Gradual loss of coolant

[Breakin Away]

All of the coolant leaks from our boat have been the connections at the back of the hot water tank.  Very hard to get at!!!

Jack

Great clue! Thanks.

That's one path of leakage that I didn't trace. I'll have to check and see whether the potential leakage path leads to the center or aft section of the keel sump. (I found the coolant in the aft section.)

My hot water tank was replaced about 3 years ago by the prior owner, but that doesn't mean that the fittings are immune.

[tonywright]

Coolant may have been left in invisible parts of the bilge following the coolant change (it is hard on the M35 to do a coolant change without spilling a little into the bilge). Moving the boat 75 miles may have dislodged the coolant from its hiding places. Thinking this might just possibly be the source if, as you say, the coolant level in the reservoir did not change.

Tony

[Stu Jackson]

You over filled it.  Remember cars before the reservoir s?

[Breakin Away]

You over filled it.  Remember cars before the reservoir s?

That was my first suspicion, but I can't find any evidence of that. Where would it overflow from? How would it work its way to the keel sump?

Actually I don't remember cars before the reservoirs.

[Jack Hutteball]

When my HWT connections were leaking, the coolant was always in the aft section of the bilge.  The coolant would run down the underside of the sink cabinet floor and drip off the end right into that section of the bilge.  Look under the cabinet floor with a mirror or feel under from the bilge area and see if you feel any moisture there.

Jack

[Breakin Away]

I am not sure yet, but I may have found traces of EG residue coming from the engine area to the bilge (not the hot water tank). I've borrowed a radiator pressure tester to apply some pressure to the system, and placed towels and pads in various places hoping I'll see where the coolant is dripping from. Before I apply the pressure tomorrow, do any of you have tips on how to do a pressure check? (Can't find anything in the wiki on this.)

In particular, since my coolant reservoir is mounted higher than my motor, I want to stem to flow of coolant once I take off my pressure cap. Can I just put a pinching tool on that hose, or will that damage the hose?

[KWKloeber]

there's no mystery, just pump it up and wait to see if it holds.  If not start looking for leaks.  the cap is like 12-15 psi, so that's the max to test at.

Sure you can pinch it off w/ a vice grip, just enough pressure, no more than necessary  (they make a kinda rounded pinching pliers for that purpose.)  Put a rag on it so you don't have sharp edges to cut the hose.  Or pop the hose off and block the end w/ a bolt or pc of gorilla tape.

kk

I am not sure yet, but I may have found traces of EG residue coming from the engine area to the bilge (not the hot water tank). I've borrowed a radiator pressure tester to apply some pressure to the system, and placed towels and pads in various places hoping I'll see where the coolant is dripping from. Before I apply the pressure tomorrow, do any of you have tips on how to do a pressure check? (Can't find anything in the wiki on this.)

In particular, since my coolant reservoir is mounted higher than my motor, I want to stem to flow of coolant once I take off my pressure cap. Can I just put a pinching tool on that hose, or will that damage the hose?

[Ron Hill]

Breaking : A couple of answers to your questions:
1. You need a Zn anode - because from Rock Hall if you go north to the C&D or south toward Annapolis (or further down the Bay) you are getting into salter waters!!
2. To trouble shoot and find a leak the best way is to put out a fuel diaper (West Marine) and cut it so it goes under the engine.  Also put a diaper under the HX.  Then you can look for the tell tail drips on the white diaper.

The diaper will also show up fuel and oil leaks.  I keep one under the engine at all times.

A few thoughts