Remove the heater core cover screws (2).
11.Remove the heater core cover heat stakes (1) with a small chisel.
12.Remove the heater core cover from the HVAC module assembly.





INSTALLATION PROCEDURE


55748838.gif


1.From the inside of the heater core cover, drill the dimples adjacent to the heat stakes using a 5.5 mm (7/32 in) drill bit.
2.Install the heater core cover to the HVAC module assembly. NOTE: Refer to Fastener Notice in Service Precautions.
3.Install the heater core cover screws (2). Tighten Tighten all screws to 1.5 N.m (13 lb in) .
4.From the inside of the heater air outlet cover, drill the dimples adjacent to the heat stakes using a 5.5 N.m (7/32 in) drill bit.

29055262.gif


5.Install the heater air outlet cover.
6.Install the heater air outlet cover screws (2) Tighten Tighten the screws to 1.5 N.m (13 lb in) .
7.Connect the rear floor air outlet duct to the heater air outlet cover.
8.Install the rear floor air outlet duct to the holes in the floor reinforcement.
9.Install the floor carpet.
10.Install the RH Instrument Panel Closeout/Insulator panel.
11.Install the LH Instrument Panel Closeout/Insulator panel.



Heater Core Replacement
TOOLS REQUIRED
J 38185 Hose Clamp Pliers

REMOVAL PROCEDURE

19660009.gif


1.Drain the coolant. Refer to Draining and Filling Cooling System in Cooling System.
2.Use J 38185 in order to position aside the heater hose inlet and outlet clamps at the heater core.
3.Disconnect the inlet and outlet heater hose from the heater core.
4.Remove the RH Instrument Panel Closeout/Insulator panel.
5.Remove the LH Instrument Panel Closeout/insulator panel.
6.Remove the floor carpet.
7.Remove the rear floor air outlet duct from the holes in the floor reinforcement.
8.Disconnect the rear floor air outlet duct from the heater core outlet cover.
9.Remove the rear floor air outlet duct.

10440098.gif


10.Remove the heater core outlet cover screws (2).
11.Remove the heater core outlet cover heat stakes (1) with a small chisel.
12.Remove the heater core outlet cover from the HVAC module assembly.

55748838.gif


13.Remove the heater core cover screws (2).
14.Remove the heater core cover heat stakes (1) with a small chisel.
15.Remove the heater core cover from the HVAC module assembly.

67135030.gif


16.Remove the heater core from the HVAC module assembly.

33155085.gif



17.Remove the heater core foam seal (1) from the HVAC module assembly.


Installation Procedure

33155085.gif


1.Install a new heater core foam seal (1) to the HVAC module assembly.
2.Install the heater core to the HVAC module assembly.
3.From the inside of the heater core cover, drill the dimples adjacent to the heat stakes using a 5.5 mm (7/32 in) drill bit.

55748838.gif


4.Install the heater core cover. NOTE: Refer to Fastener Notice in Service Precautions.
5.Install the heater core cover screws to the heater core cover. Tighten Tighten all the screws to 1.5 N.m (13 lb in) .
6.From the inside of the heater core outlet cover, drill the dimples adjacent to the heat stakes using a 5.5 mm (7/32 in) drill bit.

10440098.gif


7.Install the heater core outlet cover.
8.Install the heater core outlet cover screws (2). Tighten Tighten the screws to 1.5 N.m (13 lb in) .
9.Connect the rear floor air outlet duct to the heater core outlet cover.
10.Install the rear floor air outlet duct to the holes in the floor reinforcement.
11.Install the floor carpet.

19660009.gif


12.Install the RH Instrument Panel Closeout/Insulator panel.
13.Install the RH Instrument Panel Closeout/Insulator panel.
14.Connect the inlet and outlet heater hose to the heater core.
15.Use J38185 in order to reposition the heater hose inlet and outlet clamps to the heater core.
16.Refill the coolant. Refer to Draining and Filling Cooling System in Cooling System.
 
Last edited:


i dont get whats up with the "chisel stakes" thing, do ya really need to redrill holes???

YEP,,1/4 sharp wood chisel made popping the heads off a breeze. Then you drill out marked spot next to old stake position and use new #6 or #8 3/4" sheet metal screws to re-fasten shroud.

Once you look at it in the car it all falls into place. Looking at the GM repair right here made me dizzy.
 
I just did mine 2 months ago. Yes... you have to chisel out the small stakes... look like little round balls of plastic in place of where a screw would go. Some of them, i was able to use a drill. Others, you have to get a chisel and very uncomfortably break them out... its not fun.
 


Well im next on this list. Driving home and car started to overheat. Turned the heat on to make it home and felt my leg getting wet. Whole passanger floor covered in anti freeze. And it was spewing out of the duct. Yay me. Hopefully this wont be too bad....
 
Anybody have any advice for chiseling out the stakes? I can't even get a chisel on a couple of them? did anybody cut them off with a dremel or the like? or drill them out? I really don't want to pay $700 to have this fixed.
 


Anybody have any advice for chiseling out the stakes? I can't even get a chisel on a couple of them? did anybody cut them off with a dremel or the like? or drill them out? I really don't want to pay $700 to have this fixed.
I used a sharp 1/4" wood chisel, pushed and worked it back and forth. They come out really easy.
If they are in a hard to reach spot, tap it with a pliers.
 
Hi, the 1/4 chisel took the #1 covers off the stakes. I see the posts next to each #1, labeled #2 screws, but don't see any screws. Are they under the plastic? Do they get chiselled off also?
 
There is nothing behind the plastic stakes. Once you chisel the head off, that is it. The screws are all obviously screws. Just need to find all of them. It's either a screw or a little bead of plastic (the stakes).

I got rid of my GP a month or so ago so I can't get any pics for you. From what I remember, the screws were the easy ones to find. There was a stake that took me forever to find. I drilled most of them out but the last 2-3 I had to chisel. I know this isn't much help, but... It's all I got.
 
Hi, the 1/4 chisel took the #1 covers off the stakes. I see the posts next to each #1, labeled #2 screws, but don't see any screws. Are they under the plastic? Do they get chiselled off also?

Those are for when you put it back together. You will need #6 or #8 x 3/4 sheet metal screws to fasten it thru those spots since the stakes are gone to secure it.
Use a phillips head or hex head and shoot them in. They go in easy.
 


crap on a stick I'm doing this tomorrow

All I took out was the glovebox for a little more room....maybe the radio bezel.

Use a 1/4 inch socket set with long extensions....a universal is needed for the screws towards the firewall.
The inlet for the back heatduct Y will come out and go back in. I probably used a painters 4in1 for that, maybe with the 6" baby flat bar.
Hardest part for me was the hoses in the engine bay. Angle was messed up but a 8" pliers works, with the back and forth.
 
Do the front seats, carpet and center console REALLY need to be removed to get to the heater core?

Also whats the orientation of the above pictures from the official GM service manual?

Is it looking up as you are laying on the floor of the car?
 
the console "has" to come out, seats are up to you. as your the one on your back on the floor board. i took mine out, its extra room. and its only 2 bolts per seat, whats the big deal?
 
the console "has" to come out, seats are up to you. as your the one on your back on the floor board. i took mine out, its extra room. and its only 2 bolts per seat, whats the big deal?

Thanks for the clarification.

Just trying to read between the lines of all the previously mentioned comments/hints/tricks.
 
Back
Top