Turbochargers operate at high temperatures. The Cool Down Timer is designed to keep the engine running when the ignition is turned off to prevent turbocharger bearing failure that could occur when the engine is shut down, stopping the cool lubricating oil flowing to the turbocharger while it is still hot. If the oil flow is shut off too early, the remaining oil in the bearing housing will overheat causing coking of the bearings which causes both premature bearing wear and reduced oiling of the bearings. Allowing the engine to idle to a minimum operating speed gives the turbocharger time to cool down. The CDT is adjustable for up to 5 minutes of idle time, or optionally works with any K - Type EGT probe for temperature - based shutdown.