fagnaml Report post Posted June 22, 2021 Seems like I revert to Motorhome 101 class more often than I'd like. The iRV2.com forum has a new, very lengthy discussion about "DEF Head Failures" which per the discussion starts happening after about 15,000 miles of use and mostly on Spartan chassis. After reading this long discussion, I started to wonder / worry about the DEF Head on my coach which has a Freightliner XCR chassis that has 14,800 miles of use. Thus I'm turning to the experienced professors of FMCA for some basic education: 1) Do DEF Heads used by Freightliner have the same failure rate as DEF Heads used by Spartan? 2) Should a DEF Head be proactively changed at some mileage / age frequency? 3) Should a new, spare DEF Head be part of the "critical spare parts" inventory I keep (at the moment I only have spare fuel filters and spare slide-out controller)? 4) Do I need to worry about my DEF Head failing during a journey this weekend to San Antonio (wife and I are taking two of our younger grandkids to Sea World to give their parent some time alone)? Thanks for your thoughts and guidance! Share this post Link to post Share on other sites
manholt Report post Posted June 22, 2021 Hi Mike! Enjoy San Antonio. You have a 2nd or 3rd generation DEF, they seem to last about 70, 000 miles on avg. The ones that go out at 10,000 to 25,000 miles are the 5th or 6th generation heads...chassis has nothing to do with it. Now they are on 3 month back order! Carl C. Share this post Link to post Share on other sites
manholt Report post Posted June 23, 2021 Some extent that's true. The rigs that are heavy and have big HP engines are on Spartan chassis, not FLC. IMHO, Mike does not have a foreseeable DEF issue. Share this post Link to post Share on other sites
jleamont Report post Posted June 23, 2021 On 6/22/2021 at 9:24 PM, fagnaml said: Do DEF Heads used by Freightliner have the same failure rate as DEF Heads used by Spartan? YES. It really depends on how low you run the DEF, and most of all EXPOSED CLIMATES. The colder the more frequented failures. Each manufacturer has had their problematic years. I have had Bosch units identical fail in 2019 more than the exact ones made in 2018. And when I say fail, I mean every 6000 miles your getting towed in. Eventually the manufacturer corrects the issue and they’ll last MAYBE 80,000 at that point, some just go longer for no reason. DON’T FORGET, there is a filter at the bottom of the tank that requires annual replacement. Depending on how/where your tank is mounted it could be a pain to access. It will clog just from being submerged, not so much of an issue with how much DEF flowed through it (like a fuel filter). Share this post Link to post Share on other sites
manholt Report post Posted June 24, 2021 She going over Wolf Pass? That's a huge safety issue! 🤬 Share this post Link to post Share on other sites
jleamont Report post Posted June 24, 2021 Jim, always been that way with the shut downs. All manufacturers blame the government mandated rules. Freighliner shuts you down with only a few second warning and it’s like someone shut the key off. We have had subsequent damage caused by the abrupt shut downs. Think about it; Hot turbo pulling a hill, light pops on and in a few seconds the engine stalls. Share this post Link to post Share on other sites
manholt Report post Posted June 24, 2021 On the Spartan, you get a yellow light first and it say's "DEF shut down in 5 minutes", then the red light and your retarded to 5 mph for 15 minutes! That's enough to clear traffic & allow engine cool down! Dutch Star comes on FTL chassis with the 450 HP, or Spartan with the 500 HP Option! Share this post Link to post Share on other sites
fagnaml Report post Posted June 24, 2021 (edited) Thanks for the prompt responses! My interpretation of the responses is for my coach a DEF Head failure is not a big concern -- correct? Jleamont -- Your comment about annually replacing a filter in the bottom of the DEF tank is the first I've heard of this maintenance need. I don't recall seeing any discussion on FMCA or iRV2 about replacing a DEF filter. The Lube Zone business I have used the last two years for my annual oil & filter changes, chassis lube, etc. has never mentioned nor recommended a DEF filter change. You stated that DEF tanks have a filter on the bottom of the tank. Mr. Bing search for images of a Freightliner Custom Chassis DEF tank doesn't readily show the tank having a bottom filter --> freightliner custom chassis DEF tank filter - Bing images And my Freightliner Custom Chassis Maintenance Guide doesn't mention changing a DEF filter. Can you and other forum members share additional info about a DEF filter and filter change frequency for my Freightliner XCR chassis? Edited June 24, 2021 by fagnaml Share this post Link to post Share on other sites
manholt Report post Posted June 24, 2021 Jim S, when my series 1 DEF went bad at Buckhorn RV Resort in Feb 2021, it did to me as described above! When I called Spartan, they informed me that my 1 was replaced by Series 5, I had it in hand the next day, UPS, cost me $684 + installation! Never asked me the color of light. Share this post Link to post Share on other sites
hermanmullins Report post Posted June 24, 2021 I may have been she said. "Sip me a DEF head NOW or cancel the order for my coach and return my deposit NOW!" Herman Share this post Link to post Share on other sites
manholt Report post Posted June 25, 2021 Jim S, don't think so. Supply comes in spurts and I think Spartan has 2 parts bins...one for you and one for dealer. NIRVC has pulled some rabbits out for me, when no one else could help! Share this post Link to post Share on other sites
wildebill308 Report post Posted June 25, 2021 On 6/24/2021 at 7:42 PM, elkhartjim said: she contacted NIRV yesterday and got Brett Davis involved That was a smart move. Brett is interested in making customers happy. Also if she is going to trade her coach in it is going to halve to be fixed any way. Bill Share this post Link to post Share on other sites
jleamont Report post Posted June 25, 2021 (edited) Mike, if it’s not equipped I’d be shocked/concerned. Here is a link to the most common on smaller engine medium duty. It’s service interval is 1 year or 150,000 miles. I’d call Gaffney to verify the part number. https://www.bigmachineparts.com/products/baldwin-filters-def-filter-pe5272 Jim, Freighliner trucks have a switch on the dash labeled “fault OVR” you press the button and hold while cranking the engine it will allow you 15 minutes to get to a safe spot. Sometimes it works, sometimes it doesn’t. Edited June 25, 2021 by jleamont Share this post Link to post Share on other sites
Sreecer57 Report post Posted July 16, 2021 (edited) Is the yearly filter chg maintenance also for the Powerglide chassis on our 2011 Allegro Bus. We are dead in campground. Code says Def Head sensor which Tiffin says they don’t have. Edited July 16, 2021 by Sreecer57 Share this post Link to post Share on other sites
manholt Report post Posted July 16, 2021 Yes! Call Freightliner (they are certified to work on Powerglide chassis). DEF is a chassis part, not manufacturer! Share this post Link to post Share on other sites
