Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 25, 2025 ...

anti freeze for AH

December 03, 2017, 04:23:23 pm

We've been on the road since first of October and have had the Aqua Hot on with both switches heating since then. We will be encountering a cold spell soon, so I wanted to check the level of the AH antifreeze. I couldn't see ANY level thru the holding tank in daylight, so I fired up my trouble lamp and was able to see that it was about 2 inches above the " cold full " mark. I have been reading past posts regarding antifreeze on the forums and looked in the owner's book, but must ASSUME that I should be at the  "hot full " mark. IF that is true, then I must ask HOW DO YOU ADD ANTIFREEZE TO THE TANK?? I only have 2 1/2 inches of space above the fill cap. I cannot put in a small funnel. I guess I can find a Harbor Freight and get a siphon tube?? but......is there an easier way that I am overlooking??  Thanks for your help. Happy Trails........

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Re: anti freeze for AH

Reply #1 – December 03, 2017, 04:31:07 pm

Fill them all the time with a syphon pump from a local hardware store.  There are other pumps at Harbor Freight too, all very low cost.

Fill the heater coolant tank lipping full, install good 13 lb radiator cap, get a new one at auto parts store if unsure of cap sealing ability.  When burner comes up to temp and cycles off, fill over flow tank to Hot Line.

Over flow tube should be soft and supple, not hard and brittle, with clamps at radiator barb and tank barb.  If your over flow tube goes to the top of the tank, make sure the straw that is under the fitting is in place and not fallen loose into the tank.

Hope this helps you.

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Reply #2 – December 03, 2017, 07:34:22 pm

Thanks, Rudy
I'm not sure what you are saying in the second paragraph.....lipping??? Where do I install the new cap? Inside where the heater is??
You say to wait til the burner comes up to temperature ? Should I run hot water until the heater "fires up??" Not quite sure what I am to do, but am grateful for your response.

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Reply #3 – December 03, 2017, 08:41:19 pm

The radiator filler neck and radiator cap are located on top of the heater in the area which you described as very low clearance.

Fill the heater tank through the radiator filler neck till it overflows, lipping full.  Close the heater tank with the radiator cap.

Turn the diesel burner switch on.  Most times it will start. When the burner cycles off, fill the over flow tank to the hot line.

If you turn the diesel burner on and the burner does not fire due to the coolant being up to temp (not likley if you have added coolant to the tank), then with fill over flow tank to hot line.

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Reply #4 – December 03, 2017, 08:46:18 pm

I think
Rudy is talking about the radiator cap that is on the aqua hot itself. If the unit is up to temperature be careful when you take the radiator cap off as like removing a radiator cap on a car that is hot.

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Re: anti freeze for AH

Reply #5 – December 03, 2017, 09:16:11 pm

For the overflow tank to work properly the aqua hot tank needs to be full to the top.  If the aqua hot main tank is low in antifreeze you will not get the correct expansion and contraction of antifreeze into the overflow tank.  When hot, the overflow tank should rise to hot.  When cold it should drop down to cold.  Watch your overflow tank during aqua hot operation and cool down.  If the level does not move up and down and stays at the same level, then the aqua main tank is too low on antifreeze.  The process works the same way on your engine overflow tank.  If your overflow tank is difficult to see the antifreeze level, remove it and give it a good cleaning, reinstall it, then refill it.  As far as filling, I pour antifreeze into a 16oz water bottle and then pour it into the overflow tank without any problems.
John M.

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Reply #6 – December 03, 2017, 11:44:42 pm

Thanks for all the good response!! Very helpful, once again.

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Reply #7 – December 04, 2017, 12:52:14 am

My aqua hot tank has green coolant. I thought there was only the pink. I didn't fill it so I am not sure what to put in it. Safe to assume it is the older style green? Any way of testing?

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Reply #8 – December 04, 2017, 07:51:10 am

David,

Until Aqua Hot started using the electronic control board, the coolant was engine coolant, i. e., green or what ever you put in the main engine.  Later models required GRAS (Generally Recognized As Safe) boiler fluid.

The lable on the Over Flow bottle will state the need for boiler fluid.

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