Why It Happens and How to Prevent It: AdBlue in a Diesel Tank in Mayfair
Stop here for a moment if your diesel tank already holds AdBlue in it: ignition off, engine off, then ring 0333 366 0103. Usually, if the motor hasn't run, it is drained and fully purged where your vehicle sits around Mayfair. Nothing happened yet? Below, the rest of the page explains the why it occurs and the ways to avoid it altogether.
Why does AdBlue in a diesel vehicle need its own filler?
Many newer diesels on the roads round Mayfair and Marylebone carry two liquids, not one. Diesel goes to your engine. Kept in a tank of its own, AdBlue is sprayed into your exhaust gas to clean it.
There's a filler on each tank. Some cars put the AdBlue filler in your boot or under the bonnet; plenty more have the two together under one flap. Diesel goes in on each forecourt call-out, week in, week out. The AdBlue side is topped up far less frequently, usually from a bottle, and normally by a person who has to stop and think where it goes. The slip lives in that gap.
Mayfair: how AdBlue in your diesel tank takes place
Rarely is it carelessness: usually three things coincide.
First, the warning. Low AdBlue brings a message from your car, and running out means limp mode — so a hurried top-up, maybe before work off Hill Street, perhaps outside Coach and Horses on the way home after work.
Unfamiliar cars come second, too. Hire cars, new vehicles and company cars put their fillers in new places, and the hand reaches for the cap it used on the old one.
And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, so nothing stops the pour once it has started. St Jamess or the heart of Mayfair: it takes the same few seconds in both.
Which filler is for AdBlue, and which for diesel?
Before you pour anything, whether on a driveway in Chinatown or a forecourt in Mayfair, check these. They take a couple of seconds.
- Blue and marking: an AdBlue cap is regularly blue, or says "AdBlue", where a diesel cap normally does not. Trust the cap, not where it sits.
- Look at the size: the smaller filler neck is, on many cars, the AdBlue one.
- Open the filler flap and look for a label — plenty of cars show which belongs in each filler right there.
- Cannot find it next to the diesel filler? Then check beneath the bonnet or in your boot — the owner's manual will say where.
- Collecting a hire or company car, say at the car park outside Bond Street? Ask the person who drove the car last before you set off, rather than when the light comes on.
AdBlue top-ups that never reach the diesel tank
On the day the light comes on — anywhere you are in Greater London — a simple routine to follow.
- Not in a rush on the side of Davies Street, not on a slope, not with your motor running: park then switch off first.
- Say "AdBlue" out loud as you unscrew the cap, after you find the AdBlue filler and reading it. Silly, perhaps, but it works.
- The diesel cap stays on. Where the two share a flap, make sure it's shut before the bottle comes up.
- Slowly is best, through the bottle's own spout, until it is full or the bottle runs out.
- Close the cap and check again. Make sure the diesel cap was never opened. Only then start the car.
Spot at stage two or three that it has already gone into the diesel side? Then stop just there. Stage five is out.
Mayfair: already put AdBlue in your diesel tank?
Then the order of things is short. Do not start the motor. On many diesels your ignition alone runs the fuel pump, and so do not switch the vehicle on. Do not top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of the tank, where your fuel is pulled from.
Ask the staff to help roll the car clear of the pump if you are on a forecourt — the Esso, the Shell or somewhere else. Your own drive in Mayfair is the place it stays.
Already run? Pull over once it is safe, then switch off. Mayfair lies under 10 miles from the M1; on it, use the next exit. Tell us about how far it went: a run towards Westminster, under 3 miles away, is a bigger job than a short hop across Mayfair.
Our arrival in Mayfair, and what occurs next
By St George's Hanover Square CofE Primary School, near Clive of India or on your own driveway: wherever the vehicle has stopped, our engineers come to it. Our technicians ask what got in, roughly how much, and if it has run, because those answers determine this work and the quote. You hear that quote on the phone, before anyone heads out.
Draining your tank comes next, followed by a thorough flush of your system. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own. A test comes at the end: before that, clean diesel is added, and the fuel filter is flushed or replaced as needed. Your engine is started next and tested to be sure it runs correctly, all before we go.
If your engine has not run, the majority of jobs take about half an hour once we're there, using pumps that are fine on a working forecourt and quiet enough to use outside a house after dark. Nothing in advance; you settle up that day. Afterwards, the VAT invoice and a report from the engineer are handed to you for your insurer. It's worth looking at your policy as the van travels to you: misfuelling cover is included with plenty of policies.
About Mayfair, briefly
Mayfair is a suburban area in central London, situated near the River Thames and close to several major landmarks. Mayfair sits at an elevation of around 33 metres, with many of its residents living in flats. Mayfair is bordered by nearby places such as St James's, Hyde Park Corner, and Soho, and is within walking distance of Westminster. Mayfair has a population of approximately 3632 people.
AdBlue drains in Mayfair and across Greater London
Over W1J postcodes, the teams covering Mayfair — a residential suburb — work the surrounding locations too, Soho and Hyde Park Corner included. A postcode starting W1J 5 gets our van to you fastest.
Shifting your car is not needed. A driveway, a lay-by on the way to Berkeley Square, a side street near The Berkeley Square T-Rex: our engineers drain the vehicle where it stands. If you're close to a boundary, or somewhere hard to explain like the back of George Canning, ring and ask rather than assuming.
The short version for Mayfair people
First, the cap; after that, the tip. If AdBlue has gone in the diesel tank anyway, leave it off then call 0333 366 0103. Petrol in Diesel empties it where it stands, anywhere across Greater London.