The shop is in the process of checking the strength of the anti-freeze in all trucks and if needed lowering the protection to -25 degrees in preparation for the winter months. If you have to add coolant or anti-freeze use 50/50 mix. If you have to add water, please inform the shop so the strength can be checked. It is also a good idea to check your wet tank daily for moisture, drain if needed. Excessive moisture can be an indicator that your air dryer may need serviced, if so, please inform the shop on your DVIR.