drgeeforce

Noticed my 2010 GL350 Bluetec was having white spots on the back of the SUV. Washed off with no ill effects. Looking at the back of the SUV, noticed white paint-like stain underneath AdBlue tank. My heart dropped, I thought to myself, another grand in repairs.
I just had the dealership replace the heater after the code went off and failed smog testing. It was 3days $1200 in repairs and no loaner to boot.

I figured there might be a puncture in the ABS tank from road shrapnel or likewise. I crawled underneath and saw the tank had a protective shroud and AdBlue was leaking from the weep holes.

By some glint of fortune it dawned on me to check the filler neck in the tank.


It was caked in DEF fluid and crystallized. Had the dealership left the cap off? or was there sabotage to get me back into the dealership so I can pay for a new tank costing thousands of dollars?

Nope I noticed there was an O-Ring at the filler neck.

I was hopeful that I could stave off thousands in repairs by just a 2 cent O-Ring, blessed be the auto repair gods.

I took a small screwdriver with a blunted tip and removed the O-Ring, replaced it with one of similar diameter but more thickness, put some silicone O-Ring grease, and I was done.
I washed off the crystals with a slow stream from the garden hose onto my lawn(grass loves urea as a nitrogen source). The water and dissolved crystals went through the weep holes and I was done. Put everything back and I'm keeping my fingers crossed.

I'll repost in about 3 weeks to update.

alx

It is possible that the tech was not careful refilling the tank and splashed a lot. You might or might not had a leak. But... If a new seal makes you happy- so be it