DEF Tank leak

Taking our 2010 NCV3 out on its first major semi-converted-status trip (Philadelphia/Colorado/Seattle/Wisconsin/Philadelphia). Things went well for the big 1300 mile haul from Philadelphia to Colorado (2 days). But I had a wierd feeling during the day we rested up at a state park about the white on the back passenger side tire.

Today, we did a big crossing of south-western Colorado (many passes, including Monarch, with an astounding 20mpg average!). Somewhere just NW of Telluride we stopped for a photo, and I noticed a strong ammonia smell by the slider door as I was getting back in. Looked down, liquid clearly leaking from the vehicle. Bend down to take a look - DEF spillage evident all over the DEF tank side and bottom. YIKES!

No option other than to continue driving. We finally got into Moab. I took another look. No leakage occuring anymore, but the entire tank bottom is covered in ammonia crystals. I felt sure that when I first noticed it the leak was the tank *side*.

OK, I am pretty sure that this is a serious condition. But does anyone have anything to offer? For a start, does the warranty cover the DEF tank and if so for how long? The DEF warning light has not shown up so far.

I'll also take pointers to possible sprinter service shops pretty much anywhere in Utah except the extreme NE and SW quadrants.

I wish I could post pictures but it was too dark by the time we got online and settled enough to take a picture.

Yes, sounds like you need to get to a Sprinter service center, MB, Freightliner. I don't know anything about that area. I'm sure you will get others to chime in.

I would also stop at a Walmart or someplace and pick up the 2.5 gal container of DEF and have it handy just incase you start getting the count down to the bottom of the tank. Also, if you can see where it's leaking, duct tape might be a temporary solution.

Good luck.

stew

I have a 2010. There is a software update for the heaters in the DEF tank
https://sprinter-source.com/forums/showthread.php?t=24807
Being this is your 1st major drive since your conversion,maybe the fluid froze up and cracked the tank( in the winter)

You might consider washing the underside of your van....DEF is corrosive!

Old Crows said:

You might consider washing the underside of your van....DEF is corrosive!

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That was my first thought too. It really likes to attack copper wiring so x100 on that suggestion from me.

Maybe run through a car wash that sprays the bottom of the vehicles.

Duct tape may not stick well as a temporary patch. I'd consider using a pool patch designed for underwater application. It has been mentioned here that JB Weld has an epoxy formulated for plastics.

I have no idea whether it is covered under warranty. I can't imagine it would be considered a wear part.

Good luck. vic

Larry Miller Mercedes Lindon Ut, 180 miles north from Moab and the only other option you have is Freightliner Sprinter in SLC Utah, about 215 miles north of Moab.
Both sell alot of Sprinters and just off I-15

K-9 SPRINTER said:

I have a 2010. There is a software update for the heaters in the DEF tank
https://sprinter-source.com/forums/showthread.php?t=24807
Being this is your 1st major drive since your conversion,maybe the fluid froze up and cracked the tank( in the winter)

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given that this just happened and temperature has been between 97F and 60F for the whole trip, this seems unlikely thanks for the thought, though.

PaulDavis said:

given that this just happened and temperature has been between 97F and 60F for the whole trip, this seems unlikely thanks for the thought, though.

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hmmmm

PaulDavis said:

It is too cold here for any conversion work at all. Metal primer paint won't cure, contact adhesive won't cure, sealants won't cure, moisture won't evaporate. And there's another 6-8 inches of snow+ice due tonight and tomorrow.

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I did say ... that maybe it happened in the winter ......................

PaulDavis said:

Taking our 2010 NCV3 out on its first major semi-converted-status trip (

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since the conversion (that you were working on in the winter) you may not have noticed the leak with little driving

Paul,
The DEF tank and the entire SCR/DEF system should be covered under your 100k emissions warranty.
In RV's the DEF tank is often hidden under/behind things added on by the RV upfitter.
One wonders if perhaps the installation of some RV specific item by the RV upfitter could have punched
(or drilled if they were not careful) a hole in your DEF tank.
Then it would not be a Mercedes Benz warranty issue, but something you would need to have the RV upfitter
pay for as it was their mistake that caused the problem.
As suggested, wash it down, make sure there is some DEF (2.5 gallons minimum) in the tank, and take it to an
authorized Mercedes Benz Sprinter dealer.
It's possible the leak is near the top of the tank, so keeping it completely full may not be a good idea until
the tank is repaired, but OTOH you can't run it any distance with no DEF fluid or you will get the warnings
and the potential for a complete engine shut down.
If it turns out to be something related to the RV specific installations, get lot's of photos as Benz will not cover the
RV upfitters mistakes (or even the labor to remove RV specific items/assemblies that are in the way of repairing or
replacing your DEF tank).
Then use the photos to work on the RV upfitter to pay for the additional cost of removing and replacing the RV
specific items/assemblies.
Hope this helps,
Roger

sailquik said:

Paul,
The DEF tank and the entire SCR/DEF system should be covered under your 100k emissions warranty.
In RV's the DEF tank is often hidden under/behind things added on by the RV upfitter.
One wonders if perhaps the installation of some RV specific item by the RV upfitter could have punched
(or drilled if they were not careful) a hole in your DEF tank.
Then it would not be a Mercedes Benz warranty issue, but something you would need to have the RV upfitter
pay for as it was their mistake that caused the problem.
As suggested, wash it down, make sure there is some DEF (2.5 gallons minimum) in the tank, and take it to an
authorized Mercedes Benz Sprinter dealer.
It's possible the leak is near the top of the tank, so keeping it completely full may not be a good idea until
the tank is repaired, but OTOH you can't run it any distance with no DEF fluid or you will get the warnings
and the potential for a complete engine shut down.
If it turns out to be something related to the RV specific installations, get lot's of photos as Benz will not cover the
RV upfitters mistakes (or even the labor to remove RV specific items/assemblies that are in the way of repairing or
replacing your DEF tank).
Then use the photos to work on the RV upfitter to pay for the additional cost of removing and replacing the RV
specific items/assemblies.
Hope this helps,
Roger

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He doesn't have an RV from an upfitter, its a homemade conversion on a used work van that he purchased https://sprinter-source.com/forums/showthread.php?t=30991

Thanks to everyone who replied. We made it to Seattle without visiting a dealer - I called Freightliner in SLC but they couldn't promise to work on the problem on the schedule we needed. Picked up an extra 2.5 gallons of DEF just in case, but we had no warning lights. The leak is definitely on the top of the tank, and I think enough has leaked out that we just get a little spillage now and then when we swerve fairly fast. I washed the underside of the van in Moab with a pressure washer.

Will be in Seattle for 11+ days, so I will find a dealer here and get them to take a look. I am not going to accept anything other than warranty work. To have this tank leak is unacceptable. I have never drilled anything near the tank, so they will have to work hard if they want to suggest that it is somehow my doing.

K-9 SPRINTER said:

hmmmm I did say ... that maybe it happened in the winter ......................

since the conversion (that you were working on in the winter) you may not have noticed the leak with little driving

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We drove to Ohio (14 hours each way) in May. We also drove to Colorado (1800 miles) before noticing the issue. I really don't think that cold weather has much to do with it. If I was to make a guess without seeing the top of the tank, I'd guess either the sensor seal is broken or the tank actually cranked.

Leakage a can occur from various parts of the DEF system as there are a few potential leak points.
Notably the access ring into the tank and its seal could be leaking.
Or
The HP pump sat on the tank top and the suction return element is held by three 6 mm allen screws, sealed by two O rings it could feasably be leaking as about 5500 kp is the pump pressure when operating.

Maybe the output feed plastic feed hose from the pump to the DEF injector is misplaced or leaking!
Equally there is a leak at the DEF injector.
Of course the tank could be split or damaged, even punctured by a careless bodybuilder fitting tanks and steppers under the tank if it is a motorhome. (I have had one of these in the shop a few weeks ago!)

Of course do take into account that according to one of my local MB dealers; they are changing no fewer than 25 DEF tanks etc on average per month.
That is a fairly large campaign given the US parc and confirms that from my experiences over the last year the DEF system on the late model Sprinter is fraught with service problems.
Best of luck with your van and the dealer
Dennis

Dennis, thanks so much for the info. This makes me feel much more equipped to deal with the local dealer tomorrow. I did the conversion of this vehicle and I can testify that I never put anything through the floor in the area above the tank. Still "pristine" factory floor.

PaulDavis
Glad to be of help & keep us posted as to how it all turns out.
Cheers Dennis

lindenengineering said:

Leakage a can occur from various parts of the DEF system as there are a few potential leak points.
Notably the access ring into the tank and its seal could be leaking.
Or
The HP pump sat on the tank top and the suction return element is held by three 6 mm allen screws, sealed by two O rings it could feasably be leaking as about 5500 kp is the pump pressure when operating.

Maybe the output feed plastic feed hose from the pump to the DEF injector is misplaced or leaking!
Equally there is a leak at the DEF injector.
Of course the tank could be split or damaged, even punctured by a careless bodybuilder fitting tanks and steppers under the tank if it is a motorhome. (I have had one of these in the shop a few weeks ago!)

Of course do take into account that according to one of my local MB dealers; they are changing no fewer than 25 DEF tanks etc on average per month.
That is a fairly large campaign given the US parc and confirms that from my experiences over the last year the DEF system on the late model Sprinter is fraught with service problems.
Best of luck with your van and the dealer
Dennis

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Dennis, you are correct about this underlined comment. I went through this dance for thousands of miles before SunMotors of Mechanicsburg, PA finally rectified the problem! It was the upstream and downstream NOx sensors not agreeing with each other...

I am thankful for this establishment and have after 8000 miles had no problem..still have another 4000 to go before coming home. Of course I am keeping a keen eye on replendishing additional DEF as we travel.

cheers....

Yes well quite frankly the whole thing is a bloody service disaster, made worse by the manufactures playing poker with service information and the ability to service/repair the blessed system using a proprietary scanner.

Its made by Bosch and most are of Czech origin if that is of any conclusion.
All of this reminds me of the introduction of cats on cars in the 1980's; that too was a service nightmare due to the basic design of the engine that was made to accept carburetors. It took the trade about ten years to get it right, I just hope it doesn't take that long with the DEF system on a modern diesel. I will be long into my Seventies by then and hoping to be surfing in Cost Rica!
But if it keeps up like this I will be dollars in and on the beach in Monte Carlo or Cannes.
Take care
Dennis

Mercedes Benz of Seattle handled the issue. The DEF pump was leaking through the body. All handled under the federally required 5 yr/100,000 mile warranty, zero cost to me. They had some problems getting the new pump started, caused (they thought) by DEF-caused corrosion of various things. Took all day to fix, but I'm a happy camper again for now.