The pump, not the engine. Gerry, you and I don't need it but in cold country I heard it is common. I guess there isn't a good way to completely drain a pump so anti freeze is added. Unless pump anti freeze prevents hard water scale build up then maybe using it after every use would be helpful. Those unloader valves on the pump plumbing are what goes first and almost always due to hard water build up. 

Bob
Last Edited By: NevadaWalrus Aug 29 11 1:15 PM. Edited 1 times.