Return to the Torresen Marine Home Page

Winterizing Engines

Winterizing Sea Water Cooled Inboard Engines

This is to give general guidelines for the winterization of inboard engines that do not have internal heat exchanger type cooling systems. Variations will become evident in different brands of engines, however the principals will be the same. Engines do not freeze. It is the water within the engine and peripheral equipment that freezes and causes damage. To preclude freeze damage you must either eliminate the water or make it so that the water will not freeze.Good steps to follow:

  1. Shut off the cooling water seacock if the boat is still in the water.
  2. Open the drains on the engine block and manifold – make sure that water comes out. There is sometimes blockage at the plughole of petcock. If a water heater is involved, it too must be drained.
  3. When the water has drained, close the drains.
  4. Remove the hose from the seacock and put it in a jug of environmentally friendly antifreeze. If easier, replace the hose with another connection to the inlet side of the seawater pump.
  5. Start the engine and run it until antifreeze comes out the exhaust. Most antifreeze will by pass the engine, which doesn’t matter because it has been drained. A little will go into the engine that will take care of any water that ran down from the walls inside the engine.
  6. When, or if, the boat is out of the water, open the seacock to drain water from it. If the boat is to stay in the water, the seacock must be treated to prevent freezing.

Running the engine to temperature to open the thermostat and then introducing antifreeze requires that the antifreeze be at the same temperature so that the thermostat does not close when contacted by something cool. It is highly recommended that if the lube oil needs to be changed that it be done prior to lay-up so that fresh oil is coating the innards of the engine. If fuel filters are in the plan do them first. Then start the engine to check the fuel filters and warm the engine to facilitate the oil change.

Winterizing Your Fresh (Internal) Water Cooled Inboard Engine

This is to give general guidelines for the winterization of inboard engines that have internal, heat exchanger type cooling systems. Variations will become evident for different model engines, however the principals will be the same. Engines do not freeze. It is the water within the engine and peripherals that can freeze and cause damage. To preclude freeze damage you must either eliminate the water or make it so that it will not freeze.Good steps to follow:

  1. Check the specific gravity of the internal coolant. Antifreeze checkers are widely available, and very cheap. Depending on your location be sure that the freeze protection is adequate. If protection is marginal, either drain some off and add 100% new or change the whole lot. Antifreeze should be changed every three to five years, according to Yanmar and the AF makers.
  2. Shut off the seawater intake seacock, if the boat is in the water.
  3. Take the hose off the seacock and put it into a jug of environmentally friendly antifreeze. It is sometimes easier to remove the hose at the pump and use a different hose into the jug.
  4. Start the engine and run it until the antifreeze comes out the exhaust.
  5. Reinstall the hose to the seacock.
  6. Reopen the seacock after the boat is hauled. If the boat is to be left in the water, the seacock may require winterizing, again depending on the severity of your winter.

If you are not located where winterizing is required, read this through and purr. It is highly recommended that if the lube oil needs to be changed that it be done prior to lay-up so that fresh oil is coating the innards of the engine. If fuel filters are in the plan do them first. Then start the engine to check the fuel filters and warm the engine to facilitate the oil change.

Share or bookmark this story:
[Digg] [Reddit] [del.icio.us] [Facebook] [Technorati] [Google] [StumbleUpon]

This entry was posted on Monday, October 22nd, 2007 at 12:49 pm and is filed under News From Torresen Marine, Winterization. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Leave a Reply