A/C - Reduced Heater Output At Idle
TSB 08-22-311/10/08
3.5L - REDUCED HEATER DUCT DISCHARGE
TEMPERATURE AT IDLE - BUILT ON OR BEFORE
5/31/2008
LINCOLN:
2008 MKZ
This article supersedes TSB 08-6-6 to add a production fix date, update the Service Procedure and Part List.
ISSUE
Some 2008 Lincoln MKZ vehicles equipped with a 3.5L engine and built on or before 5/31/2008 may exhibit a customer concern of reduced heater duct discharge temperature when the vehicle engine is brought down to an idle speed.
ACTION
Follow the Service Procedure steps to correct the condition.
SERVICE PROCEDURE
Verify Concern
1. Idle the engine at an ambient of 60 °F (15 °C) or higher until the engine is fully warmed up.
2. Set the control head to 90 °F (32 °C).
3. Set the mode to panel/vent and ensure A/C is switched-off.
4. Set the blower to highest speed. Idle the engine for 5 minutes with the hood down. The left-center vent discharge air temperature should be a minimum of 150 °F (65 °C).
5. If heater performance is met, return the vehicle to the customer and do not continue with this procedure. If the heater performance is not met, proceed to Cooling System Flush procedure.
Cooling System Flush
1. Drain coolant using Workshop Manual (WSM), Section 303-03.
2. Remove battery, using WSM, Section 414-01, to gain access to thermostat housing.
3. Check the engines built date.
NOTE
THE ENGINE BUILD DATE IS ON THE ENGINE CODE TAG LOCATED ON THE FRONT COVER OR THE RIGHT HAND CAM COVER. THE DATE IS LOCATED IN THE CENTER OF THE TAG IN A DATE/MONTH/YEAR SEQUENCE.
a. If the engine's built date is on or before 4/1/2008, proceed to Step 4.
b. If the engine built date is after 4/1/2008 disconnect the heater hoses at this time, and proceed to Step 7.
4. Remove the thermostat housing per WSM, Sections 303-03 and replace Water Pump Inlet Tube. (Figure 1)
NOTE
PRIOR TO PULLING AND REMOVING THE WATER PUMP INLET TUBE FROM THE WATER PUMP OUTLET HOLE, REMOVE ANY LEFT OVER FLUID INSIDE THE INLET TUBE USING A SUCTION GUN OR EQUIVALENT. THIS WILL PREVENT ANY COOLANT FROM COLLECTING IN THE ENGINE VALLEY.
5. Lubricate the new 0-ring seals with clean engine coolant.
6. Install the thermostat housing per WSM, Section 303-03 except do not connect the heater hoses at this time.
7. Back flush heater core through heater return hose with tap water for 2 minutes.
8. Attach a drain hose to heater return port on thermostat housing to prevent coolant from splashing and staining the engine compartment.
9. Flush engine through heater feed port on thermostat housing with tap water for 3 minutes (radiator drain should still be open and pressure cap installed).
10. Reconnect cooling system hoses and close radiator drain valve.
11. Position and reinstall the battery, connect the positive and negative cables. Check for the correct routing and connections of the heater hoses at the heater core and engine. (Figures 1 and 2)
12. Add one (1) bottle of Motorcraft(R) Premium Cooling System Flush to the degas bottle. (Do not use Motorcraft(R) Cooling System Cleaner F8AZ-19A503-AA which is for rust removal and will not remove the silicate gel residue).
13. Add tap water to the degas bottle until the water reaches the maximum of the cold fill range.
14. Install the degas bottle pressure cap.
WARNING
THE FLUSHING SOLUTION CONTAINS NO GLYCOL, THE SYSTEM WILL BOIL BEFORE THE FANS TURN ON IF THE PRESSURE CAP IS NOT FITTED CORRECTLY.
15. Idle the engine for an additional 5 minutes.
16. Run the engine for 10 minutes at 2500 RPM to clean the cooling system.
CAUTION
IF THE ENGINE OVERHEATS OR THE FLUID LEVEL DROPS BELOW THE MINIMUM FILL LINE, SHUT OFF THE ENGINE AND ADD FLUID TO THE DEGAS BOTTLE MAXIMUM FILL LINE ONCE THE ENGINE COOLS. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN DAMAGE TO THE ENGINE.
17. Drain coolant using Workshop Manual (WSM), Section 303-03.
18. Remove battery, using WSM, Section 414-01, to gain access to thermostat housing and remove both of the attached heater hoses.
19. Repeat Steps 7 through 11 to clean the flushing solution out of the cooling system.
WARNING
ALWAYS ALLOW THE ENGINE TO COOL BEFORE OPENING THE COOLING SYSTEM. DO NOT UNSCREW THE COOLANT PRESSURE RELIEF CAP WHEN THE ENGINE IS OPERATING OR THE COOLING SYSTEM IS HOT. THE COOLING SYSTEM IS UNDER PRESSURE; STEAM AND HOT LIQUID CAN COME OUT FORCEFULLY WHEN THE CAP IS LOOSENED SLIGHTLY. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY.
20. Refill and add 5.5 quarts (5.2 L) of coolant concentrate, Motorcraft(R) Premium Gold Engine Coolant with Bittering Agent to the cooling system. Measure coolant concentration and adjust to achieve a 50/50 mix. Set the fill level at the maximum of the cold fill range.
21. Install the degas bottle pressure cap.
22. Bleed air from the cooling system using the following procedure and top-off with 50/50 coolant mix if required.
a. Idle engine until the fan turns on, indicating the thermostat is fully open.
b. Increase engine speed to 2500 RPM for 30 seconds.
c. Idle engine for 2 minutes.
d. Repeat steps (b) and (c) five (5) times.
23. Verify satisfactory heater performance at idle using the Heater Performance Evaluation procedure. If heater performance is met, return the vehicle to the customer and do not continue with this procedure. If heater performance is not satisfactory then proceed to Heater Core Replacement.
Heater Performance Evaluation
1. Idle the engine at an ambient of 60 °F (15 °C) or higher until the engine is fully warmed up.
2. Set the climate control head to 90 °F (32 °C).
3. Set the mode to panel/vent and ensure A/C is switched-off.
4. Set the blower to highest speed.
5. Idle the engine for 5 minutes with the hood down.
6. The left-center vent discharge air temperature should be a minimum of 150 °F (65 °C).
7. If heater performance is met, run the vehicle for 10 minutes at 2500 RPM (to stabilize the coolant silicate concentration in the cooling system) before returning vehicle to the customer, and do not continue with this TSB. If heater performance is not satisfactory then proceed to Heater Core Replacement.
Heater Core Replacement
1. Replace the heater core, refer to WSM, Section 412-01.
2. Refill cooling system with 50/50 mix of coolant. Set the fill level at the maximum of the cold fill range.
3. Bleed air from the cooling system, following Step 22, under Cooling System Flush and top-off with 50/50 mix of coolant.
4. Run the vehicle for 10 minutes at 2500 RPM (to stabilize the coolant silicate concentration in the cooling system) before returning vehicle to the customer.
Parts Block
WARRANTY STATUS: Eligible Under Provisions Of New Vehicle Limited Warranty Coverage IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.
OPERATION DESCRIPTION TIME
082203A 2008 MKZ: Flush Cooling 2.4 Hrs.
System, Includes Time To
Perform Heater
Performance Tests (Do
Not Use With 8575B1,
18476A, 9600A, 10654C1,
04320A, 7210A, 7326C,
19700A)
082203B 2008 MKZ: Replace Water 2.9 Hrs.
Pump Inlet Tube, Flush
Cooling System, Includes
Time To Perform Heater
Performance Tests (Do
Not Use With 8575B1,
18476A, 9600A, 10654C1,
04320A, 7210A, 7326C,
19700A)
082203C 2008 MKZ: Flush Cooling 6.4 Hrs
System, Includes Time To
Perform Heater
Performance Tests,
Replace Heater Core (Do
Not Use With 8575B1,
18476A, 9600A, 10654C1,
04320A, 7210A, 7326C,
19700A)
082203D 2008 MKZ: Replace Water 6.8 Hrs.
Pump Inlet Tube, Flush
Cooling System, Includes
Time To Perform Heater
Performance Tests,
Replace Heater Core (Do
Not Use With 8575B1,
18476A, 9600A, 10654C1,
04320A, 7210A, 7326C,
19700A)
DEALER CODING
CONDITION
BASIC PART NO. CODE
8A080 53
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