Engine Heating Hot water

[Stephen M]

Our 420 Passage has the engine coolant looped through the hot water heater.
We have a device that looks like a Tee/clean out.
We noticed that this device had a small, tiny leak (few drops) as we were opening up all hatches for final close up due to winter.
I would like to get comments on what is the purpose of this device.
Regards
Stephen

 

[stuartsw]

Look like a shut-off valve to me.

 

[Sailgunner]

Maybe a port to flush the system.

 

[Ralph Johnstone]

Wild guess says it's an air release fitting, if it's on the coolant side.

 

[RoyS]

Drain

 

[jssailem]

With all the on line plastic T fittings on the internet I thought it would be relatively easy to find a match.


This was the closest that popped up. It looks to me like you would unscrew the top fitting (cap) and attach a garden hose to the unit to flush out the coolant system or drain the cooling system.

That said, ;lift the hose till it is above the coolant tank reservoir on the engine, then carefully unscrew the cap. Might want a bucket and a few towels around to grab and capture the coolant as it drains.

 

[Don Lucas]

I have the same fitting on my 410. I always have assumed it was a flush connection.

 

[sailcapt340]

I have one of those on my 340. Mine is on the top of my engine though. It's a flush out fitting for the engine antifreeze. When I replaced my water lines throughout the boat a few years back I put that fitting back into the new hose, in the same spot.
It's to connect a garden hose to, so you can flush out the system. Personally, I've never used it. Mainly because what " jssailem " just said....you need a bucket and a lot of towels handy.
Yours is in a very low spot compared to mine, you should be able to get an aluminum tray under there to catch the coolant. With minimal cleanup involved.
US Plastics may have one or something similar you could use to replace it. Or eliminate it, if you don't think you'll ever get a hose in there to flush the system.
I just posted a photo of an Overfill Bottle for a PSS System I have someone asked about. And just by chance that same fitting got into the picture. Take a look.

 

[karellen]

I have two of these on my 356, one at the engine and one at the water heater. After replacing all my fresh water hoses I needed to use these twice. The first time was to attach a garden hose to flush the system. Then, after refilling, I needed to use both of these fitting to top off the water in the system. Just filling from the radiator left air in the system.