Water drains -- where are they?

[Rich]

In your winterizing article, you suggest, in step number 2 that one:"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." Where are the drains on the engin block and manifold located? I have a 30gm30f and the manual doesn't have a picture that calls out the drains. I'm a new boat owner and trying to overcome my un-mechanical background handicap. Thanks for your help.

 

[Paul Akers]

I did mine

I have a 3HM35F and just changed my antifreeze. There are 3 petcocks on my engine (1 on port, 2 on stbd). The stbd ones are located on the underside of the heat exchanger and have a clear plastic tube attached to them. The forward one has a gnarled, 3/4" round knob that twists open several turns (counterclockwise). The aft is a "T" similar to an auto radiator petcock (1/2 turn to open the drain).The port one is half way back on the block. It too, has a gnarled, 3/4" round knob that twists open several turns (counterclockwise) to open the drain. BE SURE THE PRESSURE CAP IS OPEN or else it won't vent the system to drain.To drain the water heater, I disconnected one of the hoses and put a wet vac (suction side) on the water heater hose and drew out the antifreeze that way. (Works super).When the engine was draining, I let it run into a pan and vacuumed the pan before it overflowed.When replacing the antifreeze make sure everything is reconnected and that the petcocks are closed. I used 7 quarts of 50/50 antifreeze mix. Fill it up as much as you can. The thermostat will be closed, so iwon't fill completely. Run the engine for aprox 10 minutes at idle and feel the water heater hoses to warm up. This will tell you that the thermostat is open and passing the new antifreeze. Let the engine cool and then check the antifreeze again and fill it up. Repeat the fill process as necessary. I only had to do it once. Lengthy, but it works for me.Good luck

 

[Gordon Torresen]

Winterizing

If your engine has an F in it, you are reading the wrong instructions. The block and manifold must be drained only on sea (raw) water cooled engines.