Coolant systems are essential to ensure the engine is operating at the proper temperatures. Without properly working coolant components, coolant systems can fail and cause damage to various engine components.
A driveline is basically the part of the vehicle that transfers power from the engine to the road. It usually consists of differentials, propeller shafts, constant velocity joints, side gears, and drive shafts.
If you own a heavy-duty vehicle, chances are that it uses an EGR system to reduce the number of Nitrogen Oxides (NOx) entering the atmosphere by recirculating exhaust gases back into the engine for combustion.