Tractionless

I've noticed zero water pressure difference between a new Merc impeller in a Harden housing vs. 2 years later. I therefore replace mine at 2 years.

AllDodge

iTrader: (1)

While I only have one year with a pressure gauge, I have not seen any temp changes doing it every 2 years. When the impeller is removed they all look about the same.

Have not forgot about measuring the pressure at the thermostat housing to compare with the block pressure. Hope to get around to installing a second gauge this season.

Do think I'm going to go back to the composite housing next season, that thing is just heavy.

ThisIsLivin

I converted to the stainless housing as well. The stock plastic housing and impeller would be toast after 1 season. With the Hardin, I pull the impeller when I winterize and by spring it looks pretty good. I have oil and water temp gauges but no water pressure. My temps are identical from year to year so I feel very comfortable getting 2 seasons out of an impellor. I also took a die grinder and ported my pump housing to remove rough edges and improve water flow. I run a crossover system with a 150 thermostat and I barely hit 150 unless I'm doing over 60. Water output out of the headers is significant even at idle. I like to hit it hard just before I get into the no wake zone to go down the river and then drop to an idle. My water and oil temps don't spike and temps drop right down quickly and I'm running an undersized cooler. I absolutely wouldn't go back to the plastic housing.