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[Neal]

24/7 Direct | Customer Support from FCCC RV

Freightliner Custom Chassis is the only chassis builder to offer around-the-clock toll-free support for the life of your coach – not just the warranty period.

www.fcccrv.com

 

[Rich W.]

The valve that controls the DEF tank heater is prone to failure and when it fails, it fails in the open position, over heating the DEF. This really matters because DEF starts to break down far below the operating temperature of engine coolant. Since DEF doesn’t freeze (turn to slush) above 12°F and you probably don’t drive the coach in those conditions, you really don’t need a tank heater - its designed for comercial trucks that have to run in those temps.

The quick cheap way to deal with it for an RV is to stop the flow of 190°+ coolant into the DEF tank heater by using a double male barbed fitting to connect the DEF tank heater hose lines to each other externally, by-passing the tank heater. This would only become an issue when driving around in sub 12° temps. If you want the heater to still function you could install an external valve on the input side instead of the double male and operate it manually as needed.

 

[Jim]

The quick cheap way to deal with it for an RV is to stop the flow of 190°+ coolant into the DEF tank heater by using a double male barbed fitting to connect the DEF tank heater hose lines to each other externally, by-passing the tank heater.

You wouldn't happen to know where this DEF tank heater is located would you?

 

[Jim]

24/7 Direct | Customer Support from FCCC RV

Freightliner Custom Chassis is the only chassis builder to offer around-the-clock toll-free support for the life of your coach – not just the warranty period.

www.fcccrv.com

That is almost impossible to believe! There must be millions of Freightliner trucks on the road! How can they offer free, 24/7 support to all those owners?

That's really incredible.

 

[Neal]

That is almost impossible to believe! There must be millions of Freightliner trucks on the road! How can they offer free, 24/7 support to all those owners?

That's really incredible.

This is Freightliner Custom Chassis => RV's

FCCC is Gaffney, SC

 

[Neal]

This is who I called on Labor day when I derated in Breckenridge, and they helped me even on the holiday.

 

[Jim]

This is Freightliner Custom Chassis => RV's

FCCC is Gaffney, SC

Ahh, got it!

 

[Rich W.]

You wouldn't happen to know where this DEF tank heater is located would you?

The valve in question is right on top of the DEF header on the top of the tank with a two wire plug going to it (red and blue IIRC). You can unplug it and test the ohms across the valve terminals - should be around 12 ohms and if its bad it will be a lot more (thousands) so its easy to check. The valve has a heater hose attached to it and the return line comes out of the DEF header adjacent to the valve. Its obvious once you know what you are looking for. I would guess 5/8 or 3/4” hose. The two protected small lines are DEF supply and return.

Caveat: I’m assuming since your coach is a 2016 that the chassis was built in 2015 and thus to pre-2016 emission specs. Everything changed for 2016 and later emission systems. This makes a difference in several key areas, the tank heater valve being one of them.

My chassis was built in May of 2015 and the coach was built between Dec 15 and Feb 2016 making it a 2016 with 2015 emissions.

 

[Rich W.]

This is who I called on Labor day when I derated in Breckenridge, and they helped me even on the holiday.

They helped me on Christmas Day 2021 when I had a DEF pump failure. The trip was ruined but it was nice talking to a qualified person when stranded in a church parking lot on Christmas day

 

[Chuggs]

Dang Rich…you got that DEF thing down. If I run into problems…hope I can call on you.

I have a 2016 built in 2015 as well…. Guess at some point I need to school myself better on the DEF System.