AdBlue in a Diesel Tank in Marston: Why It Occurs and How to Avoid It
Pause reading a minute when the diesel tank already has AdBlue in it: ignition off, engine off, and ring 0333 366 0103. Caught before your motor runs, it is normally a drain and a thorough flush, done where the vehicle is in Marston. The remainder of this page covers why it takes place and how to make sure it does not — useful if you are reading ahead of time.
AdBlue in a diesel vehicle: two tanks, two fillers
Many modern diesels on the roads about Marston and Sunnymead carry two liquids, not one. Diesel goes to the engine. Its own tank keeps it, and from there it goes to the exhaust, where spraying treats the gas.
Separate tanks, different fillers. Under one flap, next to each other: that is the arrangement on a lot of vehicles. Elsewhere, AdBlue's filler sits beneath the bonnet or in your boot instead. Diesel gets filled at each forecourt call-out, week in, week out. Far less often, the AdBlue side is topped up — normally from a bottle, by someone thinking about where it goes. That gap is where the slip lives.
How AdBlue in the diesel tank takes place around Marston
Three things tend to line up, and carelessness is seldom one of them.
First, the warning. Low AdBlue triggers a message from your car, and letting it run out leads to limp mode — hence a hurried top-up, perhaps before work off Oxford Road, or at The Red Lion on the way home after work.
Then, the hand reaches for the cap it knew on the old car — since a hire car, a new motor or a company car puts the fillers somewhere your last one did not.
And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, so nothing stops the tip once it has started. The same few seconds decide it, in the middle of Marston or out in New Marston.
How to tell the AdBlue filler from the diesel one
Look at these first, at a forecourt in Marston or a driveway over in Elsfield. A few seconds, no more.
- The cap. The AdBlue cap is often blue, or marked "AdBlue". The diesel cap normally is not. Read it rather than going by where it sits.
- Many motors fit AdBlue the smaller filler of the two.
- Look inside the fuel flap: plenty of vehicles have a label there saying which fuel goes where.
- The handbook says which it lives if your filler isn't next to your diesel cap: your boot, or under the bonnet.
- Check with the person who drove it last — before you leave, not when the light comes on — if you collect a hire or company car from somewhere like the car park outside Oxford.
AdBlue top-ups that never reach the diesel tank
Anywhere around Oxfordshire the light comes on, this is a routine for the day.
- Park then switch off. Not on a slope, not with your motor running, and not in a rush on the side of Elsfield Road.
- Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it does the trick.
- The diesel cap stays on. When the two share a flap, confirm it's shut before lifting the bottle.
- Gently does it, through the bottle's own spout, till it's full or the bottle is empty.
- Only then, start the car: close the cap, check once more, and make sure the diesel cap was never opened.
Discover at the second or third stage that AdBlue went in the wrong tank? That's where you stop. Step five is off limits.
AdBlue in your diesel tank already, in Marston?
The short order of things, beginning with not starting the engine. On many diesels the ignition alone runs the fuel pump, so do not switch the car on. AdBlue doesn't mix with diesel — it sinks to the bottom of the tank, where your fuel is pulled from — so do not top up with diesel to thin it.
If you're on a forecourt, whether it is the BP or the Shell, ask the staff to help push the car clear of the pump. At home around Marston? So your car stays put.
Stop as soon as it is safe then switch off, if the engine has already run. On the M40, under 10 miles from Marston, that means the next exit. Distance matters — a quick hop across Marston is a smaller job than driving under 3 miles towards Oxford — so tell us roughly how far it went.
What takes place when our technicians arrive around Marston
Wherever the car has stopped, whether by St Nicholas' Primary and Nursery School, beside Saint Nicholas Church or on your own drive, the van comes to it. What fluid was put in, the amount, and whether it ran: we ask because the answers decide both work and quote. You hear that quote on the phone, before anyone heads out.
Emptying your tank comes next, followed by a thorough flush of the system. More than with petrol, it counts with AdBlue: crystals form, certain metals are attacked, and none of it washes away on its own, however long it is left. The fuel filter is flushed, or replaced where it needs to be; fresh diesel goes in; and the car is tested. Your engine is fired up next and tested to make sure it runs smoothly, all before we leave.
Most jobs are finished in about half an hour once our engineers arrive, provided the motor hasn't run — and the pumps we use are fine on a busy forecourt and quiet at night outside a house. Paying is on the day, not upfront, and you receive the paperwork your insurer wants: an engineer report and a VAT invoice. Wrong-fuel cover is part of plenty of insurance policies — so use the wait to look at yours.
About Marston, briefly
Marston is a suburban area located on the River Cherwell in Oxfordshire, sitting at an elevation of 67 metres and approximately 1.8 miles from Oxford city centre. Marston is characterized by its semi-detached housing stock and riverside setting, with nearby places including New Marston, Summertown, and Park Town. Marston has a population of around 1834 residents and is situated within the wider Oxford urban area, about 51.1 miles west of London.
AdBlue drains about Marston, and Oxfordshire beyond
Summertown and Park Town are among the places around Marston, a residential suburb, that the same vans cover, over OX postcodes. A postcode starting OX3 0 gets our van to you fastest.
Your car remains put. The drain happens on the spot, whether a drive, a road near Royalist surrender at Oxford, or a layby towards Mill Lane Recreational Ground. Guessing doesn't help behind Saint Nicholas Church Hall, close to a boundary, or anywhere hard to pin down; ring and check.
For Marston drivers, the short version
Tip no AdBlue until you've read the cap. If AdBlue has gone in the diesel tank anyway, leave the car off then call 0333 366 0103. Petrol in Diesel drains it where it waits, anywhere around Oxfordshire.