Community Forums

Mattdenryter · 01-07-2021, 04:43 PM

Hi everyone,
I just recently purchased my first diesel motorhome a couple weeks ago. It’s a 2012 fleetwood discovery 40g Cummins 8.3 L
I’ve done some reading on DEF, from what I’ve read it’s best to get from truck stops because it’s the freshest and highest turnover compared to store bought.
True or False?
And to follow up on that the few truck stops I’ve stopped at like pilot, flying J’s etc, only have the DEF on the driver side pump. My DEF tank is on the passenger side. Is there any reason I couldn’t fill DEF into a specific portable container then fill the DEF tank in the MH.

Thanks in advance
Matt

iowaone · 01-07-2021, 04:48 PM

Just buy it from Walmart. No one has had trouble with it if the container has not been broken. Too much risk of contamination by messing around with filling and emptying containers.

fagnaml · 01-07-2021, 05:21 PM

Matt --

Congrats on the purchase of your first ever motorhome!

I concur with iowone -- purchase Walmart brand of DEF (about 2/3 the price of the Peak brand Blue DEF for the same stuff -- urea). Then if you want to save a few more pennies, keep the empty DEF container and refill it from a DEF pump at a truck stop.

My motorhome is designed with the diesel fuel nozzle behind the driver side left (and passenger side) front wheel and the DEF tank behind the driver side rear wheel. To use a DEF pump at a truck stop means after filling the diesel tank I'd have to move the coach forward to then fill the DEF tank. Using a 2.5 gallon jug of DEF is much more convenient for me.

Best wishes for safe, healthy, enjoyable travels in your new vacation home on wheels!

Dutch Star Don · 01-07-2021, 05:36 PM

X3 on buying Walmart DEF. You won't go through it fast enough to worry about filling at the pump, just put a jug or two in when you're home from a trip.

There have been a LOT of DEF head issues. It hasn't been proven, but some of the suggestions have been to NOT buy at the pump (nasty crusty and dirty) and to not overfill, as it can get up in the DEF head components. Again, not proven information, but worth following until they get this DEF head issue resolved.

The overfilling is more critical on coaches with DEF fills on both sides. The side away from the tank uses a long cross coach hose. When you top off, that hose stays full and can cause issues with the DEF head.

FC901 · 01-07-2021, 06:03 PM

Matt---- As others have said, Walmart is the best answer for buying DEF.

The price at Walmart near me is only $6.99 for the 2.5 gal. container. Down a few months ago from $7.49.

Enjoy your Discovery, great coach!

Check out the Discovery Owners Group site. Very Knowledgeable members are always willing to answer questions about... most anything coach related.

Travel Safe.

alank · 01-07-2021, 06:03 PM

I only use BlueSky DEFF, the stuff that truck stops & other places sell at twice the price. Shop around, I get mine at a farm supply store, regular DEFF price, and comes in a sealed box of 2 - 2 1/2 gal containers. Since it's usually higher priced, it makes me think it's better, but in reality, I have no idea if it's any different or not.

txcpl · 01-08-2021, 05:00 AM

DEF is DEF, no matter what brand. I use the DEF from Atwoods whenever I find it. Theirs is the best price I have found. I keep a jug onboard and will fill up whenever it gets to 1/2 tank. One thing about DEF is to keep it fresh in the DEF tank.

Crasher · 01-08-2021, 08:50 AM

My DEF tank is also on the passenger side. I'll carry a jug with me for emergency, but with a 13 gallon tank using a gallon every 400 miles, we have a 5,000 mile range full to empty. When traveling, if I get fuel at a truck stop that is not too busy, I'll turn around and come back through the island and fill with DEF. I empty my jug and refill so it is fresh again. @ 10,000 miles per year, I only need three fillups to have plenty of reserve. Truck stop pump DEF or DEF in a box from any supplier all works the same. Pick the method that works for you.

purrin along · 01-08-2021, 09:21 AM

Quote:

Originally Posted by Crasher

My DEF tank is also on the passenger side. I'll carry a jug with me for emergency, but with a 13 gallon tank using a gallon every 400 miles, we have a 5,000 mile range full to empty. When traveling, if I get fuel at a truck stop that is not too busy, I'll turn around and come back through the island and fill with DEF. I empty my jug and refill so it is fresh again. @ 10,000 miles per year, I only need three fillups to have plenty of reserve. Truck stop pump DEF or DEF in a box from any supplier all works the same. Pick the method that works for you.

This is good info I can use,thanks.

Cincy Steve · 01-08-2021, 09:30 AM

The most prevalent concern is for the shelf life of the DEF. Most of what I've read says it's good for a solid 12 months, longer yet in a cool climate. However, if you don't run a bunch of miles annually, (I know people who barely run 2000 miles/year) are you running on diminished fluid by the time you get to the bottom of the tank?

I wait for our tank to drop to 1/2, then fill my own container @ a truckstop, dumping it in later, @ a convenient stop.

My "theory" is that I'm diluting the "old" stuff w/new & so improving the overall quality of the material in the tank.

BillJinOR · 01-08-2021, 09:46 AM

Not having def to deal with myself , My question would be why are all you low mile (<5000 miles a year) filling the def tank? Or Topping it off when it gets to half ... Wouldn't it make sense to run with 1/2 tank or even less assuming its 10 or more gallons and I guess you can get 400 miles on a gallon? That way the stuff is always fresh, which seems to be a concern issue. Keep a sealed emergency jug onboard just in case but otherwise.... Truck stop pump def is great if your running 1000 miles a week like the average trucker, but your not , so I would think the 2.5 gal jugs would be perfect, and better sealed until opened. Am I wrong?

530ktm · 01-08-2021, 10:05 AM

I usually let the tank get between empty and half then I put in a jug from Walmart and bring it up to 3/4. I never top it off and I do carry a spare jug or two on board at all times. Always buy the Walmart brand and never get DEF at the pumps.

Mr Ted · 01-08-2021, 10:15 AM

Stopping at large truck stops and buying Def at the pump is your best bet . Always fresh and never have to mess with those containers. Of course its fresh. Truckers put on Millions of miles from it. Do you think they would risk those rigs? Or put up with poor quality ? Do you think they stop at Wallmart ? Would you buy Diesel in cans and dump it into your coach ? Of course not.. Save Time and Money and be assured quality products.

Mr Ted · 01-08-2021, 10:19 AM

Quote:

Originally Posted by BillJinOR

Not having def to deal with myself , My question would be why are all you low mile (<5000 miles a year) filling the def tank? Or Topping it off when it gets to half ... Wouldn't it make sense to run with 1/2 tank or even less assuming its 10 or more gallons and I guess you can get 400 miles on a gallon? That way the stuff is always fresh, which seems to be a concern issue. Keep a sealed emergency jug onboard just in case but otherwise.... Truck stop pump def is great if your running 1000 miles a week like the average trucker, but your not , so I would think the 2.5 gal jugs would be perfect, and better sealed until opened. Am I wrong?

Why would you carry around something that is sold at Every fuel stop in the nation? Would you carry Extra Diesel ? Maybe some would :( Waste of space and weight to do so.