True or False: Over time, coolant/antifreeze becomes very acidic. (Once I noticed the thermostat that I was going to replace anyway, was broken and the spring was laying in a puddle of the green stuff at the bottom of the housing, I decided to look at the system a little further. Took off the lower thermostat housing and found that it was heavily/deeply pitted in the area where it attaches the the engine just below the valve cover. Took it in to NAPA, since I was going there anyway, and ask them if they have ever seen this. They told me that the fluid turns acidic over time and will do this is not changed frequently enough. If this is false, what would cause it to pit so heavily, almost all the way through the metal?) True or False: There are two types of coolant/antifreeze. One kind for modern engines that are not prone to rust on the inside, and another kind for engines that tend to accumulate rust on the innards. This latter type has some sort of fine grit in it to scour away rust deposits inside the cooling system. If this is true, what type of fluid do you long time cruisers use, and is it easily found at AutoZone or AdvancedAuto? Since my cruiser sat for a good number of years in a barn in St Louis until this past August and indeed, the coolant does turn acidic, and has eaten its way through the thermostat and its housing, should I consider replacing the water pump too? How do I tell if I need to replace the water pump? Thanks!