SEE VIDEO BELOW
When there is a small coolant system leak it can prevent the cooling system from reaching operating temperature. This can cause code P0128 for coolant temperature below thermostat regulating temperature.
The engine may have a small leak and might need the occasional coolant top off. The first diagnostic step is to find and fix the leak. But, before the vehicle is returned to the customer, clear the code and make sure it does not return during a test drive. This video is sponsored by Bar’s Leaks.
