dhmeissner
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Is this fresh water reservoir for a FL120 one that is already set up for an expansion tank? I assume made by American Diesel?
expansion tank
- Thread starter dhmeissner
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RT Firefly
Enigma
Greetings,
Mr. dh. That is your expansion tank. I understand any expansion tank (Lehman) can be converted to use a remote reservoir. I think the modification consists of a new cap and "something" in the filler throat. Can't see in your pictures with the cap on.
Mr. dh. That is your expansion tank. I understand any expansion tank (Lehman) can be converted to use a remote reservoir. I think the modification consists of a new cap and "something" in the filler throat. Can't see in your pictures with the cap on.
OP
OP
dhmeissner
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Thanks. That isn't mine, the one I have doesn't have the small nipple for the expansion tank hose. I was thinking of buying this one though, and adding my own expansion tank somewhere.
RT Firefly
Enigma
Greetings,
I think ALL the tanks have that nipple from new. Possibly, has yours been removed? Fluid used to just overflow into the bilge via an open hose when the cap released. The conversion, as I understand it, is as Mr. psneeld and I described previously.
On a previous Lehman I simply routed the existing hose into a translucent plastic jug fastened to a stringer, monitored the level and poured the AF back into the expansion tank as necessary. NOT automatic but the same process.
I think ALL the tanks have that nipple from new. Possibly, has yours been removed? Fluid used to just overflow into the bilge via an open hose when the cap released. The conversion, as I understand it, is as Mr. psneeld and I described previously.
On a previous Lehman I simply routed the existing hose into a translucent plastic jug fastened to a stringer, monitored the level and poured the AF back into the expansion tank as necessary. NOT automatic but the same process.
Last edited:
Ski in NC
Technical Guru
Getting an expansion tank with a nipple is the way to go. Most marine diesels have the expansion tank/pressure cap plumbed to the suction of the circ water pump, the Lehman does not. It is at the thermostat outlet before the HX. In this case it is even more beneficial to have a surge bottle, and have it mounted so liquid level is same or slightly above the pressure cap. If surge bottle is full, and level changes with thermal cycles, you know system is "solid". The factory tank is pretty small compared to the volume change in a thermal cycle. Surge bottle takes care of that.
Xsbank
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AD sells a kit with all you need to convert your existing. It is easy to do, just remember that when you mount the overflow tank, you will probably have to put some coolant in it someday. Don't ask me how I know.
Get the kit.
Get the kit.
FF
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That expansion tank will work just fine.
Do NOT fill it full to the brim as when the coolant gets warm it will expand and some will vent to the bilge, no big deal.
The vehicle style expansion tanks , that keep the radiator full , is done to attempt to remover all air from the cooling system.
This makes it more efficient and most car / truck mfg do make the radiator 25% smaller , to save material costs.
Boats with heat exchangers are usually created for worst case , full throttle , 90F+ water.
It is far more important to keep the coolant fresh and to clean the system with 2 part cleaner as the mfg suggests , than worry about weather the pressure cap can refill excess coolant.
Do NOT fill it full to the brim as when the coolant gets warm it will expand and some will vent to the bilge, no big deal.
The vehicle style expansion tanks , that keep the radiator full , is done to attempt to remover all air from the cooling system.
This makes it more efficient and most car / truck mfg do make the radiator 25% smaller , to save material costs.
Boats with heat exchangers are usually created for worst case , full throttle , 90F+ water.
It is far more important to keep the coolant fresh and to clean the system with 2 part cleaner as the mfg suggests , than worry about weather the pressure cap can refill excess coolant.
capt jerry
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been the done that,works fine.works just like the one on your car,as it cools down it sucks the water back into the exp. tank
Ski in NC
Technical Guru
Using the surge bottle helps keep the coolant fresh. Without it, the pressure cap "breathes" each thermal cycle, drawing in air. The oxygen in the air depletes the corrosion inhibitors, eventually corrosion begins in the cooling system. With the surge bottle, only liquid transfers on a thermal cycle, and while some oxygen is transported, it is much less. Surge bottles are a good idea where ever they can be installed.
FF
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The oxygen in the air depletes the corrosion inhibitors, eventually corrosion begins in the cooling system.
YES , but the REQUIREMENT to change out the Green stuff every two years and Pink every 5 does not change.
YES , but the REQUIREMENT to change out the Green stuff every two years and Pink every 5 does not change.
