Leaking Coolant under Aqua Hot

[jimboland@sbcglobal.net]

My motorhome is leaking what appears to be coolant dripping out from under the Aqua Hot unit.  It is not anti freeze from the Aquahot, I am assuming a coolant line from engine area of motorhome toward the front is leaking.  I cannot see where the fluid is coming from.  Any thoughts or ideas on what/where it may be leaking from? Is there a coolant line that extends to front of the motorhome from the engine area?  I have attached two videos showing the leaking.

Thank you,

Jim Boland

2009 Monaco 42kfq

[vito.a]

The Aqua hot has two heater hose sized coolant hoses that come from the engine.  They are used to preheat either the engine, or to heat the Aqua Hot boiler when driving.  

You'll have to remove the Aqua Hot cover to access them.  

[Donflem]

I would think it would have to be something with the Aqua hot it looks like it’s right under it there are a few lines coming out of the AH going to all the heaters. I had a leak like that all I had to do was tighten a hose clamp. Good luck it looks like a mess.

Don

[Jdw12345]

At that rate it shouldn’t be too hard to figure out where it coming from, imo.

[georgecederholm]

In the first video, the drippage looks rather brown, so it might be boiler fluid rather than engine coolant. There are a lot of hoses involved, 2 for each furnace zone circulation and two for the engine pre-heat (supply and return for each). Most of them connect to stubs or elbows originally supplied by Aqua-Hot, so up to 4 hose clamps per line, plus connections inside the Aqua-Hot box at the circulation pumps. If the original constant-pressure clamps have been replaced with regular hose clamps, they can need tightening periodically. 

From where it seems to be leaking, I’d recommend starting by removing the Aqua-Hot cover to access the burner and internal connections, and see if anything can be found there. Since all of the zone and engine preheat line tend to run away from the unit, they would be less likely to leak down through the unit as the video appears to show much of the leak coming out near the hole in the floor that acts as the furnace air intake.

One last thought based on the original question: if the leak is actually engine coolant, then there are actually 2 additional hoses that run from the engine to the dash heater and will pass right over the Aqua-Hot on the way forward. I think those aren’t the likely culprits because there shouldn’t be any splices in that area and it would be tougher for a leak to work its way into the Aqua-Hot box.

[zmotorsports]

As Vito suggested above, it can be either boiler fluid (glycol) from the Aqua-Hot unit itself OR engine coolant from the engine pre-heat loop if your coach is so equipped.  I believe most Monaco coaches that are equipped with the Aqua-Hot option do have the engine pre-heat tied in from the factory.  Some other manufactures it seems to be hit and miss as some didn't utilize that option from the factory for some reason.  Tiffin in particular I've seen about 50/50 have the engine loop.

 

You will need to at minimum remove the upper cover and it will be easier to remove the lower cover as well as the engine pre-heat hoses are located at the bottom of the cabinet.  With that size leak it should be fairly evident where you problem lies.  If it is not the engine coolant loop then start looking at the boiler side but I've seen and read multiple issues with the heater hose rubbing through on Monaco coaches creating an engine coolant leak just out away from the cabinet.  When I replaced all of my hoses about 8 years or so ago mine had been wearing a spot that was ready to fail so I caught it in time.

 

If you determine it is Aqua-Hot boiler fluid, then look at main lines first before branching out to zone lines. 

[jimboland@sbcglobal.net]

Thanks for all the help.  It was leaking from the engine coolant lines located to the rear of my Aqua-Hot unit for the pre-heat system.  Gained access to them through the panel in my storage compartment.  Very tight area.

[Donflem]

Glad you got it sorted out what a mess.

Don