Heater core replacement

I attached the procedure for the heater core. Let us know if you need any more info. Thanks

Thanks man I appreciate it .

Anytime. Please come back to 2CarPros if you need anything else in the future. Thanks

Need step by step Instructions on how to replace a heater core in 2003 GMC Sonoma

Heater Core Replacement

Removal Procedure
Remove the heater/vent module. See: Housing Assembly HVAC\Service and Repair

Remove the heater core access cover screws.
Remove the heater core access cover.
Remove the heater core from the heater/vent module.
Installation Procedure

Install the heater core to the heater/vent module.

Install the heater core access cover.
NOTE: Refer to Fastener Notice in Service Precautions. See: Service Precautions\Vehicle Damage Warnings

Tighten
Tighten the heater core access cover screws to 1.9 N.m (17 lb in) .
Install the heater/vent module.

my heater will not warm uo if fact the system continues to blow cold air when i have the lever on hot. where is the heater core located? is it hard to get to?

Under the dash on the passenger side. Yes it is hard to get to. Try having it backflushed, the Dexcool the factory uses tends to plug them up causing low/no coolant flow

is a "backflush" the same thing as a radiator flush that the express oil change places offer? will i lose my new collent if that does not solve the problem and i need to have my core replaced?

does the fact i still get "cold refrigirated air" when i turn the knob to heat shed any light on the problem?

Yes it is the same thing.With engine hot, check both heater hoses to see i they are hot, if not there is a flow problem with thecore. You can remove the shields under the dash and locate the blend door actuator to see if it is moving when you select different temps

It's likely your heater core plugged. Flush it out. Mine had little reddish rust coloured chunks plugging it---thanks to GM's wonderful Dexcool. I run the good old fashioned Prestone green coolant....against the advice of GM of course. In any case, disconnect the inlet and outlet tubes on the firewall that goo to your heater core and flush it out with a garden hose. Simple.

You should be careful how much pressure is applied to the heater core with the hose, they dont like household pressure for very long

Absolutely.....be moderate with the water pressure applied-I was going to mention that but thought it was understood.

im a toyota mechanic and ofcourse my truck has a problem im not familiar with. i have a 2002 gmc sonoma v-6. there is gray coolant smoke blowing out of the vents inside the cab. ive diagnosed that it is a heater core going bad. i just want to know the procedure and where to start for removal. whether i can just get a way with pulling the glove box down or if i have to pull the whole dash apart.

1. Remove the instrument panel. Refer to Instrument Panel (I/P) Carrier Replacement in Instrument Panel, Gages and Console. 2. Drain the engine coolant. Refer to Draining and Filling Cooling System in Engine Cooling. 3. Remove the blower motor resistor. Refer to Blower Motor Resistor Assembly Replacement. Important :Mark and use the same mounting bolt for the heater/vent module during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door. 4. Remove the heat/vent module mounting bolt through the blower motor resistor or service access cover opening. 5. Remove the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End. 6. Remove the front right tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels. 7. On the Utility only, remove the A/C evaporator and blower module heat shield screws. 8. On the Utility only, slide the A/C evaporator and blower module heat shield toward the front of the vehicle. 9. Remove the 2 lower heat/vent module mounting nuts. 10. On the Utility only, remove the A/C evaporator and blower module heat shield bracket. 11. Remove the bottom right heat/vent module mounting bolt from inside the vehicle. Important :The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module. 12. On the Utility only, while an assistant inside the vehicle pulls the bottom right corner of the heat/vent module approximately 2.5 mm (1 in) back, remove the 2 heat/vent module mounting studs. 13. Lower the vehicle. 14. On vehicles with a 2.2 L engine only, remove the engine wiring harness bracket located at the rear of the intake manifold. Refer to Valve Rocker Arm Cover Replacement in Engine Mechanical - 2.2 L. 15. Remove the HVAC module mounting bolt located at the lower left side of the heater core to heater hose connection. 16. Remove the HVAC module mounting nut located at the lower right side of the heater core to heater connection. Important :The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module. 17. On the Utility only, loosen the HVAC module mounting studs until the threads are free from the heat/vent module. 18. Disconnect all of the electrical connectors from the HVAC module. 19. Disconnect all of the vacuum lines from the heater assembly. 20. Disconnect the heater hoses from the heater core. 21. Remove the HVAC module from the vehicle. have to remove the dash first,not to bad to do.just 6 bolts across the top of the dash and 2 under both speaker covers,3 bulk head connectors under the dash and remove the radio and IPC.outside remove the R/F wheel and fender well,remove the bracket on the firewall and remove the blower resistor,there is a hidden 10mm bolt.not to bad to do,used to do these in about 1 hour,made a living off these at the GM dealer.

How much will it cost to replace radiator, heater core and head gasket? 2.2 liter

heater core

Part OEM Part Price
Heater Core
Main Heater
Heater Core 52473178 $165.10
Contact dealer for most current part and price information.

Labor Skill
Level Mfg.
Warranty Standard
Heater Core
Replace
Main Heater
Without AC B 3.3 8.3
With AC B 4.1 8.9
NOTE
With Floor Shift, Add B 0.2 0.3

radiator

Part OEM Part Price
Radiator
Radiator
1 - Manual Trans 89040307 $337.83
1 - Auto Trans 89040307 $337.83

Labor Skill
Level Mfg.
Warranty Standard
Radiator
Replace C 0.9 1.4
NOTE
With Auto Trans, Add C 0.1 0.2
With Oil Cooler, Add C 0.1 0.2


head gasket

Labor Skill
Level Mfg.
Warranty Standard
Cylinder Head Assembly
Replace B 5.2 7.5
Includes: R&R Cylinder Head, Grind Or Renew Valves, Transfer All Necessary Components & Make All Adjustments.
NOTE
With AC, Add B 0.2 0.4

gasket, fluids around 125.


Roy

I have noticed while driving I can smell antifreeze. Its not over heating. Its maintaining 180 degrees and no leaks that I can tell. Could it possibly be a heater core leak?.

Place the heater setting on defrost does it fog the windshield and if it does then its a good chance that the heater core is leaking
check under hood around the intake manifold and hoses
coolant system pressure test should reveal the leak
check idle air control valve (clean and or replace )

enter your question.I DON'T HAVE ANY HEAT,I replaced the therm.and all ..switches seem to be working. there dosen't seem to be any water circulating thru heater core. The engin isn't overheating. Could this still be the water pump.

Does it run at operating temp ?
Run engine and check heater hoses by the fire wall if both hot and no hot air inside
problem is in the heater box and blend door or blend door actuator

Also check if it has a heater control valve

The engin runs at operating temp. The inlet hose gets warm, but not hot and the exit hose stays cool. It is like there isn't enought pressure in the line. Does the blend box stop the flow of the water.

They do not use a valve in this system and blend system was used
as they direct the air thro and over the heater core and or the AC system and fresh air

heater core need to be isolated and flushed

I did that and water runs thru it freely.

If water running thru freely and no heat on the inside ,engine reaching operating temp ,
check blend door operation and i would suspect the actuator on the door

When I say water is rinning freely, It is with the hoses disconnected. How do I get to the actuator.

under the dash on the heater box
i will try to find a picture for you

Thanks

this a picture of the part and what it look like
let me know

OK, I will have to go take a look at it. I probably won't get to it until tomorrow. Thanks for your help.

good luck
let me know

Heater problem
1998 GMC Sonoma 4 cyl Two Wheel Drive Automatic

My heater is barely working I changed the thermostat. How do i tell if it is the cable or the heater core is plugged?

Hi Trafficflow,

Thank you for the donation.

Note the cable position at valve at fully opened and fully closed position.
Disconnect the cable and check the valve operations manually.

Operate the valve manually and compare the fully opened and closed position. If there are any difference, readjust the cable and retest.

If no difference, fullly open the valve and with engine running, compare the heat of both hoses, they should be similar if coolant is flowing through.

Did you recheck the coolant level after the thermostat replacement? Any air trapped in system can cause the heater to work erratically.

Another possible cause would be the air mix door.

To test if the heater core is clogged, disconnect both hoses and use a water hose to flush through. If water flows freely, it should be good.

Good Info. Can you send a picture of where it is?
I have no idea where it is or how to get to it. Thanks

I am unable to find any clear diagrams for the heater valve and other items from our database. The heater valve should be in engine compartment near the heater core hoses.

Just before we proceed further, I would like to know the following.

What is the actual problem that your are facing? No heat with blowers functioning correctly?

Are all the various vents selection working correctly?

The vents and air mix are activated by vacumn and if they are not functioning correctly, it could be a clogged or leaking vacumn line.

I do not think it is a air issuer. The blower works and when I change the vent from floor to dash works. It is just barely getting warm. Thanks

As the vents are working correctly, the issue shoudl not be from the vacumn.

Check the heater hose and valve near the firewall.

I checked the heater core and there is no blockage ?? Air lock possible Water Pump??
I do not see no valve on either line If it is in the dash why is the hoses not getting warm?

Okay this is what I have
I checked the heater not clogged
Changed thermostat
Heater dioor moves to direct from defrost to floor
Cold to warm switch works it getts real ood when i move
No heater valve in cooling at all I checked
This is what woeks .
When i leave fan on low there is actually some heat coming out the lower vent, I will check for air block but I had the heater core lines of .
What do you reallly think it could be ???Thanks

where are all the bolts to remove dash pad enough to replace heater core can heater core be repaired with solder if its a pin hole i appreciate the info THANX