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2012 Chrysler 300 - thermostat replacement (advice)

Discussion in 'Repairs, Maintenance, Help' started by Hemidakota, Nov 20, 2017.

  1. Hemidakota

    Hemidakota Active Member

    Jan 24, 2017
    I have to say, follow the manual or the advice of the mechanics when it comes to replace the coolant or all fluids before 120,000 mile mark.

    I did not replace the coolant until 140k miles when a engine light came on when the wife was driving the 300. It was the thermostat code. I failed to recall the exact code but never-or-less, I needed to stop procrastinate on replacing the coolant. I will inspect the parts when taken off to see if it had specific signs of problems.

    I have already ordered a new coolant bottle and the orange embittered MOPAR coolant (2 gals.), along with a new MOPAR thermostat/housing. The housing is plastic (Poly material). This is reasoning of replacing it as a whole vice just the thermostat. Law of physics here with heating and cooling.

    I do recommend in never go outside of what works when it comes to parts unless you know who is the supplier of that part.

    It took me only 20-minutes to replace but the thermostat/housing and the coolant overflow bottle. Then reset the OBD. Amazing how much Google and YouTube has helped owners in doing it yourself fixes.
  2. ImperialCrown

    Level III Supporter

    Jun 8, 2008
    Be aware of a TSB # 21-007-12 that can correct a possible erroneous P0128 - thermostat rationality fault on early 2012's. PCM software updates should be covered under the 8/80 extended federal emissions warranty. The main purpose of the TSB is 8-speed shift enhancements, but the 'ck eng' may light with the fault codes shown below:

    NUMBER: 21-007-12
    GROUP: Transmission and
    Transfer Case
    DATE: March 08, 2012

    Flash: Launch Shudder And/Or MIL Illumination And/Or Harsh Shifts With Transmission
    Operation Improvements
    This bulletin involves flash reprogramming the Transmission Control Module (TCM) and
    the Powertrain Control Module (PCM) with new software.
    NOTE: Both modules must be updated for all changes to be implemented. Refer to
    the “Symptoms/Conditions” for a detailed description of the changes.
    2012 (LD) Charger
    2012 (LX) 300
    NOTE: This Service Bulletin applies to vehicles built with 3.6L engine (sales code
    ERB) with a 8 speed automatic transmission (sales code DFG) built before
    January 17, 2012 (MDH 0117XX).
    Some customers may experience transmission shift, engagement, shudder or operation
    concerns. Refer to Transmission section below for details. Customers may also notice a
    MIL illumination. Upon further investigation by the Technician any of the following DTC's
    may be set:
    i. P0441 - Evap Purge System Performance.
    ii. P0420 - Catalyst Efficiency (Bank 1).
    iii. P0430 - Catalyst Efficiency (Bank2).
    iv. P0133 - O2 Sensor 1/1 Slow Response.
    v. P0153 - O2 Sensor 2/1 Slow Response.
    vi. P0300 - Multiple Cylinder Misfire.
    vii. P0301 - Cylinder 1 Misfire.
    viii.P0302 - Cylinder 2 Misfire.
    ix. P0303 - Cylinder 3 Misfire.
    x. P0304 - Cylinder 4 Misfire.
    xi. P0305 - Cylinder 5 Misfire.
    xii. P0306 - Cylinder 6 Misfire.
    xiii.P113D - O2 Sensor 1/1 Slow Response (High Frequency).
    xiv.P113E - O2 Sensor 2/1 Slow Response (High Frequency).
    xv. P0128 - Thermostat Rationality.

    i. Paddle shifting stops working until ignition is cycled. This can happen with a lot of
    aggressive paddle shifting in low gears. The transmission calculates the clutches are
    getting hot and will disables paddle shifting until key off event. The software has
    been changed to bring back the paddle shifting function as soon as clutch
    temperatures are reduced. The cluster will also provide a message to the driver that
    informs them the paddle function is disabled.
    ii. Vehicle will not stay in Sport mode. This happens whenever the vehicle is shifted out
    of drive. The updated software keeps the vehicle in sport mode until the driver
    deselects the sport mode or the ignition is cycled.
    iii. Launch shudder. This condition happens when the vehicle is started and
    immediately shifted in drive and 15% or more throttle is applied.
    iv. 1 - 2 or 2 - 3 upshift bump in cold temperatures between -22° F (-30° C) and 50° F
    (10° C).
    v. 2 - 3 upshift bump. This condition occurs when the driver lifts their foot off the
    accelerator pedal right before the transmission perform the 2 - 3 upshift.
    vi. 3 - 2 downshift bump. This condition happens during light braking or coasting down
    with no throttle input.
    vii. 7 - 6 downshift bump. This condition happens during light braking or coasting down
    with no throttle input

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