News Technical Service Bulletins

Infiniti A/C Issue Fix

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Cut the original thermostat as shown here for V8 applications.

| Photo Credit: Infiniti

This bulletin applies to 2014-2015 Infiniti Q70/Q70 Hybrid, 2011-2013 M and 2012-2013 M Hybrid vehicles equipped with V6 or V8 engines.

Confirm that with the engine running at full temperature and the HVAC set to vent (face),and 90-degrees Fahrenheit on both sides, the vent temperature on the passenger side is more than 10 degrees Fahrenheit colder than the vent air temperature on the driver side. And then when the HVAC control is adjusted to 60 degrees Fahrenheit on both sides, there is a noticeable change from warm air to cool air discharged from vent on both sides, this confirms proper MIX door operation - and no HVAC DTCs are stored.

INFIN02.jpgInstall the upper seal-equipped section into the water inlet (V8).



1. Darin the engine coolant;

2. Modify the thermostat (required for flushing);

3. Flush the cooling system three times with Nissan Long Life coolant;

4. Replace the heater core;

5. Replace the thermostat with gasket

INFIN03.jpgFor V6 engines, cut the original thermostat as shown here.


After draining the coolant, remove the thermostat/water inlet. Cut/modify the thermostat at the locations shown in the accompanying photo. Install the modified thermostat. Reinstall the water inlet without the thermostat. Fill the cooling system with Nissan Long Life antifreeze/coolant.

Start the engine and maintain 3000 RPM for 30 seconds. This will suspend any debris in the cooling system, which will then be drained.

Immediately drain the cooling system. Repeat this, fill system, hold at 3000 RPM for 30 seconds and then drain two additional times for a total of three times.


On V6 engines, install the water inlet alone without the thermostat. Once the system has
been properly flushed install a new complete thermostat for both V6 and V8.


On V6 engines, install the water inlet alone without the thermostat. Once the system has been properly flushed three times, install a new, complete thermostat for both V6 and V8. Replace the heater core. Do not replace the A/C unit assembly.

Replace the modified thermostat with a new replacement thermostat, mount the inlet and fill the cooling system with Long Life antifreeze/coolant.

Bring the engine to normal operating temperature and then verify the repair.

PART                                    P/N

V8 thermostat............... 21200-AD21A

V6 thermostat............... 21200-31U03

V8 thermostat gasket..... 11062-1CA1A

V6 thermostat gasket...... 13050-31U00

Heater core..................... 27140-1MA0A

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