Community Forums

Mr. T · 10-12-2019, 07:20 AM

I've been reading up on the importance of using DEF that's well within it's shelf life. I plan on spending 6 months at a resort in Arizona. Do I need to be concerned with the quality of my DEF after sitting for so long?
Thanks!

NH Dave · 10-12-2019, 07:42 AM

Quote:

Originally Posted by In2flyfishin

I've been reading up on the importance of using DEF that's well within it's shelf life. I plan on spending 6 months at a resort in Arizona. Do I need to be concerned with the quality of my DEF after sitting for so long?
Thanks!

I've heard the same. Yet, store our coach typically from now through April every year for the winter months as many other people do as well...so I've never really concerned myself with that too much.

I'm not sure when or under what circumstance that applies...? Maybe it's a 'legal thing' for proactive claim mitigation? These diesel engines are quite expensive to work on and maybe that helps them with being on the 'blame list'. Or maybe, protection from vendors who might be trying to sell old inventory 1 or 2 years old? Who knows...?

Good question though!

FLJOE · 10-12-2019, 07:51 AM

This is how I handle my "winter down time" as far as the DEF is concerned. We will be stationary in SW Florida for either 4 or 5 months. I make sure the last DEF I add will be from a Pilot or Flying J bulk tank. My thinking is that it is probably fresh.

I will only sit with about 1/2 of a full DEF tank and then just prior to heading out in the spring I will top it off with fresh.

I honestly think you could fill your tank with fresh DEF and let it sit for 6 or 7 months and you would be fine though.

MuggsnMe · 10-12-2019, 08:37 AM

The place where I work we have a 250 gallon bulk tank of Def. When it gets down to approx 110-120 gallons I call to have it refilled (approx every 2 months). Been doing this method since 2012 & have not had any problems. I agree with FLJOE that if you only fill it have way for your winter months then top it off before you head out you will be fine.
Thanks
Bob

grindstone01 · 10-12-2019, 08:52 AM

I believe that DEF is good for up to 2 years in a vehicle (do the research). I also would store the vehicle DEF tank on the low side and fill w/fresh DEF when needed.

TJ · 10-12-2019, 09:00 AM

From what I've read, you are better off keeping your DEF tank full when your coach is sitting idle for a long period. That reduces the possibility of crystallization inside the tank.

Be sure to start the coach and let it run for a few minutes every couple of weeks. That allows the DEF heater in the tank to cycle.

This has worked for us over the past six years.

TJ

FLJOE · 10-13-2019, 09:40 AM

Quote:

Originally Posted by Tranquil Jim

From what I've read, you are better off keeping your DEF tank full when your coach is sitting idle for a long period. That reduces the possibility of crystallization inside the tank.

Be sure to start the coach and let it run for a few minutes every couple of weeks. That allows the DEF heater in the tank to cycle.

This has worked for us over the past six years.

TJ

I used to worry about crystallization but I think it was someone on here claimed that once fresh DEF is added any crystals dissolve.

I refill the same DEF container at diesel truck lanes when I fuel so I don't have to move the coach around and take up valuable time when others are waiting. I then add the DEF later while in a campground.

My DEF container has small crystals that form of course, just like an almost empty DEF tank would. I used a funnel with a fine screen the first couple times when I poured DEF out of this container just to see if there were any crystals floating around. Nothing was in there but regular clear DEF.

So my point to this long winded post is that IMHO if you leave your DEF tank almost empty it may form small crystals. However if you fill it or even move it down the road those will dissolve immediately when introduced to liquid DEF.

Dutch Star Don · 10-13-2019, 09:48 AM

I think the biggest thing to remember.....DEF is been around 8-9 years or so and there haven't been a bunch of issues with DEF as related to age. You hear about sensors that quit or other mechanical things, but not about old DEF causing issues. There have been 7-8 years of people winterizing their coaches without issue.

I just don't think it's an issue to fret about. Now if you find a six year old box in someone's shed in Arizona, you may want to toss that one.

Renipladlo · 10-13-2019, 04:39 PM

Several good videos on YouTube on DEF. We just got back from Nappanee, IN, about 1300 miles RT. DEF tank was full when we left, added 2.5 gallons upon arrival in IN. Got home added 5.5 gallons to get it full. I keep it full when storing for any length of time, to keep condensation from forming. DEF has shelf life based on temperature the hotter it is the less time it will last, Cummings and Freightliner has information on it, suggest all read it at their leisure. Carry extra for trips we have coming along. It's cooling off, so it won't be problem keeping few gallons around over winter. On this site, suggest all read some of the problems others have experienced with DEF and the systems installed to make it work correctly, you might have eyes opened. Cannot pin down with any accuracy how much is used for XX amount of travel, no past trips have a method of calculating to any degree of accuracy for me. Never let tank go below half empty before I add DEF to it, don't want to even get close to limp mode. Gallon for gallon DEF may be much more expensive than diesel, except in CA. I don't use the "pump" for my DEF, and have used Walmart's brand without problems, mixing the blue in for good measure about 50/50.

FLJOE · 10-13-2019, 06:37 PM

I used to purchase my DEF at Walmarts. I always checked to make sure the seal was unbroken and not tampered with prior to lugging it to the checkout. The issue I had was several times I found the seals off when I removed the caps. It was impossible to tell if someone had filled it with water and returned it or if the seal had just failed. I wasn't willing to take the risk.

It takes me an extra couple of minutes to fill my DEF container at the truck pumps and put it back inside my storage bay. I always get it cheaper than buying at Walmart, I don't have to lug it from Walmart to my RV, and I know it is pure fresh DEF that has not been compromised.

TJ · 10-13-2019, 07:06 PM

Quote:

Originally Posted by FLJOE

I used to purchase my DEF at Walmarts. I always checked to make sure the seal was unbroken and not tampered with prior to lugging it to the checkout. The issue I had was several times I found the seals off when I removed the caps. It was impossible to tell if someone had filled it with water and returned it or if the seal had just failed. I wasn't willing to take the risk.

It takes me an extra couple of minutes to fill my DEF container at the truck pumps and put it back inside my storage bay. I always get it cheaper than buying at Walmart, I don't have to lug it from Walmart to my RV, and I know it is pure fresh DEF that has not been compromised.

If you fill your DEF container at truck stops, why don't you just fill the DEF tank directly? Just curious.

We get about 700 miles per quarter tank of DEF (one green bar) and refill every other fuel stop.

TJ

grindstone01 · 10-13-2019, 07:19 PM

When my Chevy DEF light comes on, I have a 100 towing miles to find a truck stop for a DEF fuel up. So far it's not been a problem.
The only time I use a truck stop is for DEF only. There always seems to be one within 100 miles.

Dutch Star Don · 10-13-2019, 07:27 PM

I've only found three fuel stops with DEF at the pump in 6 years of owning a DP requiring DEF. The main reason....I don't use truck stops to fuel. Consequently, I buy the majority of my DEF at Walmart and fill the tank at my leisure, at home.

I bought the $25.00 refractometer from Amazon and check the DEF when I think a seal has been broken. It takes about two minutes to check the DEF.

Renipladlo · 10-13-2019, 08:16 PM

Like all I check the seal on the Walmart brand every time.

TJ-Never thought to fill my Jug at truck stops, good idea, assuming the hose neck is small diameter like gas nozzle.

DSD, have not purchased refractometer yet, but thank you for the reminder, it was in wish list, and now it's gone. Going to put it back and order it too. Most every Pilot/Flying J at the truck island has DEF. Going to try my TSD card at loves, but don't remember seeing them their either.

FWIW - I use my wish list like a post it note pad, keeping in things I have already bought, but might buy again, or need to tell someone about that little thing.