New to diesel fuel

I've beem driving various GM and Ford diesels since 2005. I never put anything in the tank but diesel. These vehicles were all driven regularly so tje fuel was always new.
DEF will eventually expire. I would fill your tank if it's going to sit for months.

KD4UPL wrote:
I've beem driving various GM and Ford diesels since 2005. I never put anything in the tank but diesel. These vehicles were all driven regularly so tje fuel was always new.
DEF will eventually expire. I would fill your tank if it's going to sit for months.

wouldn’t it be better to not fill the tank so you can put fresh stuff in when your ready to go again?

Been driving diesel equipment for 24 years. We have many diesel storage tanks in storage bins that sit between jobs or phases sometimes for months. The tanks are not what I would call sealed or air tight and the fuel is fine. I would only use additives if you are parking where it can freeze.

I would also keep the DEF tank full when sitting. Some of our issues with DEF have been from crystals forming which I believe are from the tank drying over time because it is not full.

I have a older MB diesel ,I don,t put anything in the fuel 2007 no problem. in ohio stored in oct garage kept. I do take it for a 20 mile drive on dry nice days when the salt has been washed off the roads. about three times a winter.change oil,filter, an fuel filter, keep tank full keeps condensation out.hate def won,t buy a diesel that uses it.

ronharmless wrote:

KD4UPL wrote:
I've beem driving various GM and Ford diesels since 2005. I never put anything in the tank but diesel. These vehicles were all driven regularly so tje fuel was always new.
DEF will eventually expire. I would fill your tank if it's going to sit for months.

wouldn’t it be better to not fill the tank so you can put fresh stuff in when your ready to go again?

Diesel does not have the same characteristic as gasoline, particularly ethanol based gas which attracts water. It stays "fresh" for just about forever in a sealed container. You want to fill the fuel tank though as an air space helps to encourage the growth of bacteria and funguses which can play havoc with your fuel system. I use an additive which also discourages that from happening but it's not an issue if you are going though fuel every week.

All good responses so far. I’ll try to add to that.
First nothing special you need to do with the fuel for storing the vehicle for Id say, a year or less. As said, diesel is much more forgiving than gasoline. If storing long term I’d consider adding a biocide as a preventative measure.
No other additives needed or even preferred (ulsd lubricity or lack thereof is a non issue in newer engines). Except if you’re running fuel in cold weather that has not been treated to prevent gelling.
But even this is not an issue unless running summer fuel in below freezing temps, or changing geographical location from somewhere that doesn’t treat for winter and driving into cold weather. (Example fueling up in Vegas in the winter and then driving N into Utah). But anywhere it gets cold, the fuel is already treated before it goes in the storage tank. In those cases, unless it gets much colder than the average lows for the area, also no concern. (I’ve only seen this happen once, large scale. Denver dropped to -30F one morning and all the local fuel was not treated for that extreme. Most local diesels gelled up for a couple days)

Storage, I always leave tanks as empty as possible. Gas or diesel. With gas, any minor condensation that may happen in the tank gets adsorbed with a good ole fashioned fillip of E10 gas. But suit yourself here. The jury is out on this one.
DEF. Do a little research but bottom line, it’s best to store vehicle LOW on DEF. So you can add fresh when you drive it. You can research shelf life and what affects that negatively (heat mostly). But if it’s cold out the def will freeze and not degrade further. It freezes at 12degF I think. Best bet is do what you can to keep any def in the tank less than a year old.
Or minimize the old stuff. Not too difficult under normal circumstances. Once you get a feel for how much it uses, you can plan to run it low before layup.
Another myth is what def is better for your vehicle. This is purely a myth. Unless it’s old or boxed def was opened, the quality of box def or pump def is both just fine.

Congratulations on the new rig. It’s not too bad “dealing” with diesel. Less concerns than gasoline imo. Just keep your eye on maintaining the quality/age of the def.

midnightsadie wrote:
I have a older MB diesel ,I don,t put anything in the fuel 2007 no problem. in ohio stored in oct garage kept. I do take it for a 20 mile drive on dry nice days when the salt has been washed off the roads. about three times a winter.change oil,filter, an fuel filter, keep tank full keeps condensation out.hate def won,t buy a diesel that uses it.

Yet the more advanced tier IV emissions systems that were introduced to on road vehicles just a few years after your 07 with DEF are more fuel efficient and more reliable from a DPf/EGR/soot control standpoint. (Unless your 07 is actually a late 06 production and is only Tier III in which case I agree and you have a gem. Hence why mid 2000s diesels generally bring a premium over late 2000s diesels).

I am with you though. My strong preference is to not have to deal with tier iv emissions on my personal vehicles. But I know that time is coming. Been driving diesels since they started out-pulling gassers in pickups. The old Detroit 6.2/6.5 and the cornbinder 6.9/7.3 IDI diesels were like the 70s/80s emissions and the first few years of EVs. The diesels were not advantageous compared to a good ole fashioned gasoline engine. Except the fuel mileage was commensurate with the lack of performance! Lol.

Picked up a 2016 a couple years ago, semi reluctantly, but couldn’t pass it up and it was already deleted. It’s really nice having a newer truck that runs just like an old 06/07 model with ZERO emissions issues or concerns.
That said, if I bought a new diesel truck tomorrow I’d give it a fair shake running factory emissions. But I’d be very tempted to snatch up a delete programmer while I still can, to put on the shelf, just in case.

It depends on the weather and how long your vehicle sits. Fuel stabilizer is a good idea in the off season. Diesel can grow algae in it. Hot humid climates are bad for algae formation. diesel additives will take out moisture which accumulates in the tank from condensation.


DEF has a shelf life of 6 months to a year depending on who you talk to. Add DEF when are ready to use your rig.

Todays diesel fuel has less sulphur. Sulphur added lubricity to the fuel systems and parts. I use opti- lube XPD additive to my fuel every fill up. My engine does not require DEF. It's an 06Duramax with 100K miles. The cost to replace the injectors on my engine is 3K. The additive, in my opinion holds that off a bit longer. A 60 dollar gallon lasts me a year. 3 oz per fill up.
Keep your fuel filter on a regular schedule. Diesel contains a bit of water. I purchase from stations that have a good turn over. Now the diesel is a renewable blend. i find my mileage has decreased since the switch over.

From the California resources board :R " Based on experience from other countries, equipment manufacturers and consumers have expressed concern regarding the lubricity of California diesel fuel as sulfur levels are further lowered. Unfortunately there is no currently accepted standard used for lubricity by the industry, therefore a lubricity standard has been included in the ARB’s proposal. "
So basically they don't know yet they say they included a standard. So what is the standard. :h

You don't need to add special lubricants to diesel. ULSD has been around for a long time and your 2023 motor is designed to accomodate it.

Crud growing comes from getting water in the tank and letting it sit. The stuff grows at the interface between the water and diesel. If you burn off the fuel regularly and get fuel from reliable high turn over stations, it's unlikely to be an issue. If it's going to sit for months, it won't be a bad idea to put some of the diesel biocide in the tank though this is much more an issue with boats where many tank systems are poorly sealed.

Do keep a spare water separating fuel filter and learn how to drain/change it out.