Code P0128 - replaced thermostat

[smfabac]

On 1/24/2026 at 11:18 AM, John/Horace said:

Was that the factory original HOAT coolant in the engine still ? Early 2013 vehicles had hoat which is not compatible with oat, the coolant still used today.

Hoat is purplish when new, oat is closer to an orange color; kinda tricky for reliable assessment.

 

Dexcool does make oat coolant, compatible with other orange oat extended life coolants. But mixing hoat and oat coolant can make jell over time that will probably plug up your dash heater core etc.

 

To avoid any problems I would dump out all coolant and flush system with distilled water if possible. Then refill with a oat (organic acid technology) long life fluid; which will last vehicle life time. Google what I saying, this potential problem is out there. Heater core is not easy to change, even rad can have issues.

 

I'm in my mid 60s, working on cars is not as easy as it was years ago. But information is more available. Cheers.

John, 

Thanks for the warning.  The Dexcool I have is Prestone GM specific OAT bought for my wife's 2000 Chevy Camaro when she was loosing coolant. After a installing a new water pump, thermostat and radiator cap she is good to go. The service on my 2013 Journey at 197,647 included plugs, fuel filter, PCV valve and coolant "exchange" using 68163848-AB and when I checked that part number I see:   OAT, 10 Year, Chrysler, Dodge, Jeep, Fiat, Ram.  It took a while googling to verify that the Prestone (upc797496860958) meets MS-12106 as specified in my owner's manual. 

 

Previous service was 114,750 when the oil filter adapter housing was replaced - new spark plugs, and coolant 68163848-AB.  The service ticket does not specify if the coolant was completely drained for the service or added as needed.