Shop Discount Heater Cores

That's the drain for the A/C condensation. Assuming it's cold where you are and that can't be condensation water from the A/C, it would have to be the coolant you have been looking for.

Nothing to figure out. It's very common to leak out there with a bad heater core. Where the coolant comes out is determined by the design of the housing and which direction the coolant runs.

Weird picture... Looks like a brake booster with heater hose connections coming out of it. Must be right hand drive.

Some good info, so you don't have a repeat failure:

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%.

Wow. Great info. This place is awesome. Thanks for your help. I'll make sure to use the right coolant next time. I've got a date with the dashboard this weekend.

Just be careful and don't blow your face off working around the air bag system. Your probably going to be working around zones 3 & 5, so disarm those zones before removing any components or working around their circuits after disconnecting the battery.



SIR SERVICE PRECAUTIONS

CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling Zones. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs.

The inflatable restraint sensing and diagnostic module (SDM) maintains a reserved energy supply. The reserved energy supply provides deployment power for the air bags. Deployment power is available for as much as 1 minute after disconnecting the vehicle power. Disabling the SIR system prevents deployment of the air bags from the reserved energy supply.


GENERAL SERVICE INSTRUCTIONS

The following are general service instructions which must be followed in order to properly repair the vehicle and return it to its original integrity:
- Do not expose inflator modules to temperatures above 65 °C (150 °F).
- Verify the correct replacement part number. Do not substitute a component from a different vehicle.
- Use only original GM replacement parts available from your authorized GM dealer. Do not use salvaged parts for repairs to the SIR system.

Discard any of the following components if it has been dropped from a height of 91 cm (3 ft) or greater:
- Inflatable restraint sensing and diagnostic module (SDM)
- Inflatable restraint I/P module
- Inflatable restraint steering wheel module
- Inflatable restraint steering wheel module coil
- Inflatable restraint roof rail modules
- Inflatable restraint sides (SIS)
- Inflatable restraint seat be pretensioners
- Inflatable restraint front end sensor.





Zone 3 disarm:

1. Turn the steering wheel so that the vehicles wheels are pointing straight ahead.
2. Turn the ignition switch to the OFF position.
3. Remove the key from the ignition switch.
4. Locate the body control module fuse center then remove the fuse center cover.

5. Locate and remove the AIR BAG fuse from the body control module fuse center.

IMPORTANT: With the AIR BAG fuse removed and the ignition switch in the ON position, the AIR BAG warning indicator illuminates. This is normal operation, and does not indicate an SIR system malfunction.

6. Remove the connector position assurance (CPA) from the steering wheel module coil connector.

7. Disconnect the steering wheel module coil connector from the vehicle harness connector.

ENABLING PROCEDURE
1. Remove the key from the ignition switch.

2. Connect the steering wheel module coil connector to the vehicle harness connector.
3. Install the CPA to the steering wheel module coil connector.

4. Install the AIR BAG fuse into the body control module fuse center.
5. Install the body control module fuse center cover.
6. Use caution while reaching in and turn the ignition switch to the ON position.The AIR BAG indicator will flash then turn OFF.
7. Perform the SIR Diagnostic System Check if the AIR BAG warning indicator does not operate as described. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information.

Zone 5 disarm:


SIR DISABLING AND ENABLING ZONE 5

DISABLING PROCEDURE
1. Turn the steering wheel so that the vehicles wheels are pointing straight ahead.
2. Turn the ignition switch to the OFF position.
3. Remove the key from the ignition switch.
4. Locate the body control module fuse center, then remove the fuse center cover.

5. Locate and remove the AIR BAG fuse from the body control module fuse center.

IMPORTANT: With the AIR BAG fuse removed and the ignition switch in the ON position, the AIR BAG warning indicator illuminates. This is normal operation, and does not indicate an SIR system malfunction.

6. Remove the connector position assurance (CPA) from the I/P module connector.
7. Disconnect the I/P module connector from the vehicle harness connector.

ENABLING PROCEDURE
1. Remove the key from the ignition switch.

2. Connect the I/P module connector to the vehicle harness connector.
3. Install the CPA to the I/P module connector.

4. Install the AIR BAG fuse into the body control module fuse center.
5. Install the body control module fuse center cover.
6. Use caution while reaching in and turn the ignition switch to the ON position.The AIR BAG indicator will flash then turn OFF.
7. Perform the SIR Diagnostic System Check if the AIR BAG warning indicator does not operate as described. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information.

Thanks Discretesignals. I will definitely be careful. You may have saved my face. :)

The order of the hoses doesn't matter. As long as the coolant flows through it you will have heat. When you take the line coupler apart, the hoses should bend towards the appropriate pipe they were originally connected to. But, like I said, it's bidirectional.

Steve

Basically look at the heater hoses. That's the heater core. Everything in its way needs to be removed and replaced exactly. If you (shouldn't) have air bags this can be dangerous. DanD may be by with some neat pics or diagrams. If you are still driving this, take the smaller rubber gasket off the radiator cap and cut it like a pie slice out of it and system won't pump anti-freeze or slow it way down till you get to this. Of course you will need a new radiator cap later. - T

I had a 77 LTD that you could change a heater core faster that an easy thermostat. I don't know why some are made to be so difficult but some are a nightmare! - T