M3-20 Cooling System Maintenance

[Mike Elmore]

I just bought Windward Hull last year. It's my first boat. I've been learning things as I go. The manual I have has incorrect directions for draining the fresh water coolant. Engine maintenance is one of the things I have (up until now) left to the yard and it runs fine.Now that I've had the problem with the cracked water lift chimney, I had to get the coolant out of the exaust manifold so I could unbolt the header pipe to get the pipe/hose off the water lift. I'm embarassed to say I had to syphon it out the coolant fill cap.The manual says that there is a drain petcock for the coolant on the block below the alternator. There's surely nothing there. The diagram (and motor) has a drain plug on the starboard side of the motor close to the oil dipstick. Is this the freshwater coolant drain?On refilling, just refil until it's full up to the cap and then check for air pockets? Also...I have a coolant resovour in the port lazarette. It has a hose attached to the bottom of it that runs to just under the coolant cap so it can drain into the exaust manifold as needed I assume. There is a clear 1/4" hose attached to the top that just runs down into the engine box and attaches to nothing. Is this clear hose a breather hose so the plastic resovour doesn't collapse? ...or should it be attached to something to make it a closed system?Any help is appreciated. I've got a handle on enough things that it's time to not have to pay anyone for engine maintenance anymore.Mike ElmoreWindward HullC28 - Hull #7

 

[Terry Jack]

Cooling system

I have hull 353, an earily 94, one of the last original models.I will try to remember how to do it with my boat 3 hours away.There is a drain plug on the heat exchanger. The part with the radiator cap. Open it and the pet cock at the overflow reseviour in the lazarette and it should drain. I can remember off hand where the block plug is. I would try cracking the one youmention and see if it is antifreeze. There is nothing much youcan hurt. After you refill you must bleed the system. The pet cock in the lazarette and the one on the heat exchanger reseviour are for that purpose. If you do not bleed the system you might get an airlock and overheat. I believe that the 2 clear hoses you are refering to in the lazarette are: 1. recirculation line between the exchanger and the overflow tank2. breather so the tank does not collapse.I wish I could be more specific but it has been a year since I have done mine. good luck and let's hope someone who can go look at their boat offers some more specific help for you