Refiling closed cooling 340 monsoon help!!!

[Ducatifan]

Hey crew, I’ve recently done some maintence on my closed cooling system on my 340 monsoon,removed the tank and had it cleaned and pressure tested ,replaced the hoses and clamps and a general clean out overall.

Ive been told that the system needs to be bleed when refiling from the bottom to the top to prevent getting an airlock with the system or within the engine block.

Can anybody shed some light on this subject or direct me as to where I could the information as I can’t find anything about it in the manual or related videos.I would really like to no that I’m doing it right so I don’t create any further problems Thankyou.Matt.

[JeffK]

They typically bleed themselves pretty well on their own.  Your only real issue is getting coolant below the thermostat to start, which can be done by pulling the two hoses going from the thermostat to the lower part of the block and adding antifreeze directly into them.   Depending on where your reservoir sits, adjust the jack stand in the front to make the reservoir sit at the highest point.  Fill, let it sit a bit for the air to travel to the top, then fill again.  If you want to take a picture of your setup, including the reservoir and thermostat housing, I can highlight the correct hoses.  You just really need to make sure you have coolant on the lower side of the thermostat before you start your boat so you don't cook the hoses.

[csleaver]

The last 340 Monsoon I've seen with a full closed cooling system had bleed fitting on each exhaust riser.  The heat exchanger and pressure cap are not the highest part of the system and there is no degass reservoir.  It is very difficult to purge all of the air from the cooling system and I would recommend using a vacuum cooling system filler.  

These work well, but there are other brands out there.

https://www.jbtools.com/uview-550000-airlift-cooling-system-tester/