Does anyone know the part number for the thermostat housing gasket? I have a small but steady leak at the housing. I have included photos. Hard to tell what it is but the photos are directly behind the alternator mount. I have a heavy amount of rust in the system so I will be doing a flush along with a block heater and a coolant filter install. It may be covered in other threads but I do not have oil in my cooling system. Should I just dump the coolant, and run 3 bottles of Thermocure in the system then flush again and re-fill with heavy-duty coolant specifically for HD diesel engines that have all of the additives in it? Does anyone have any photos of where they mounted the coolant filter and where did they tie into the engine block for proper flow? I have seen a few other photos on putting the filter on the firewall to the right of the cab heater but that puts it directly above the exhaust pipe and I did not want all of the heat directly below the new filter. Thanks guys!