Coolant leak

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drb1025

Guru
Joined
Oct 20, 2012
Messages
703
Location
USA
Vessel Name
Fiddler
Vessel Make
DeFever 46
I have a small coolant leak where the coolant line from the hot water heater connects to the engine. At the engine connection there is a shut off ball valve. The leak is between the ball valve and the engine. I have not worked on this before and am wondering what the process is for fixing the fitting leak. Do i need to drain the coolant? Or can i shut off the ball valve, disconnect it, and reseal the fitting without draining the coolant? Thanks for your help!
 
If you are lucky, it may be possible to just close and tighten up the ball valve, (after loosening off the hose clamp so the hose isn't twisted), but the proper way would be to:

1. Drain the coolant to below the level of the valve.
2. Loosen and disconnect the hose.
3. Unscrew the ball valve and hose tail fitting
4. Clean up threads with a wire brush and inspect for corrosion
5. Apply good quality sealant suitable for the job to the male threaded fittings.
6. Reassemble valve and fittings
 
Another idea, if I understand the post correctly and the leak is where the valve screws into the block- would be to use something like a pair of needle nose vice grips clamped down on the hose a foot or so from the valve. This stops flow from that side. And with the radiator cap still in place on a COLD engine, you would unscrew and remove the ball valve. The block will barely leak- you could even plug it with one of those wooden taper plugs we all have down in our "engine compartment" and then clean the threads with a hand wire brush, apply liquid Teflon, and reinstall. Put the hose back on and replace any lost coolant.


1983 Present 42 Sundeck
Twin Lehman 135's
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Thanks for the instructions! Either way doesn't sound very complicated. It's a slow drip so not an emergency but something that goes on the list of items to take care of before spring.
 
I vote for clamping the inlet hose because you may have to unscrew the ball valve. Yes, cold engine is a must.
 
And you might find that if you can elevate the open end of the hose enough to get it higher than the radiator cap, you can stop any siphoning from occurring.

Be careful clamping the hose with anything sharp like vice grip teeth. A couple small pieces of scrap wood in the jaws of the clamp might work well....and spread the force over a larger area to prevent deterioration of the hose.
 
indeed after removing the hose it would only take a few seconds to plug the hose with a rag or wood plug. There will also be coolant leaking from the heater but again it can be plugged easily and adding a quart of coolant is no big deal
 
If you use a wood plug don't put the project aside for any length of time; you may very well have a problem getting the wood plug back out. Personal experience.
 
Usually a plumbing project at home takes three trips to Home Depot to finish. I was able to fix the coolant leak with only two trips to West Marine. One for the right sized tube to attach to the petcock drain and the second for a small hand pump to return the coolant to the engine. No room to pour it back in. No more leak!
 
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