Newmar diesel def questions

[Wayne Daul]

When viewing the Tiffin Facebook diesel discussions it is quite apparent that many have suffered the dreaded Def Shaw failure. But reviewing Newmar diesel there doesn’t seem to be anywhere near the failures. Does Newmar use a different system to use Def? Or do Newmar owners not complain all over the internet.

My major concern is my lack of mechanical ability and fixes I read on Tiffin forums is way above my comfort level.

I will be driving a Kountry Star with 360 Diesel engine.

Thank you for your response.
Wayne Daul

 

[Richpatty]

My feeling is that maybe more Newmars have Freightliner chassis, which are less prone to this issue, than Tiffin... The Newmars on the Spartan chassis have seen more than their share of issues...

 

[FloridaSon]

Agree with Richpatty,
During my research phase, this DEF sound horrible. Several NEWMAR sales people acted like it did not exist. I looked for comments and feel Richpatty is right, Freightliner seems to be more reliable. Took the Zoom Freightliner chassis class and they suggested not letting DEF level drop before topping off. Dry areas from low DEF make crystals which do not get reabsorbed when they drop off an fall to the pickup area.

 

[Neemer]

Regardless of chassis manufacturer, get yourself some cheap insurance by building a DEF sensor simulator. DEF Sensor Simulator

This little box will get you out of a potentially dangerous roadside situation should you go full derate.

 

[Rich W.]

This is a long post but its a long story, starting in 2010 when the EPA prematurely mandated the implementation of DEF systems on diesel motor vehicles. This is old, proven technology that works fine in stationary facilities such as factories and power plants, but was simply not ready for the mobile environment when forced on the driving public. So…..

A lot of confusion comes from changes in systems over the years (2007, 2010, 2016 etc) and yes, different chassis manufacturers. Spartan uses Shaw DEF heads as does Tiffin on the Powerglide chassis. But both Newmar and Tiffin also offer many coach models on Freightliner chassis. FL‘s supplier (TE Connectivity for mine) seems to have solved the problem with their DEF “Headers” (FL‘s term - everyone else says DEF head) while those using Shaw lagged a couple years behind causing all kinds of chaos and troubles. They claim they’ve finally got it right with Gen 7 or 8 - we’ll see.

The big problems are old DEF which is out of spec for the quality sensor (2016 and later) and high temperature which causes both a higher concentration of ammonia (damaging to all systems) and precipitation of salts which cause the float to hang up on pre-2016 systems as noted in the following TSB: (https://static.nhtsa.gov/odi/tsbs/2013/MC-10142383-9999.pdf).

High temps occur environmentally which is why there is a scale for DEF shelf life from over a year at around 60*f to 90 days at over 100*, but also can be due to a stuck tank heater valve. These valves fail in the open position heating your DEF to engine temp levels which of course destroys the DEF and subsequently the header. Smart design, huh? An easy fix here is to install a valve in the tank heater input line and shut it off and only open it if you are going to be driving in sub-freezing temps. They say DEF starts turning to slush at about 12* so that gives most of us a lot leeway.

Last Fall the EPA finally responded, but with a weak solution to the problem, allowing engine to manufacturers to upload a software fix to work around the problem because of an extreme shortage (using Covid as the Great Excuse) of parts but this did nothing for the stranded motorist and the restrictions placed on getting it done are just as extreme as the problem. So far I’ve read of NO ONE who has found this solution satisfactory. And of course the real problem is dependance on off-shore manufacturing, not Covid.

Diesel Exhaust Fluid (DEF) Sensor Shortage Updates | US EPA

Diesel Exhaust Fluid (DEF) Updates

www.epa.gov

Another solution mentioned above is the DEF sensor simulator (DSS). This is a much more effective work around and puts control in the vehicle owners hands, but will only work on 2016 and later emissions systems and requires some skills that are slightly above the basic level to build. The link noted above provides good comprehensive instructions for acquiring parts, building, programming, installing and testing it, but it isn’t just plug and play. But it does work and is an excellent item for coaches with 2016 and later emissions systems and my recommendation is to buld one and keep it with your spares in case you need it, and not waiting until you need it to pursue this solution.

For pre-2016 system owners, the following link is IMPORTANT and even if you can’t do this fix yourself, a shop can IF they are aware if it. This is also why they say “keep your DEF tank full” but why its only applicable to pre-2016 systems. One thing you can try if you are getting the dreaded “false low DEF” codes and facing de-rating, is to flush the tank a couple times with water (preferably distilled or very clean filtered) and then refill with new DEF. This has worked for some and avoided actual mechanical work on the vehicle. Also the image in the TSB also shows the electrical connection to the header which you’ll note is why the DSS will not help with this type of system (older analog vs newer digital parts) https://static.nhtsa.gov/odi/tsbs/2013/MC-10142383-9999.pdf

My coach is a 2016 but the chassis was built in 2015 and made it under the wire before the 2016 emissions came in to effect - another source of confusion. Pre-2106 systems just have level and temp sensors, and the sensor unit (DEF head(er)) is actually serviceable in many instances of failure. Post 2016 has level, temp, amd quality sensors, they are solid state, and the electronics in the sensor head are much more suaeptible to failure for a variety of reasons. These post-2016 sensors are also done once they fail, and failures were so high initially that a significant shortage occurred leading to waiting lists, stranded motorists, and rigs stuck at shops waiting for parts.

Meanwhile one of the most significant problems are misinforation and a lack of education for the owner/operator. Dealers don’t want to talk about it, the EPA took forever to even come up with a lame attempt to help that really doesn’t, and shops love the easy money and job security. So consumers are left to figure this put on their own.

I have read many accounts of people spending $2-3k or more for work that is actually covered by the emissions warranty. I’ve sent a handful back for a refund and all have collected some or all of their money, but imagine the countless others who were taken on this. My theory is that shops do this for two reasons: 1) it’s easier to swipe a customer’s card than file paperwork and wait for payment from the manufacturer, and 2) they can charge the consumer A LOT more for the same work than the manufacturers will pay. Yes, laziness and greed. Go figure. Meanwhile dealers pretend the problem doesn't exist because they want to sell coaches, and because a lot of them don’t understand the vehicles they are selling.

So the moral or this story is to learn your vehicle, understand the emissions system for your model and year, know your warranty, and don’t take an unsatisfactory answer at face value. Get a code reader, preferably one with some basic emissions commands, and verify everything before handing over big bucks for repairs.

The article below gives a good explanation of DEF and also reminded me of another debate: pump (bulk) versus packaged DEF. Since the coach DEF systems have proven fragile, I only use packaged DEF with a decipherable date code for my coach, and this is my recommendation for anyone with a diesel RV, regardless of the manufacturer. My 2017 Ford F250 seems to be much more robust so it can use pump DEF. I also don’t depend on it as my domicile many miles from home.

Diesel exhaust fluid - Wikipedia

en.wikipedia.org

A parting comment, then I’ll stop editing and updating all this: none of the DEF components or issues have anything to do with your DFP and regens (passive, active, or parked/forced) as DEF is introduced to the SCR AFTER the DPF. I’ve both experienced and read of instances where a shop tech will reccomend and/or perform a forced regen when faced with DEF head(er) codes, and then charge for it. Regens wont help with DEF issues, and DEF issues wont cause DPF problems so it’s important to separate the two when dealing with emissions related fault codes.

 

[Rich W.]

To the OP. since you are driving a KS 360, you must own a 2020 or later coach built after FL and TE Connectivity (or some other supplier) got their respective acts together and started supplying units with reliable DEF headers.

So just keeping fresh DEF in it, using box DEF and understanding the date code, and not letting it sit for months at a time in hot weather with a 1/2 tank of DEF will serve you well.

Another other helpful item is owning and using a refractometer to test DEF when in doubt (or every time to be completely safe) so that you’re always putting in DEF that will satisfy the quality sensor.

One other item on DEF that I forgot to mention above is the DEF fliter. The published maintenance interval can be anywhere from 150-300K but that is a chassis spec for a class 8 truck, and doesn’t take into account the way an RV is operated, or not operated in this case. If you drive every day and log over 100,000 miles per year, your DEF filter is always wet (even though its pumped out every time you shut down) and will probably last that long.

But if you let it sit for months at a time, you can easily imagine the filter sitting dry, salts precipating out, and it becoming plugged up with that white, crystalline crud that you see around your tank filler and anywhere else DEF is allowed to evaporate. If this happens enough, the filter will clog and the pump will will strain and wear out prematurely, or your system will plug up, both conditions causing errant “low DEF” codes.

Unfortunately there are no specific codes for “low DEF pressure” or ”DEF pump failure” but instead it will just throw a “LOW DEF” code because an insufficient quantity is reaching the doser, leading of course to derate. This happened to me and naturally I suspected another DEF header failure, and it was a real head-scratcher for the tech at FL until he figured it out.

So to prevent this my reccomendation is to change your DEF filter annually regardless of milage, or even because of low milage. It is an easy, cheap job anyone can do, and it is one more thing to help prevent becoming stranded by your emissions system.

 

[Texas Clodhopper]

Rich, I have a 2017 Ventana 4369, where is the filter located and what does it look like?

 

[Rich W.]

Rich, I have a 2017 Ventana 4369, where is the filter located and what does it look like?

If its Freightliner, and maybe also for Spartan, the filter is located on the pump, behind the round cap on the center/right side of the pic. The pump (called a DEF Supply Module) is usually located at the bottom rear of the tank (facing the filler neck). The filter is available for around $60 if it says Bosch on the box, or around twice that if says Cummins (also Bosch). Having already experienced a pump failure, I carry a spare. Here’s a link showing a Bosch filter for about half price:

1457436033 Bosch Urea DEF Fluid Filter - Diesel Pro

1457436033 - Bosch DEF Fluid Filter Kit. UF101, 68087337AB, DZ114640, RE554498, 2888182, 3955034, 5303604, 21516231, 23381558, 21376699, 21496421, 21673818

mydieselpro.com

Your part# may be different of course.

 

[Texas Clodhopper]

Thanks, I should have identified that it's a Freightliner chassis.

 

[Rich W.]

As a disclaimer I haven't read anywhere that anyone agrees with my findings, or is proposing annual filter changes, unless you drive 100,000 miles/year.

But I had a pump fail on a rig that was only four years old and only had 26k on it at the time. It was still under the emissions warranty which was nice financially, but that didnt keep me from having to return home, cancell all my Christmas/New Years holiiday travel with family, and wait over a month for an appointment at Freightliner.

So this is all school of hard knocks stuff and not research or the advice of techs or the result of a seminar or whatever. But I figure for the cost it’s cheap insurance and my passion about these emissions systems starts and stops with avoiding ever being stranded by the complexity and fragility of them again.