Murphy Swichgauge

[racclarkson@gmail.com]

Talking to a guy today that has ran numerous boats suggested I install Murphy gauges such as these on my Detroits to warn me if the coolant level drops. Anyone have them on their boat and if so where are they installed, experience with them, etc? Was suggested to me to install to monitor coolant level in tank with an external alarm. Thus if coolant level drops due to leaking or busted hose you would know before engine overheats. Sounds like a good idea and they are only about $100 bucks each. I was thinking of mounting on engine room bulkhead and piping over to the coolant tank. They also provide a visual gauge so you dont have to stick your finger in the radiator cap to check levels as you do on mine which are inches from the ER ceiling

Couple of thoughts.

Do you have expansion/surge tanks? If you do then you always know your heat exchangers are full when the coolant is returned when the motors cool down. If the coolant is not flowing back, that may be an early warning sign of an internal leak.

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If you do have expansion/surge tanks, why not use a sensor there? What about a non contact sensor?

[Briankinley2004]

I have them but mine are metal and mounted on the side of engines. they have a small clear tube.One has coolant in it about half way up and the other has never backflushed into the tank. Not sure why but it hasn't. My understanding is the Murphy gauges are more to indicate a loss of coolant underway not coolant levels in general. So if you are on a day trip and you bust a hose it will sound the alarm before the engine loses enough coolant to get hot and do damage. Thats the way it was explained to me. Im still ciphering on it as us hillbillies say

[racclarkson@gmail.com]

I have them but mine are metal and mounted on the side of engines. they have a small clear tube.One has coolant in it about half way up and the other has never backflushed into the tank. Not sure why but it hasn't. My understanding is the Murphy gauges are more to indicate a loss of coolant underway not coolant levels in general. So if you are on a day trip and you bust a hose it will sound the alarm before the engine loses enough coolant to get hot and do damage. Thats the way it was explained to me. Im still ciphering on it as us hillbillies say

I'd start ciphering on that one that don't back flow. If you bust a hose, the first thing that'll happen is the system will try and replenish itself from the expansion tank (assuming it's working properly). An alarm at the tank would offer more protection than farther downstream, would it not?