Screen Wash in Adblue Tank...

[russy01]

Morning,

In a moment of madness I have ended up emptying a few litres of washer fluid (diluted) into the Adblue tank of a 2018 Mercedes Marco Polo 250d.

For those who want to know how this happened - I decided to reuse an Adblue bottle to mix up some screen wash and didn't label it well. Fast forward a couple months when I needed Adblue in a rush and the wrong bottle was selected from the shed!

Anyway, the vehicle was driven for a couple hundred miles before throwing an error: Adblue System Malfunction - take to dealer, vehicle will not operate in X miles. As the vehicle is under extended warranty my wife took it in, expecting a simple fix. Its at this point they discovered my error...

So, they have quoted £1000 to fix as they are saying the Adblue Tank & Pump will have to be replaced as its now contaminated, but as of yet no component failures - she pushed back asking them to simply drain, rinse and reset as both fluids are predominantly water, they wont support this.

We chucked a friend £40 to drain and refill the Adblue tank and do a simple code reset hoping it would go away, yet the warning returned immediately and we now have 100miles range before the vehicle will not operate.

Is the Washer fluid going to create havoc in the system or can it simply be cleaned up as per my uneducated suggestion?

I currently have 2 options:

- Let MB do their thing and say good bye to £1000.
- Try get hold of somebody with MB Diagnostic kit to properly reset the error and hope for the best.

Many thanks in advance.

Russ

[waynecyclist]

I would be tempted to drain, flush and refill and get the code reset with proper software.

[Fastdruid]

I suspect that the issue is downstream of the tank which is why the flush of just the tank failed.

I'd agree that the pump probably doesn't need replacing but I'd expect that the pump and all lines need flushing, then do a full reset (and it may take a dealer to do that because it is emissions related).

[MightyBadger]

waynecyclist said:

I would be tempted to drain, flush and refill and get the code reset with proper software.

Would try this for sure before saying goodbye to a grand.

[Megaflow]

The amount of ad-blue injected is tiny, if it took 200 miles to notice the change in DEF quality, then a drain and flush of the pipes and injector will probably suffice.

As you said, DEF is basically water anyway, so it is not like the lack of lubrications is going to be an issue and deposit formation in an SCR system comes from the urea in the DEF.

[Krikkit]

I would definitely get it to a Merc specialist and get them to have a crack at it - I bet with a proper flush etc it'll kick back into action.

[s p a c e m a n]

To make you feel slightly better I once filled my screen wash with adblue after mixing bottles up in the same way, instantly blind after the adblue dried on the windscreen

[Fastdruid]

So....any closure on this? Or is it still broken?

[russy01]

The local garage drained (without removing components) but struggled to clear the codes as the sensors could still detect contamination - we ran out of mileage so couldn’t just keep flushing through.

Spoke to my closest MB dealer again who refused to do anything bar replace the entire lot (>£1000) as they were dead certain everything would be wrecked - laughable! They also couldn’t provide a courtesy car at time of repair…

Called the next MB dealer who agreed that the other dealer was taking the mick and were happy to take it apart and clean it down, they also arranged an appointment within a week and provided a courtesy car.

Anyway, they did just that and found that everything was perfect, as they’d calculated only 300-400ml would have gone through the system. They cleaned it all up, reinstalled, cleared the codes and charged me less than they quoted at £370…

Amazing to witness the difference of opinion and service from two dealers just 20miles apart!! I’m currently considering buying a C63S Wagon or E63S wagon and you can probably guess which dealer will get the sales enquiry next week!!