How to winterize my sailboat (Volvo Penta MD7A), keeping it in Lake Geneva!

[DougR]

It may be that the raw water in the engine won't freeze because the general weather in your area isn't severe enough, but it's good to winterize the engine just in case of a cold snap and also to keep corrosion to a minimum.

Here is what I recommend you do:
- because you have a sail drive, you should close the water inlet valve at the sail drive....where the cooling water comes out of the saildrive
- next remove the coverplate from the sea water pump and remove the pump impellor so that it doesn't take a set over the winter. Set the impellor aside in a plastic bag
- replace the pump cover and tighten the screws with the gasket in place
- go to the front of the engine and open the engine block drain petcock on the lower starboard front of the engine. This is the petcock which can be seen in your photo....just ahead of the injection pump and right behind the flywheel
-now loosen and disconnect the water hose which is connected to the top of the thermostat housing..this is the hose which can be seen in your photo at the top front of the exhaust manifold
- now that the petcock is open and you have also opened the cooling system at its top you should have the cooling water which was in the engine draining out and into the bilge....let it all drain out. If nothing comes out, unscrew the petcock all the way from its fitting and stick a piece of wire in the hole and poke around, cleaning out the old rust, etc. until it drains
-using a piece of hose a few feet long which you connect to the elbow on the top of the thermostat housing, start to pour antifreeze into the engine thru the thermostat housing. This will fill the hoses back to the saildrive and then fill the exhaust manifold, the cylinder head and the block. Leave the block petcock open until you see some antifreeze coming out, then close it firmly. ( not too tight)
-when the engine is full, replace the hose on the top of the thermostat housing and tighten the clamp

Now the engine system is full of antifreeze from the saildrive to the exhaust system. If you want to get antifreeze in the exhaust system as well, just pour some down the hose on the top of the exhaust manifold going away from the thermostat housing.

As some have posted here, they like to suck antifreeze from a bucket or T fitting into the engine, but that is very dicey on a salt water cooled engine. If the engine is not fully warmed up to thermostat opening temperature, 90% of the antifreeze which you pump will just bypass the engine and go out the exhaust. Also, it's never a good idea to allow a sea water pump impellor to winter over in ethylene glycol, as it softens the impellor.

Come the spring time, don't forget to reinstall the impellor if it's in good shape, and open the valve at the sail drive.

DougR