Winterizing
- Thread starter obdoor
- Start date
Don't believe anything people tell you... including me!
I change mine at the end of the season when I change my oil and the engine is run several times before the boat is hauled. The following year when I change it, it looks brand new.
I change mine at the end of the season when I change my oil and the engine is run several times before the boat is hauled. The following year when I change it, it looks brand new.
The primary cause of death of raw water impellers--and the reason for the advise--is pink polypropylene glycol. The impeller is neoprene (check the brand) and neoprene is not comparable with PG (Google neoprene chemical compatibility--many sources). It gets hard and the vanes break off. The solution is to use automotive AF (ethylene glycol), which is compatible with neoprene (one of the reasons it is preferred in cars is better plastics and rubber compatibility).
Why do we use PG around boats?
a. Lower toxicity in potable water systems. It is the only safe choice (some use alcohol, but that has its own problems and is false economy).
b. The mistaken idea that PG is better for the environment. In fact, there is no difference. Just as zinc is lethal to fish but not humans, EG is lethal to humans but effectively harmless (EPA's own words) to marine life.
c. Biodegradability is equal. If they say different, ask for data. The EPA says they are equal in biodegradability.
So use auto AF on the engine (black water system too) and the impeller will last longer. I've done side-by-side testing for a research project. I generally get ~ 5 years and ~500 hours before I change them, and them it is only caution. Failure is closer to 1000 hours.
Why do we use PG around boats?
a. Lower toxicity in potable water systems. It is the only safe choice (some use alcohol, but that has its own problems and is false economy).
b. The mistaken idea that PG is better for the environment. In fact, there is no difference. Just as zinc is lethal to fish but not humans, EG is lethal to humans but effectively harmless (EPA's own words) to marine life.
c. Biodegradability is equal. If they say different, ask for data. The EPA says they are equal in biodegradability.
So use auto AF on the engine (black water system too) and the impeller will last longer. I've done side-by-side testing for a research project. I generally get ~ 5 years and ~500 hours before I change them, and them it is only caution. Failure is closer to 1000 hours.
I have to agree that I check the raw water cooling impeller every other year and the current one is five years old. It shows no sign of aging after approx. 500 hrs. I now believe I changed the previous impeller far too early. We don't get much below 0 deg. C in the winter and I don't bother with AF in the raw water circuit.
The raw water impeller isn't all that difficult to change, but I know of some that haven't been changed in several years of annual haulout and winter storage using the pink RV antifreeze. These are fresh water boats that may not even see six months in the water annually. It makes me wonder if salt water is more of a contributer to the hardening of the impeller vanes than the antifreeze itself...
I change my impeller every other year, and its difficult to discern which is the old impeller and which is the new one. As a result, there are always a couple of used "spares" in the parts bin.
I change my impeller every other year, and its difficult to discern which is the old impeller and which is the new one. As a result, there are always a couple of used "spares" in the parts bin.
On the Chesapeake I tend to use the engine less than a 100 hrs per season, I change my impeller every other year. But during winter lay-up, I hand-turn the engine just a tad about once a month when I visit the boat to check up things. I do this to avoid having the impeller vanes take a "set" from being in one position all winter. Works for me.
After I winterize the engine (no-alcohol PG) I pull the raw water impeller out of the raw water pump for the winter. The job is greatly improved with a SpeedSeal Life pump cover and this impeller puller. I haul my boat, so when she is on the hard, I open all the through-hulls for the winter. New impeller every two seasons. No visible wear or fatigue, ~100 - 150 hrs per season.
