Eliminate the Chevy Rub
Certain 2015-2016 Chevy Express vehicles equipped with a rear HVAC system may have contact between the rear leaf spring shackle bolt and the rear HVAC coolant lines that may rub through. The rubbing creates a coolant leak that can cause the engine to overheat, as well as a loss of HVAC performance.
Replace the shackle bolt with P/N 11588857. If required, replace the auxiliary air conditioning evaporator hoses 23172815 and 23172814, auxiliary heater inlet and outlet hose 20970677 and 20970676 (again, only if needed).
Remove and discard the original bolt. Install the new bolt and tighten first at 74 ft-lb, followed by an additional bolt rotation of 210 degrees.