Whale 6 Ga. water heater

[bgallinger]

I have a Whale water heater that has operated perfectly until now. It heats water from the circulating coolant from the engine (typical). It has always given me scalding hot water, but now, the water is just warm.
Any ideas anyone?

[sailormed]

Engine thermostat?

[Oldwheels]

Flush the thing. I recently took one out of my boat and was surprised at how much crud was in it. This will also extend its life.
And do check engine thermostat or look at engine temp and coolant levels.

[bgallinger]

Thanks for the suggestions! I will replace the thermostat if I can find one.

[Cheechako]

Dont replace the thermostat unless you take an engine temp reading. Waste of time. Think about it.. a thermostat opens when the engine heats up. When the engine is hot it is fully open. Pretty hard for a Thermostat to fail and make the engine too cool. Too hot... yes. The engine could take longer to get fully hot, but eventually will.

Do easy stuff first:
Look for crud at any joints in the lines from the engine to the water heater. Maybe disconnect the hose from the engine to the heater and see how the flow is with engine running. Or if gunk comes out.
Also, some hoses fail with the liner coming apart. A piece can then block the hose. Especially at the hose connections to the heater. Something must be partially blocking water flow to the heater.

[motion30]

Originally Posted by Cheechako

Dont replace the thermostat unless you take an engine temp reading. Waste of time. Think about it.. a thermostat opens when the engine heats up. When the engine is hot it is fully open. Pretty hard for a Thermostat to fail and make the engine too cool. Too hot... yes. The engine could take longer to get fully hot, but eventually will.

Do easy stuff first:
Look for crud at any joints in the lines from the engine to the water heater. Maybe disconnect the hose from the engine to the heater and see how the flow is with engine running. Or if gunk comes out.
Also, some hoses fail with the liner coming apart. A piece can then block the hose. Especially at the hose connections to the heater. Something must be partially blocking water flow to the heater.

I disagree I have seen many thermostats fail in the open position. The one on my generator is stuck open right now. Very common

[Cheechako]

Originally Posted by motion30

I disagree I have seen many thermostats fail in the open position. The one on my generator is stuck open right now. Very common

I agree with you! What I'm saying is the engine will heat up to normal temp with it stuck open, but just take longer. It's just like it is after a half hour of running! Unless you are just slow idling at low rpm and no load.

[JimsCAL]

Did you change your anti-freeze recently? Air in the hose loop?

[sailingchiro]

My hose to the water heater had separated (inner core) and clogged the line. Take your hose off and see if you can blow through it. Now it is scalding hot again (160F).

[bgallinger]

Thanks to all who responded! I changed out the thermostat first as I had a spare, then ran the engine at idle for an hour. I saw no change in water temp., so I pulled off the coolant hose ends to check flow through the hoses and water heater, then re-filled the hoses with anti-freeze. Ta Da!! Hot water+happy wife!