Tech talk #8 Part 2/2: Everything you need to know about DEF fluid

[@bkdexter79]

As a new diesel owner, I would never have had any idea how important this information is. Thank you for explaining this in simple terms.

[@chtomlin]

really excellent presentation!

[@CW-qt1qv]

Excellent video. Thank you. I've had a DEF truck for eight years and always followed these procedures. Always! Never had a problem other than one time I let DEF get low because I was coming up on the summer months - A warning came on! The one time I didn't (filled the DEF tank from a fuel station) apparently my DEF pump goes bad and needed replacement. Guys, this is good information!

[@InGLORyisBSTRD]

Just bought a new 2019 F350 Superduty with a 6.7 Powestroke- This video is by far the best I've seen- especially for a newbie like me to the diesel world. Now I am armed with the knowledge of manufacture dates and where to buy- before I buy my first gallon of DEF. You sir, may have saved me allot of money by helping me avoid a costly mistake!

[@rsg1963]

Walmart DEF FTW, it flies off the shelf, no date issues! And it's several dollars less per gallon.

[@MotorCityMechanic]

Works for me. Thanks for the input and make sure to subscribe.

[@jeffl4823]

Hey there... thanks for a great video. A long time ago I was an ASE Master technician. Stopped working on cars for a greater passion in my life... joined the Military to defend our great nation. I want to thank you for a fantastic video. Helped me understand DEF better. I'm currently going through a DEF repair at the dealership. Thank the gods it's not like several I have heard about and it is covered under warranty. I will buy the proper detectors and test my DEF from now on before using it.

[@MotorCityMechanic]

Thanks Jeff for watching. The main thing is make sure to use only new/fresh...nothing questionable and you should be okay. Thanks again and make sure to subscribe and check out my other videos.

[@gowanfenley]

Extremely useful, and surprisingly rare information on DEF. Another great video, Dave.

[@MotorCityMechanic]

Thanks Gowan. Always happy to share some knowledge. Thanks for checking it out.

[@ednieves3973]

Thanks David, very informative. When I take long trips pulling my car trailer, I purchase a fresh bottle of Mopar DEF fluid and take it with me. Now I know not to leave it in an area that is hot.

[@MotorCityMechanic]

Thanks Ed for watching both parts. Glad you found it informative.

[@renepraisehim]

You could also just do the math backwards. Take the current year... say it is 2019... and subtract 1, giving 18. The 3rd and 4th digits on the Peak bottle should be at least 18, meaning it is at most one year old. If 17, you may want to pick another bottle or calculate the Julian date as you describe. So in 2020, I will just look to make sure those first numeric digits in positions 3 and 4 are 19 or higher. Thanks for an informative video, you now have a new subscriber.

[@MotorCityMechanic]

Sorry for the delay Tom.....thanks for that method as well and for subscribing!

[@vladsamolya7658]

Great video. Thank you so much! Also main reason why I googled this was cause I wanted to know the affection on health keeping some def in the cab of truck drivers

[@joejohnson3441]

Great video! Thanks! You now have to make a video on the theory and operation of DEF and the SCR system and its components and what happens when you have bad or diluted DEF in your system including the possible repairs needed and also the costs involved. Most diesel truck owners are clueless and really need to know this stuff before they make a very costly mistake.

[@MotorCityMechanic]

Thanks Joe. I will certainly keep that video request in mind as a future video. Make sure to subscribe

[@claytonopinionbartlett8930]

Yea, like buying a diesel truck. I fixed my d,e,s, it was a bitch ! But I saved around 1200$ .or more if I took it to the stealership.

[@boomerantics9586]

Very informative -thank you! I’m driving a 19 year old truck and recently ordered a new one and had never heard of this DEF stuff (thanks government!). In studying the manual before the truck arrives I find you have to be careful about filling the tank in winter or it may freeze and damage the tank, the vehicle will be disabled and then immobilized if you run low or run out, or an improper mixture is detected, etc, etc. Swell! But again, thank you for a very helpful video!

[@MotorCityMechanic]

Boring Baby Boomer Goes Your welcome. For the most part most people don’t have issues. Typically I find more issues with the sensors or the def pump and not anything fluid related. Thanks for find the channel and make sure to subscribe

[@kaivonmortazavi8656]

Great Video. I was aware of DEF shelf life issues impacted by age and storage temp. Conditions but was not aware of methodology on interpreting the codes to come up with mfg. date for blue DEF. Can this methodology be extrapolated to all other makers who use codes instead of clearly marked dates? Its interesting that our govt. can impose requirements for “Use by….” or “Best by….” Or “Sell by…..” dates for food products but does not have the balls to make the makers of DEF fluids have clear, easy to read “made on” or “Use by” or both dates on this products and leaves the burden on the consumer. Clearly their pockets are greased by the petrochemical industry and the interest of the consumer is secondary. My hat off to the makers that print easy to understand “made on” and “Use by” dates.

[@michellefriend8848]

Excellent coverage. Thank you.

[@luismaceira8850]

Great and awesome job... I just had an issue with our 2019 Doge diesel. It cost me $270.00 to flush out the whole system. I truly will keep and eye on the date and year when the DEF was made... Thank you. Luis

[@MotorCityMechanic]

Your welcome and thanks for watching the video. Make sure to subscribe Luis.

[@TheManKnownAsJR]

1- A good idea is to buy from a truck stop because their inventory is usually active and cans don't sit around for too long. 2- Best used by is like like a best before date on food. In optimum conditions, it can last for a while. 3- Got a 1 gallon bottle in the garage, which is about 4yrs old but been opened; will throw it away. 4- Pump DEF is good for commercial trucks because they don't remain in the tank for too long; and is a good deal. 5- Stocking about 5gal. which fills my truck up once; good for thousands of miles. 6- Keep DEF cool and out of sunlight, is what the dealer told me. 7- Apparently, it can be frozen to keep longer but can't substantiate that claim; DEF does freeze in winter.

[@cjcooper4370]

Awesome man. Some DEF troubleshooting video series would be awesome.

[@MotorCityMechanic]

Many thanks. I will certainly keep it in mind as a future video series. Make sure to subscribe if you havent already.

[@bob4465]

Thank you for your very instructional video. I'll probably switch to MOPAR. The local Ram truck dealer is where I get my MBZ Sprinter serviced anyway. Remember, Mercedes used to own Chrysler so their dealers are very familiar with the model and have all the special tools and manuals. Manufacture training, too.

[@MotorCityMechanic]

Good idea for sure Bob. Over the years some of the diag equipment had gotten broken or missing and most dealers wont order new stuff because they dont see enought to justify it. I can say for sure thats how our dealership is. Those who did work on them have long since moved on and some of the tools have gone missing. Its the joy of working on older vehicles and the cost that is required to keep all the items you need with the hope that you will work on enough of them to justify the expense. Most of ours end up at Mercedes for those reasons. Thanks for watching and for the comment. Make sure to subscribe.

[@scottfhscottfh]

I buy a 1 gallon jug only at a time. I only fill my tank to half to 3/4, depending on if its winter or summer. Lower fill level in winter,. I fill the full 1 gallon jug and do not store opened containers.

[@edmor1086]

What a fantastic job you did on this video.

[@rgdowntheroad]

You are the best with the information you provided in this video. We have a diesel also and have had to put up with many def issues. The sensors have gone bad, the def tank would not read correctly and as you said it can be costly. The Julian calendar issue is BS. I thought it was a joke when someone told me. Thanks for making people aware Wonderful videos. Thanks. Kathy and Rich

[@outlaw6849]

Awesome! I just purchased a silverado 3500 6.6! You explained DEF in a way anyone could understand! Thanks

[@MotorCityMechanic]

Glad I could help. Keep good clean DEF much like you would diesel fuel and you will be doing your part and not causing possible issues. Thanks for watching and feel free to subscribe

[@TierOneLandscapes]

Nice job on this video.

[@alangwin3891]

Man oh man! I am very happy to have stumbled onto your channel. Thanks so much! Wish you every success.

[@MotorCityMechanic]

Thanks for landing on my channel. I appreciate the visit and for the comment. Make sure to subscribe Alan.

[@pbr549]

Great video. I was not aware that there was an expiration date on DEF fluid. 2 years.

[@MotorCityMechanic]

Many thanks! Sure is.....they just assume it wont be on the shelves long enough to make a difference I suppose. Make sure to subscribe,

[@clarenced.950]

That was super informative I hope you get a ton of views. But I do have one question is it riskier to keep the DEF tank full, constantly topping it up or run the tank lower adding fresh DEF just as necessary.

[@MotorCityMechanic]

If you can keep it lower then its best. If you drive alot then keeping some on hand and adding when needed is best as well. Thanks for asking and watching. Make sure to subscribe.

[@pumkinhead6636]

Both parts, very informative. Thank you. I tipped your jar.

[@MotorCityMechanic]

Much appreciated! Make sure to subscribe

[@wyattoneable]

The military uses "julian" dates so I'm familiure. Thanks for the information, it helps a lot.

[@MotorCityMechanic]

It's the reverse Julian date that I don't understand......why? Lol. Thanks for the comment

[@cavtj1]

Hey Peak, why not put the friggin date on the bottle and take the confusion out of it (like Mopar)? Maybe I am over thinking this, but it seems like you don't care if the customer is stuck with bad DEF, you got your money.

[@MotorCityMechanic]

I agree that it should be simple.....no need in doing rocket science to figure it out. Thanks for watching and dont forget to subscribe if you havent already.

[@stevewithavision]

great information to know, Thank you for posting this video. Great job. Is there a way to empty the DEF tank to get old fluid out?

[@jrlonestar]

THX BRO...GREAT VIDEO, NICE VIDEO!!!, GOD BLESS, STAY SAFE, JOE!!!

[@davidkovalski1531]

Man, I'm glad I have an 05 LLY!

[@MotorCityMechanic]

Glad mine is a 2007 as well lol. Thanks for watching and for the comments. Make sure to subscribe

[@trekcity9491]

I personally DON'T agree with what he said about NOT buying DEF from a truck stop, I'm a commercial 18 wheeler with a DEF system and we go through so much DEF at the big truck stops (Pilot, Flying J, Loves, TA) that they always have fresh DEF on a weekly basis if not daily basis

[@meadowviewlawncarellc8079]

Nice. Learned some new things thanks Dave. Luckily I don't need def, it's really a shame and a pain what you gotta do theses days. Thanks epa!!!

[@MotorCityMechanic]

It can be an added pain for sure. I too am glad that I don't have the system on my diesel.

[@carmelitaenano4423]

Thank you for sharing this information.

[@MotorCityMechanic]

Your welcome and thanks for watching!

[@om603denis]

Bro! You're the man! Thanks for the info!

[@MotorCityMechanic]

Many thanks and appreciate the comment

[@SuperDaveAgain]

Well done.

[@arthurrodesiler3109]

What a pain. I never buy a diesel for this reason. You have to know how long its been in the tank of the truck I would think. If you don't use a lot it can go bad I guess faster if its hot outside. I see to many problems with this mess.

[@northerngunner2756]

I’m so glad I don’t have to deal with this .

[@johnniecameron8829]

WHO NEW ,THIS IS GREAT INFO

[@MotorCityMechanic]

Appreciate it Johnnie! Thanks for watching....make sure to subscribe

[@darbyclay6928]

Thanks for two very informative videos. Great job. I needed the tips and advice!!! Well done.

[@oldgoat8861]

Thank you...you taught me alot!!

[@MotorCityMechanic]

Your welcome Mark......thanks for watching both parts. Make sure to subscribe and check out my other videos.

[@bobabooie6389]

Thank you 👍🇺🇲

[@pumkinhead6636]

Thanks!

[@deant876]

I know that you are from the south, but you did not show the effects of cold on the DEF.

[@hammer-r]

Thank you. Good info.

[@MotorCityMechanic]

Your welcome

[@dashcam5398]

I have a fridge in my garage and that is were I store my jugs of def., constant cool temperature

[@willrobinson7468]

Good information.... thanks....

[@MotorCityMechanic]

Your welcome and thanks for the feedback Will

[@formerice]

Bought a 17 Ram EcoDiesel. Now I'll buy my DEF at Walmart. Definitely have a fast turnover. Rotella T6 there too. Great video! Loving my Ram!

[@wysetech2000]

Very informative video's. I learned a lot from them, thanks. The fluid must go bad in the tank on the truck before it's all consumed.

[@MotorCityMechanic]

When researching....there is never any mention of the life of the fluid in the tank of the truck. That makes me think that its treated the same way as the def in the bottle. So its possible that it can break down overtime as well.

[@otterman52]

Well done. Very informative.

[@MotorCityMechanic]

Many thanks! Make sure to subscribe and check out my other videos as well. You might just find some more that help.

[@oldsalt8011]

Outstanding Video!

[@rongrant6453]

Super video - great info. Thank you.

[@MotorCityMechanic]

Glad to be able to share the info. Thanks for watching and make sure to subscribe

[@BonheurEsperer]

Very helpful. I cannot use my truck now because i have problems with the DEF.

[@MotorCityMechanic]

Yeah that’s a big issue when the system fails and it can get very costly as well depending on the cause.

[@rosyoung806]

Very informative video, Thanks for doing it!

[@MotorCityMechanic]

Your welcome and thanks for watching. Make sure to subscribe

[@garvdarb]

And all it really does is add moisture to the exhaust and the exhaust falls to the ground as the particuate is heavier than air.

[@backcountryadvmoto]

Great video man! Broke it down scientist style. Lol! Thanks

[@MotorCityMechanic]

+Backcountry Adventure Motorsports Thanks man! Thought it was something that needed to be dealt with and explained more about. Make sure to subscribe!

[@backcountryadvmoto]

MotorCity Mechanic I subscribed a while back. Love the videos. Also commented on another video about the water pump replacement. I have a 2016 3500 HD MEGA CAB DRW that is haven't some cooling issues when towing heavy in long grades. I've explained it a little more in detail in the comment. Please take a look if you get a chance

[@rxbristol]

Beautifully done...thank you.

[@MotorCityMechanic]

Your welcome Rex. Many thanks to you

[@dougdrefus3554]

So why does Peak encrypt the expiration date? Most people will not be able to read that code. I do not carry my Julian calendar with me every day. Sounds like Peak wants the buyer not to know its expired and not good anymore.

[@MotorCityMechanic]

doug drefus I have to wonder as well. They are the biggest name in the DEF market which means they have the most shelf space. So of course there will be some old stock out there. I'm sure it sits there until it gets sold. Then the consumer doesn't know it's already expired. This can only mean one of two things.....either the industry is being overly cautious about the fluid going bad and and then it doesn't matter or the bigger company is hoping the average person doesn't know and buys what ever is sitting on the shelf. Personally I would try to find fluid that has the dates clearly marked. Thanks for watching and make sure to subscribe

[@scottleggejr]

The answer is simple. $ale$

[@philiphandley6563]

No Julian calendar needed for a close enough guesstimate. -150 days from Jan 1st... ~30days/month... 150/30 = ~5 months. Jan 1st - ~5months = ~ August 1st. easy peasy.

[@edmorse3529]

Excellent video!!!

[@bobbybeste1931]

This is from Ford dated March/2018 VEHICLES CONTAINING DEF DEF in a vehicle is still acceptable for vehicle consumption even if the vehicle has been exposed to temperatures above 86 o F (30o C). For the same reasons stated above, at these temperatures, urea concentration will remain reasonably stable. • DEF in vehicles is susceptible to the same degradation as in containers. • The SCR (selective catalytic reduction) system has been calibrated to function properly with urea concentrations different than 32%. The only consequence of operating with a urea concentration less than 32% is faster consumption. • DEF that has degraded beyond the point for the calibration to compensate will set off a warning on the instrument panel (refer to the owner guide). • Unless there is a warning light on the instrument panel there is no reason to consider draining the DEF from the tank simply due to age of the DEF. However, it is highly unlikely the warning would be caused by aged DEF and normal diagnostics should be followed. • DEF freezing in the vehicle tank will not cause any problems as long as the tank is not over filled. The vehicle is equipped with a heater to thaw frozen DEF when the vehicle is started and then the system will function normally.

[@irwfcm]

This all makes sense for buying new DEF and adding it to your tank. But your tank is just another storage container. Similarly to not leaving an unopened retail container of DEF around, how is it a better situation to add that DEF to your truck and just store it there instead? Also, unless you run your DEF tank dry each time, aren't you always adding new DEF on top of old DEF like they do at truck stops and service stations? I'm just trying to figure out a best practice for adding DEF to my truck, especially considering the storage time at 100 degrees (which it gets close to very often in the summer where I live) is only 2 months. It seems like I better not ever have more than 2 months worth of DEF in my truck during the summer months.

[@garyhartle7533]

What ever you decide don't run your tank dry as it will likely through you a code

[@mikehuggler4322]

Good Video. I was the victim of some very expensive Adblue from Mercedes but the seller is giving me a refund as I caught it just yesterday. Going to just get some 2019 BlueDef as I don't see any difference in some over priced DEF fluid in an originally overpriced car. Pumping out 5 gallons made in October 2016.

[@jeffjensen7718]

Good series Bro. Thx

[@MotorCityMechanic]

Morning Jeff. Thanks for the comment and for watching, its much appreciated. Make sure to subscribe and check out my other videos.

[@badguy1481]

Another Video contributor said his repair bill was 320$ when he put out of date DEF in his vehicle. They had to remove the tank....wash it out...and reinstall. The only indication he had was a check engine line and he could only drive the vehicle for a little over 200 miles more before he would be limited to 5 miles per hour. This DEF fluid could become a nightmare if all the precautions you suggest aren't followed.

[@MotorCityMechanic]

Yeah the date is important and I cant believe that companies hide the date on the container. You just never know how long it has sat on a shelf somewhere.

[@Broncort1]

Your the Scotty Kilmer of diesel...lol (that’s a good thing, btw) I guess you could mark the bottle to show how much is left. Then later if some of the distilled water evaporates, you can just add enough to get back to your mark.

[@MotorCityMechanic]

Being compared to Scotty Kilmer could be good or bad lol. Thanks for watching and for the comment

[@rockinghorselivestock2491]

Howdy David, thanks for the good video. I have been using DEF from the trucks stops without issues so far but I have never tested it either. With regard to life of DEF and high temps. What would you recommend w/ regard to maintenance tips with DEF in a truck's DEF tank for a truck that is not driven all that much and the environment is Arizona with its high air temps? I have 1/2 tank of DEF in my 2016 Ram Cummins 2500 Tradesman truck for >than 3 months and temps frequently about 80, 90, 100 degrees. I think according to the video, I should drain the tank and add new DEF? Can the DEF tank be easily drained? Thanks and happy trails, Mike

[@MotorCityMechanic]

I mentioned to another viewer that in all my research......there is never any mention of the tank DEF. So I have to surmise that it gets treated the same way so the DEF in the bottle. It can over time break down and it might eventually cause a check engine light. I personally would wait until that happened before doing any thing. For the most part.....you have control over the fluid that goes into the tank so make sure its good fluid.....once its in the tank than its out of your control as far as what happens from that point forward. If not driven much then I wouldnt keep the tank full......I would keep 1/4 to 1/2 tank. That way you will be adding good fluid as needed instead of waiting on a full tank to run down and the fluid being allowed to break down from not being used. For now....as mentioned, I wouldnt worry unless you get a related check engine light code.

[@rockinghorselivestock2491]

Thank you sir.

[@MotorCityMechanic]

Your welcome.....have a great Thanksgiving!

[@floydwilliams3321]

That’s great information man

[@Shahska1]

I read my gauge and put in fluid when I get to half. The 2.5 gallon box will fill it up

[@MotorCityMechanic]

Thanks Curtis for watching! Sounds like a great method to follow. Make sure to subscribe, if you havent already

[@Shahska1]

Question what are your thought on diesel fuel additives ???

[@MotorCityMechanic]

@@Shahska1 Personally I see no reasons for them....at least not where I am in Georgia. In the winter the colder areas of the country they might help with the jelling of the fuel but for the most part I see no real benefit. Thanks for asking Curtis

[@dannyhanke4338]

Very informative but you didn’t mention at all what happens when the def is expired or old. Is it weaker? Stronger? Even if still sealed? Does the distilled water evaporate from the tank? How will it affect the truck? Performance or emissions? More information please.

[@scootergunsmoke8542]

great advice

[@MotorCityMechanic]

Thanks Scooter. Appreciate you watching

[@TheMinnow101]

David, are you seeing issues with the DEF injector nozzle clogging/Urea crystalization ? Is the nozzle difficult to remove from the SCR and clean ? I guessing you'll get some blowback on your comment to avoid truck stop DEF as many seem to think that DEF from those places is actually fresher due to a potential larger turnover of product. BTW, great information in both Part 1 and 2 of these videos.

[@MotorCityMechanic]

I haven't seen any clogged injectors so far. Each one I unbolt from the SCR always show some signs of chrystalizing either on the tip or the port on the SCR. It's simple to remove from the SCR if need be....some have 2 10mm bolts and some older have 3 8mm bolts to remove. Thanks for watching and for the question

[@juangacho8159]

So what if I put some on my truck and in Texas it’s 100 degrees or higher it clearly means that if I don’t drive my truck enough my def would go bad right??

[@badguy1481]

Great job! You covered all the bases! But one question: I've heard the DEF can freeze at low temperatures. I've also heard that the DEF lines are close to the engine so the heat will keep the DEF lines open by melting any DEF that has frozen inside the hoses. Is that pretty much the case? In other words, I don't have to worry about DEF not being usable in below freezing weather?

[@MotorCityMechanic]

Thanks. The older DEF systems actually use coolant lines from the engine to warm up the DEF when needed to make sure it isnt frozen and on the newer DEF systems the DEF pump has a heater pad made on to it to unfreeze and frozen DEF.

[@brian42776]

my take away from this video, Screw Peak, they cryptic date is only there to screw you! I personally will refuse to buy it

[@MotorCityMechanic]

Makes no sense to hide the dates like that. If I had the choice between the Peak and one that clearly marks their bottles.....the Peak would be left on the shelf. Thanks for watching and make sure to subscribe

[@brian42776]

Thanks for the great videos!! New Ram owner, Im a Chevy convert. Loving my Cummins. Don't worry you got a subscribe from me!

[@MotorCityMechanic]

Many thanks Brian!

[@roby7140]

Julian dating is commonly used in production to make knowing the how old a given product is simpler by not having to know if the preceding months had 28, 29, 30 or 31 days. If you feel this is an attempt to "screw you" maybe you should boycott eggs and beer as well.

[@kevinsigler6747]

How about after you put it in your truck? It's 105 outside. I drive 100 miles a month. It can not be any good in the tank.

[@MotorCityMechanic]

I personally think that they are being overly cautious because if it made an issue.....there would be trucks everywhere with a failed DEF system. But thats not happening so it seems its okay in the end. When they add something new to the market they have warning after warning. We eventually over time find out what really happens and if issues come up.

[@Sicktrickintuner]

I only have used DEF fluid from my local shop at $1.00/L or $3.78/Gal Canadian

[@Sicktrickintuner]

I forgot mine comes in 1000L totes at the truck stop. Then pumped out from them.

[@mastercarp4599]

I don’t know why, my 2019 Chevy Silverado 2500 hd 6.6 comes out exhaust fluid quality poor on the dash even though I refill new DEf on it thanks

[@badguy1481]

Thanks for your previous responses. MANY thanks. Just one more question? How can we guarantee...using DEF from a bottle we buy at a store...OR...DEF from a dispenser at a Diesel station at a Truck stop..that we don't overfill the DEF tank in cold weather? Since it's my understanding that DEF freezes at 12 deg F....and locally we have many days WAY BELOW that temperature..it can crack the DEF container if the container is filled to the top. Do the spouts on the containers and the dispensing hose on a diesel station guarantee we can't fill the DEF tank beyond the freezing limit?

[@rickbrown7067]

Thanks David, I use a lot of super tec def and cannot determine when it was made. I only buy when I get t 1/2 a tank and put the whole 2.5 gal in. I’m going to try the platinum def to see if it is any better. What are your thoughts on the platinum def. Thanks again..

[@omarpulido6983]

very helpful

[@MotorCityMechanic]

Thanks Omar. Make sure to subscribe and share the videos

[@garytripp5793]

What if u keep it in a small refrigerator in shop below 60 will it last longer

[@MotorCityMechanic]

It would make it last longer for sure up to the 2 year life span.....nothing more than that however.

[@Axthex]

Awesome info, question should you refill you def when the light comes on or when the gauge reaches 1/2 or 1/4 thanks

[@douglasmikell6826]

I’ve got a beer refrigerator in my basement garage. Any problem storing the def in the refrigerator!!!

[@MotorCityMechanic]

No issues there....just make sure to leave space for the beer! lol. Thanks for the question and make sure to subscribe.

[@Scott-jf1nh]

I store mine in climate control storage unit. I bet your beer refrigerator would work fine. No freezing though.

[@harleyd500]

Interesting. I assume that the DEF in the onboard consumption container gets hot, especially on hot days and being driven over blacktop. What happens if a truck isn't used much, exposed to higher temperatures and is in the truck over 2 months or even over a year? Also you mention not buying at a pump because new DEF gets mixed with old. Doesn't the exact same thing happen in our trucks when we add new DEF over old? I just purchased a new Dodge Cummins and after reading the owners manual it doesn't address this other than to say DEF stored in temps below 90 degrees will last a minimum of one year. They make mention of consequence of using old DEF What happens if onboard DEF is consumed after it is prematurely heat aged?

[@MotorCityMechanic]

One thing about DEF is that they give us sooo many warnings and steps to follow. I too have the same question about the DEF in the tank and no one can give me an answer. So are they being overly cautious....possibly.....are the manufacturers covering that rear just incase....possibly as well. I have seen bad DEF recently and on that truck.....they had 3 different bottles in the bed of the truck....all half used and one open. I assume their issue was with the DEF they used that was in the bed. Drained and added fresh DEF and everything checked okay afterwards. All I can say is to try to the freshest batch of DEF and stick to the bottles. I rather add new to whats in the tank of the truck that would mix new and old then already mixed new and old at the pumps and then add it to my already old DEF fluid. I hope that makes sense.

[@3rdtimothy176]

Actually the injector was not that dirty or clogged and I pulled the line off the bottom of the pump and did not really see any crystallization clogged up

[@TA-tp4mt]

Should it be assumed that the storage life of the DEF includes the time it is in your truck? Living in one of those areas where the temperature exceeds 100 both outdoors and in the garage where the truck is parked, it seems like trying to control the life span of the DEF once it is in the truck is impossible. Especially if one doesn't drive a lot.

[@phprofYT]

Really wish all brands would put on the jug/box the dates like Mopar does. Really frustrating. I buy when I need it. I only use about 9 gallons a year so it isn't worth storing.

[@MotorCityMechanic]

Very true. Why hide the date? Makes no since to me

[@sonnyjones5425]

I recently purchased a gallon from Walmart and the date was on the front of the gallon jug.

[@carlvin8693]

I have recently bought the blue platinum DEF. I noticed that the Date code format is completely different than what it has been in the past,, have you noticed the date code format different than the past years. It is not what you are showing here,

[@winginitwithjohn8451]

Trickery by the manufacturer of Blue Def, by 1st having to subtract 1. most people dont know and wont check, they see a 22 and assume 2022 is the year. when in fact it could be a year old on the store shelf. Id fire the guy that thinks this "code or formula" needed is the best option for a consumer. Its nonsense, but helps sell old products. Have you had the pleasure of working on a modern diesel that mixed DEF in a fuel tank> what is the cost of that mistake?

[@5nuccs]

There is no way I’m going to do the math for piss. Moving on to another brand.

[@axercst]

i dont know if i asked this but i feel clicking in steering u turns and just entering off ramps. ram 3500 17 dually

[@cojackauto8667]

Hey David mines is the exact opposite. It’s stuck on low def fluid and I changed the harness and the pump I’m confused

[@leonardrodriguez5618]

Hey David , great video. I own an 2018 Chevy Silverado 2500hd duramax. Have used AC delco def , expensive. Which def product do you recommend less expensive but good.

[@MotorCityMechanic]

From what I can see they are all pretty good. I dont like how some the dates on the container but that doesnt mean its not good. The Blue Def is the most common you will find. I just recommend buying it from somewhere that goes through it alot like at a truck stop. Just make sure its in the box and not bulk out a pump.

[@marciewarner9225]

Hey Mr. David! Another great video! Thanx. One question I don't think you covered or maybe I missed it. Question: What's the impact on my truck if I accidentally fill the DEF reservoir with outdated/expired DEF? How much damage can happen, if any? Thanx for your help. Always appreciate you! Best!

[@MotorCityMechanic]

Outdated/expired DEF can set codes.....and if not addressed, the system can go into limp mode and eventually not start or not go over 5 mph. Otherwise nothing needs to be replaced other then draining the DEF out and the replacing with new. When the big issues come up such as contaminated DEF.....the the entire DEF system has to be replaced. Thanks Marcie for the question and flattering comments.

[@3rdtimothy176]

Hey man I got that dreaded see dealer in 148 mile code. He was throwing the P20 8D. I know the d e f fluid had to have been bad that was put in. What do I need to do take the tank off clean and is there a way to clean the pump? I clean the injector. And left fluid line off and let it hang and drove down the road and back with no fluid coming out of the line then later on I laid under the truck and feel something wet and there was liquid that have drained back out of the line while the truck was sitting there. I have a scanner from O'Reilly's and clear the codes but that dreaded message came on and here I am. 2015 Ram Mega.6.7 turbo

[@jd3953]

What do you think about the Wal-Mart brand DEF?

[@d12aurora]

Thanks and great video My question is What if I use Mopar DEF and fill my tank to 3/4 and not use my truck very much. I'm on Vancouver Island Canada not real cold winters and not crazy hot summers. What is happening with the DEF in my truck tank? Anyway to test? Hope you can answer my question.

[@MotorCityMechanic]

We have talked about it in the comments below. I feel that they are overly cautious about the fluid and the temp warnings. If it was soooo then there would be issues everywhere and really there isnt. It seems to do okay unlike the fear they seem to cause people.

[@d12aurora]

Thanks for the fast reply

[@MotorCityMechanic]

Your welcome

[@barrigany]

Great vid. Thank you! Quick question... I mistakenly filled by def tank from 1/2 to full tank right before an Arizona trip. Spent 7 days in 100+ heat. Normally, I use 1/2 tank in about 3 months. Should I be worried and drain the def tank, adding fresh def?

[@lindayarbray5096]

I don't know if anyone ask this question: Can you add distilled water to the DEF tank if check engine light is on ?

[@MotorCityMechanic]

I dont recommend it.....its not going to help and will make matters worse. When ever the check engine light is on I recommend checking to see what is causing it. It might not have anything to do with the DEF system. Thanks for the question and make sure to subscribe.

[@markfoerderer411]

Thanks for the useful information. I never realized the importance of this! Last night I ran out of DEF in my 2013 Duramax. I had just added a jug the previous month and thought I must be getting a malfunction in the warning. The truck went into limp mode (7km/hr). I drove a couple kms and pulled over and filled the DEF up. But now I’m still stuck in limp mode?

[@makeadeath]

Maybe your sensor is bad. I had my tank full but it still indicated my fluid was low