Draining raw water cooling manifolds

[MRWood]

When you drain the raw water cooling manifolds for winterizing do you guys leave the drain plugs out after draining the water. I was thinking it might be better keep them out to let it dry out inside. Does it really matter?

 

[bigbruce]

Don't think it matters - but if you do leave them out, make sure you make a note to yourself to put them back in before you start up in the spring!

 

[SpringVelocity]

I have to do this as well except will be using all winter...

 

[rockdog]

I installed little ball valves, instead of the plugs. Now, when I want the drain the manifold and the heat exchanger, I just open the valves and let the water drain out. I also use my boat during the winter, so this is the easiest way...

 

[MRWood]

Thanks for the input guys. I like the ball valve idea.

 

[SpringVelocity]

I installed little ball valves, instead of the plugs. Now, when I want the drain the manifold and the heat exchanger, I just open the valves and let the water drain out. I also use my boat during the winter, so this is the easiest way...

Hey I have a mercruiser 3.0L can you post a pic or a link of what you did.. I will be using my boat all winter as well... I am new to the inboard winterizing thing...

 

[bigbruce]

Don't forget to drain the raw water pump as well.

 

[Wondermur]

Hey I have a mercruiser 3.0L can you post a pic or a link of what you did.. I will be using my boat all winter as well... I am new to the inboard winterizing thing...

With the 3.0 Mercruiser you need to be careful that all the water has drained out of the manifold and block. Sometimes rust and crud blocks the hole at the manifold especially and water is left in there. Best to poke some wire in a couple of times to be sure the hole is clear and all the water has drained out.
Also if fogging a cold engine make sure you warm it enough for the thermostat to open so that no water is left in there when you drain the manifold and block.
Cheers.

 

[SpringVelocity]

Thanks I am using at least once a week so won't be fogging. As far as I can tell all I need to do is drain block and the fresh water jacket, and that's it. I am wondering if necessary to even have any heat in enclosure... Anyone have some easy alternatives to that...I have a small oil heater not doing anything.... Was wondering if that would do OK.. Or maybe don't even need it?

Boat is covered in shelter away from rain but its not a heated garage.

 

[rockdog]

Yes, you should always have something on hand to put up the hole. It's not specific to 3.0l, but rust and sediment does collect in the bottom of the manifold(s). So I open the valve, then keep poking up the hole, just as you would when removing the plug to drain.

Spring- the drain plugs on mine were 1/8 NPT threads. So I just matched that up with a 1/8 NPT nipple, and a ball valve. I did the same for the raw water side of the heat exchanger. Very simple to do, I'll send you a pic of the set-up.

 

[SpringVelocity]

Thanks man awesome..

 

[rockdog]

Here is what I used on mine.....'1994 merc 3.0l with a heat exchanger



Unscrew your plugs (manifold and Raw water Side of exchanger), and just make sure yours are also 1/8" NPT threads.

 

[SpringVelocity]

Thanks tahts awesome..... I am going to switch to that ...Hey do you heat your compartment since you fish all winter? I am hesitant to put a light bulb in there.

 

[rockdog]

I do not heat my engine compartment over the winter. I would have some concerns with fuel being present in the lines, carb and such.

Im not saying you should or should'nt heat yours, but just that I dont heat mine.

 

[rockdog]

Also, make sure you remember to 'close' the valves. Or you will slowly fill up the bilge with water next time you go out.