AdBlue Overfill

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BillNick

New Member
Joined
Nov 17, 2020
Messages
5
Location
Kent
Car
2015 E220 Bluetec Cabriolet A207
Hi all,

I recently had the Nox sensors replaced on my 2015 E220 Bluetec (A207) under Mercedes recall/warranty.

Before I had that done, I got the usual AdBlue low message on the dash and added 10L of AdBlue.

Today I decided it might need another 10L what with the tank being 25L in total, so I put that in today.
Then, after just a couple of miles driving the EML light came on. Obviously haven't had time to get the code read yet which I will do in a couple of days.

In the meantime, I am now worried that I might have overfilled the AdBlue if Mercedes also topped it up when they did the Nox sensors?.
However, I am told that AdBlue is treated like a consumable same as fuel and so its not filled as part of any servicing etc, so I assumed they didn't put any in.

The tank took the full 10L today and did not overspill, however i could see the level was almost at the top and probably just short of over spilling.

Can an overfill cause issues, even if the amount I put in did NOT spill over the top?

Thanks
Billy
 
Overfilling doesn’t cause any problems. On models with the tank in the boot any overflow runs onto the ground under the car. For fill points adjacent to the diesel tank cap there is a drain hole in the bottom of the flap recess to route spills away under the car too.
 
Oke doke thanks.

After reading a few threads today someone said you must run the engine whilst filling, which I find hard to believe as you wouldn't do that if you was filling at a petrol station with an AdBlue pump....?

And also, cycling the ignition a few times before driving too?

Neither of which I did today :-(

Just filled, started and off I drove....
 
I wouldn't fret about it. It's very likely something hasn't been set up quite right with the recall work
 
Straight onto Merc tomorrow me thinks....
 
Hi all,

I recently had the Nox sensors replaced on my 2015 E220 Bluetec (A207) under Mercedes recall/warranty.

Before I had that done, I got the usual AdBlue low message on the dash and added 10L of AdBlue.

Today I decided it might need another 10L what with the tank being 25L in total, so I put that in today.
Then, after just a couple of miles driving the EML light came on. Obviously haven't had time to get the code read yet which I will do in a couple of days.

In the meantime, I am now worried that I might have overfilled the AdBlue if Mercedes also topped it up when they did the Nox sensors?.
However, I am told that AdBlue is treated like a consumable same as fuel and so its not filled as part of any servicing etc, so I assumed they didn't put any in.

The tank took the full 10L today and did not overspill, however i could see the level was almost at the top and probably just short of over spilling.

Can an overfill cause issues, even if the amount I put in did NOT spill over the top?

Thanks
Billy
Hi. S a taxi driver I use to top mine up once a month. Finally my tank sensor stopped reading and got stuck on 5900 miles. The emg light came on and code said it was my adblue tank sensor. Took it into garage and tank was replaced under warranty. Do not keep filling up your tank and wait until the sensor tells you to. Adblue crystallisted in the tank messing up the tank sensors
 

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