engine alarm sound

[garyw]

Hi

I know this has been discussed before but my question is that I noticed that after I reconnected the 2 hoses and bypassed my hot water heater
that was leaking coolant into the bilge,  the cockpit alarm was emitting a new soft static like sound .   I am assuming this is because of the new connection I made and wonder if it reflects higher temp to the engine now that i am bypassing the hot water tank.  There is adequate coolant in the tank and from the exhaust.   I was going to check the wiring but didn't know if anyone had any other advice .   I assume this is a hot water alarm and not anything else. , eg low oil pressure which I checked with the dipstick and seemed at a good level.

Thanks

Gary W
Summer wind   
calalina 34  1986
Boston Ma

[Ron Hill]

gar : Unless a PO had installed a Hi Engine temp alarm, your cockpit alarm static might just be a coincidence.

A thought

[KWKloeber]

gary the alarm should just be coincidental.  taking the WH out of the loop should have no significance, but if you want, try to replace the long loop with a short hose between the two engine ports.

Did you bleed any air out the system after you cut/connected the coolant hoses?
You may have had air -- do you have a recovery tank - did it lose coolant?
Check your thermostat?  Opening at the temp it should?

The oil switch operates on pressure, not level -- it could be failing.  Temp disconnect it to see -- no wire, no ground connection to set off the oil alarm.

Stick your engine info in the post/signature.

ken

[garyw]

thanks

i didn't bleed the air out of the system but will check the recovery tank.

i have to go back to the boat to get the engine info but i think it is the m25
will look into the the other points you made .

i do notice that the engine is operating at a warmer temperature then before but still < 160 , just that it warms up more quickly then before i removed the hot water tank. 

gary w

[Ken Juul]

if it is getting warmer earlier, might be a failing thermostat.  I would change the thermostat and bleed and see what happens.  Boston water is always cold, should not have an overheating problem.

[KWKloeber]

Gary,

The faster-heating water is the reason that the WH (on early M-25, C-30s) was changed from being in-line with the Hx, to the WH being heated off the thermostat bypass (C-30 M-25XPs -- a "critical upgrade" for the C-30s.) 

The attached shows where the WH was 'tapped into' the thermostat bypass.  The bypass (whether a short hose or WH loop) is there to keep a little coolant circulating in the block (eliminating hot spots) while the block comes up to temperature while the thermostat is closed.  Likewise, there is a 1/8" bypass hole in the thermostat flange itself, so a small coolant stream runs through the Hx while the thermostat is still closed. It's all about a marine engine not being as efficiently cooled with a Hx, compared to a tractor w/ a radiator.

I suppose the WH being on the loop intially provides some additionally cooling, but once the WH heats up, or the thermostat opens, the WH should have no effect in the big picture.  if the temp is around 160, there should be no alarm in any event.

It's best to install the high water temp switch (on the thermostat cap) upgrade, and use that type alarm rather than relying on the water temperature gauge alarm.

You have the 3", not 2" Hx, correct?  Do you have a temp sensor on the side of the exhaust manifold?

kk

[garyw]

Thanks for the explanation and picture.   I think my wh is off the themostat bypass but will check .  Not sure about the hx size.  or whether i have a temp sonsore on the exhaust manifold.  will need to go back to the boat and look more closely.   Gary