Charging Coolant Lines?

[albinalaska]

Good morning,

As part of a rather involved refit of our engine room I've traced a nuisance leak from my boats old busted/rusted water heater (originally the leak was thought to be water from the tank but was actually found to be coolant from the Port engine).

The water heater needed to be removed/replaced but in doing so I had to cut the coolant lines leading from the engine (FL120) which, of course, took some time to clean up but now I'm not too sure what is involved with fixing it once the new heater is installed.

Any advice on steps or operating procedures for getting the coolant lines charged or what to look for or be careful of/avoid would be greatly appreciated! For example: I read that cutting the line might introduce air into the system which is bad?

As always, thank you kindly!

 

[kchace]

When I replaced my HW Heater I didn’t do anything special to the Lehman 135 attached to it. Just refilled the Coolant and topped up after running it a while. Everything worked as it should.

Ken

 

[Comodave]

When I replaced my HW Heater I didn’t do anything special to the Lehman 135 attached to it. Just refilled the Coolant and topped up after running it a while. Everything worked as it should.

Ken

+1. I replaced the hose on my SP225 last year and didn’t do anything special.

 

[catalinajack]

Just run new hoses from the source and return. You already cut them. Since you do not know their age now is a good time to update with new. Or, you could eliminate the engine heat option completely. Some guys on this forum are not fans of the engine heat option. If your heater has this option the ports can simply be capped.

 

[Lepke]

Add valves to the lines so you can isolate the engine if a new leak develops.

 

[BDofMSP]

Add valves to the lines so you can isolate the engine if a new leak develops.

Would you really need to put a valve on the return side too? Wouldn't stopping the feed be enough?
BD

 

[DavidM]

I once installed coolant lines to the water heater on a Mainship 34T. At first while running at the dock the water heater loop didn't fil, stayed cooll and was air locked.

I asked what to do on boatdiesel and they told me to take it out with the coolant filled as far as possible and run it moderately with the cap off. If the coolant level dropped that was good (the air was pushed out), but top it off and run for a little while longer. Then feel the water heater loop for heat. I did that and felt that the lines were now warm and put the cap on and all was good from there on out.

David

 

[HiDHo]

I replaced the water heater, engine loop hoses and drained and filled the engine with new anti freeze solution all at one time with no problems.
IMHO I like the engine heating the water tank most times cruising the electric is turned off to the water heater because the engine supplies plenty of heat.

 

[AusCan]

Would you really need to put a valve on the return side too? Wouldn't stopping the feed be enough?
BD

You'd need two valves to isolate the tank. (flow can come from either direction if there is a leak in the tank). I have a third for a bypass valve which I open if the two isolation valves are closed.

 

[Nomad Willy]

The trick is to fill the cooling system VERY SLOWLY from the highest point. On our boat that’s under the settee but the buss heater.
My boat is plumbed w gal. steel pipe at that point and there’s a pipe cap on top of a vertical pipe. I take off the cap and VERY SLOWLY pour my 60/40 mix of distilled water and AF.
It’s best to be doing something else as you pour small amounts mixed coolant into the top of the system. When it’s finally full and dosn’t drain down for several minutes.
Start the engine and stop it when there’s burping from your fill point.
There will be a point where larger amounts of coolant is needed. Feel the coolant hoses and pipes (if you have them) and slowly you will fill the whole system and purge the trapped air.

Watch and otherwise monitor the engine for awhile. And otherwise after keep track of what the system does and dosn’t do so over not much time you’ll know what’s normal.

 

[Ski in NC]

Just hook it up as normal, fill and run engine, rev up a bit to say 1200. Check temp of hoses to water heater by hand. If they warm up with the engine, coolant is circulating and you should be good to go. If they stay cold, pump is air loaded.

Always want to keep an eye on coolant level for the next few thermal cycles.