refilling coolant and bleeding crusader 7.4 XL?

[davolson]

I am the new owner of a 1994 3100 open. I have found that i need to replace the water heater. (That would be a separate longer post).
When trying to check/repair/remove the existing 6 gal, i ended up wet vac'ing, and losing probably two gallons of antifreeze to the bilge and wet vac from the "inboard"
heat exchanger pipes on the back of the water heater.
I've ordered a new water heater.. but am not sure how to add the missing antifreeze to the engine. Do i need to bleed somehow with a loose radiator cap? Or, can I just open and keep filling the reservoir on the top of the engine. How long will it take for the air in the system to dissipate? Just check it and fill the reservoir after the engine comes to temp, or is there a better "procedure" to follow?
Thanks for the help!
Dave O

[Uhehner]

On my '88 with 454 Crusaders after a riser replacement I would just remove the heat exchanger radiator cap and top it off. Bubbles would come up. Then when I started the engines, the level would drop when the thermostat opened and I would top it off again. My final top off would be after an extended run. You will be at it forever trying to refill through the expansion tank. Capt. George

[davolson]

Thanks George... I was going to do that, but have rear exchangers.. with no radiator cap on them. Assume I will just fill the riser cap that is more forward on the engine, although I dont think that is a "high" point" in the system for air to bubble to.

[ReelNauti]

The cap shoud be on the engine block not the exchanger.

Take a look at the top front of the engine.

[GCAT9110]

Obviously you have a engine coolant heat exchanger/radiator. If you lost 2 gallons +/- you should start with a cold engine, remove the radi cap, add a gallon and let the level come up but remain well below the radiator cap rim. Start the engine and let it warm up, it will eventually burp and the air will bleed out then the coolant will seek its own level, add as you need and top off while the engine is hot. Install the cap and run the boat under load, any excess will dump to the the reservoir. Pull the cap and check the level again once the engine has cold soaked.
Frank

[davolson]

thanks all for the help. I appear to have finally got things full w/o any airlocks. Took about 4 cycles of bringing the engine to temp, filling, cooling, filling again, but the temps are now stable under load and not taking anything from the reservoir.