DEF problem

[Dutch Star Don]

It seems that most of the reported DEF head issues that flooded the forums have disappeared. The majority of the issues were with the Shaw head used on the Spartan chassis. It was also used on the Tiffin chassis. There were very few reports of a Freightliner having an issue. Back during the height of Covid and no quick repairs for DEF head failures, I actually bought my own DEF head and stored it in the coach before a month-long trip.'

Later, I made one of the DEF defeat modules. Mine will fit a Freightliner or Spartan chassis. Now, the government is allowing the bypassing of the DEF system in an emergency and DEF heads are more readily available.

To answer Neal's question, I've never seen a report where DEF fluid was the actual issue. I buy my DEF at Walmart and just add as needed. We don't burn enough DEF to deal with buying it at the pump. We rarely use truck stops for fuel, Th only issue with store bought DEF, especially at Walmart, someone could buy a jug, use it and then return it with water. Whenever I'm suspicious, I use a refractometer to check it.

 

[Richpatty]

Great thread…. I read with interest since as I also debate whether to:
- only fill DEF when needed since we don’t drive as much in the last few years (avg 2,000 miles per year) so it is always fresh.
- or keep it full so it does create any crystallization (or whatever it may do). But then the DEF will get old…especially in the heat.

I figure a happy medium would be to fill it at the beginning (or end) of the season and then drain it at the end of the season (or one year mark) and refill. This way, it would be fresh and full (at least most of the time). But I would probably end up dumping 5 or 6 gallons of DEF each year. Seems like a waste of money…

Thoughts?

As far as the Box vs Pump debate, although I have used pumps a few years ago, I have not since 1999, mostly due to the lack of long distance travels.

 

[Rich W.]

Great thread…. I read with interest since as I also debate whether to:
- only fill DEF when needed since we don’t drive as much in the last few years (avg 2,000 miles per year) so it is always fresh.
- or keep it full so it does create any crystallization (or whatever it may do). But then the DEF will get old…especially in the heat.

I figure a happy medium would be to fill it at the beginning (or end) of the season and then drain it at the end of the season (or one year mark) and refill. This way, it would be fresh and full (at least most of the time). But I would probably end up dumping 5 or 6 gallons of DEF each year. Seems like a waste of money…

Thoughts?

As far as the Box vs Pump debate, although I have used pumps a few years ago, I have not since 1999, mostly due to the lack of long distance travels.

An option is to drain the tank and fill it with distilled water for storage, then dump that and fill with fresh DEF for travel. Just dont forget and drive off with a tank full of water or you’ll quickly start throwing codes and be on the road to derate.

 

[Richpatty]

An option is to drain the tank and fill it with distilled water for storage, then dump that and fill with fresh DEF for travel. Just dont forget and drive off with a tank full of water or you’ll quickly start throwing codes and be on the road to derate.

Interesting thought...although since we store it a home, we do take it for a 50 mile drive every 30 days to give it a run and also run the generator, heat and other items so they stay exercised....so filling it with water would work for us.

Thanks!

 

[DavidL]

An option is to drain the tank and fill it with distilled water for storage, then dump that and fill with fresh DEF for travel. Just dont forget and drive off with a tank full of water or you’ll quickly start throwing codes and be on the road to derate.

And I assume that is for non freezing weather storage?

 

[Rich W.]

And I assume that is for non freezing weather storage?

yeah - storing in sub freezing temps isn't part of my reality so those ramifications don’t occur to me. I’ve never even winterized an RV. You wouldn't want a block of ice in your DEF tank and DEF doesn't start to freeze until 12°F so DEF would be better in the tank for low temp storage. And DEF wont go bad at low temps either, so the distilled water thing would only apply to areas where temps would be higher. And in those areas people probably don’t store there rigs anyway so on reflection this probably wasn’t a very useful suggestion. Time for cup of coffee…..