Columbine's heat exchanger has recently been replaced, just for general principles on our 15 year-old C-30 with a Universal 25XP engine. Our timing was good, because our old HE bracket had broken on our trip down the Sacramento River on a strong ebb against strong wind causing steep waves. If you buy a new 3" heat exchanger, you will need to buy a new bracket,$22, because the HE is slightly different. Chuck