2021 Aria 4000 Losing Antifreeze

[Jsmith1243]

So i have had our Aria for a year now. We enjoy it and have had the usual minor issues to work thru, nothing really worth mentioning of value. But we just completed a trip from KY to FL and had a strange occurrence with the coolant level on the trip.

We made it to the ATL area on the way down and the check engine light came on and low coolant message, checked temps of course, all is good. I pull over and the coolant is just down to the minimum line so i keep going and keep an eye on the temp because i have no antifreeze on hand or distilled water. I drive thru ATL traffic with no issues at all on temp, stop at the fuel center, they are out of antifreeze of course so i check the level and it hasnt moved. So i just proceed on the trip to Florida. When we get there the level is the same. I do run the engine and check hoses for leaks and cant find even a drip.

Go to walmart get antifreeze and fill it up about 1.5 gallons before the return trip.

We make it to somewhere in SC on the way back, check engine light returns, with low coolant message. I pull over again and the level is back down to the minimum, i am beside myself at this point so i again check for leaks and can find nothing. I get more antifreeze and put in another 1.5 gallons.

Light goes off we make it to NC light returns, you get the picture, fill it back up...

My question is has anyone encountered this before? I see there is a procedure of filling the coolant listed on the back hatch, but we have put 10k miles on the motorhome with no issues before of overheating at all. Temp stays a consistent 190 ish.

The only thought i had was if the dash air has lines running to the front with a heater core that would have air in them but still 4.5 gallons seems to be alot. None of it makes alot of sense but figured i would ask on here before i started tearing things apart out on the driveway in the cold.

 

[ghnl]

Freightliner Chassis? DEF system? Are there any connections between the coolant & the DEF system?

 

[Jsmith1243]

That would have been a good thing to include in the original post, i apologize. Yes its a freightliner chassis, cummins with a def system. I will have to look to confirm about if there are connections between the def system and the coolant system, im unsure.

 

[Lt Keefer]

Never owned a diesel but anytime antifreeze disappears without a visible leak my first thought is blown head gasket.

 

[DVisger]

Thor Aria 4000 owner here, recently had a similar problem. While driving would lose antifreeze down to the minimum level. Fill up antifreeze in driveway didnt notice any leaks. Figured out it was leaking from the lower RH side of the radiator when it heated up when driving. After driving it would cool down and stop leaking. Finally noticed some drops on the driveway and wetness in lower RH corner of radiator. If you have the same problem, radiator still should be under warranty.

 

[simidrm]

Yes there is a connection between the def and antifreeze, inside the def tank is a heater that has coolant going it, but if it was leaking into the def tank you would obviously over fill the def tank but would also through a fault code for def quality, if I had to hazard a guess I would look at the egr cooler as they tend to have a lot of failures which let coolant into the exhaust and then get burned up in the heat , which will eventually ruin the dpf filter.

 

[Jsmith1243]

I was able to look into the issue this weekend and discovered the leak was coming from the ProAir unit in the front of the coach. Appears to be the heater core as all the hoses and connections look good.

I attempted to take the ProAir unit apart and then stopped after noticing its nearly an impossible task with fasteners going in from both sides of the firewall. Has anyone ever successfully changed the core on these units? It appears ProAir has gone out of business, i saw a few parts stores online but not much info on how to take it apart.

The only thought i had was to take a grinder to the case, as it doesnt appear you can even get access to the screws from the dash side of the coach, the bottom screws are lower than the floor of the coach...

 

[HMCSW]

I was able to look into the issue this weekend and discovered the leak was coming from the ProAir unit in the front of the coach. Appears to be the heater core as all the hoses and connections look good.

I attempted to take the ProAir unit apart and then stopped after noticing its nearly an impossible task with fasteners going in from both sides of the firewall. Has anyone ever successfully changed the core on these units? It appears ProAir has gone out of business, i saw a few parts stores online but not much info on how to take it apart.

The only thought i had was to take a grinder to the case, as it doesnt appear you can even get access to the screws from the dash side of the coach, the bottom screws are lower than the floor of the coach...

Check Frieghtliner warranty, depending on in service date you might be covered.

 

[DaveB1]

Not sure if you want to consider this option but there is a Cummins approved leak sealer which might solve the problem. I used it on a previous Palazzo with good results and it did not plug up the heater core but stopped the leak.