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fagnaml

"DEF Head" Education Please

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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!

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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.

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It seems the higher percentage of failure is with Spartan. They are using a DEF head manufactured by Shaw, FTL uses a different mfg. 

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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. 

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17 hours ago, 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). 

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I just read on a different forum that Spartan will only ship a DEF head if you have derated and engine is now shutdown. A poster has a 2018 Dutch Star and has 4 DEF fault codes but Spartan will not ship her a DEF until she gets the red light. Spartan told her to drive it until it shuts down. She just left Pagosa Springs and is not excited about crossing the Rockies with a good possibility of  a shutdown ascending or descending 6-8% grades. 

https://rvforums.com/threads/otr-diagnostics-def-derate-faults.6326/

Edited by elkhartjim

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20 minutes ago, manholt said:

She going over Wolf Pass?  That's a huge safety issue!  🤬:(

Thats her concern. What the heck if the red light comes on and the engine shuts down?  Best scenario is she is in a climbing lane, otherwise she could completely block traffic. 

Unfortunately, I can see a class action lawsuit in the offing.  

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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. 

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My previous motorhome on FTL chassis did that once to me and your correct, maybe 5 seconds but felt like it was instantaneous. I had some warranty work done on the cooling system and they didn't get the the sensor for the coolant overflow tank in securely and when it finally fell off it showed no coolant and shutdown. 

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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!

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Her yellow light has been on for at least 5 days. The following is an interesting read but just because its on the internet, I ain't beleiving it.

"I've been reading up on the DeRate aspect of a DEF Header failure. It appears that some OEMs have reached an agreement with the EPA to allow an Emergency Authorization Override that allows the DeRated vehicle to operate without the DEF system for a period of time. There is some reporting requirements but that sure beats sitting on the side of some roadway in "who knows wheresville".

Also, Cummings/Freightliner appears to have either a reset or override triggered by a series of key turns and power resets that may help some get to a Service Center without a tow.

Happened across this on the other forum:

"Anyway... that night, I put the key to the left for two hours as suggested by Freightliner who said that sometimes clears the codes. In the morning, per a youtube video, I shut off the chassis batteries for 15 minutes. I also unplugged and turned off the house batteries for good measure. After 15 minutes, I turned the key to the right halfway not starting the engine. I let the system power up for 15 seconds or so and turned the key back off. I repeated that procedure 4 times and then started the engine. I still had the red stop engine light on and I assume I was still d-rated. I let the engine run a while... I'll guess at least 5 minutes. It sure seemed like a long time. After a couple of minutes, the flashing red low def level light went off and the gauge read correctly at 3 green bars. After several more minutes, the Red stop engine light went off and the system was normal. Excited to avoid a tow or a mobile tech, I started the 41-mile drive to Velocity in Tucson. After 10 miles, the orange service engine light came on and the DEF level flashed red, and it remained so the rest of the way. ....."
 

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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 by fagnaml

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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.  

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Carl, she contacted NIRV yesterday and got Brett Davis involved, Spartan is shipping her a DEF head today. Do you think it had anything to do with her having a 2022 London Aire on order with NIRV?  I understand the DEF head cost is now almost $900. plus installation. 

 

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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!

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6 hours ago, 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

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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 by jleamont

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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 by Sreecer57

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Yes!  Call Freightliner (they are certified to work on Powerglide chassis).  DEF is a chassis part, not manufacturer!

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