--- title: Oval: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/oval-greater-london/ location: Oval county: Greater London latitude: 51.481300 longitude: -0.119700 service: AdBlue in a Diesel Tank updated: 2026-10-17 --- # AdBlue in a Diesel Tank in Oval: Why It Happens and How to Stop It Leave your engine and ignition off then phone 0333 366 0103 first — the rest can wait if AdBlue is already in your diesel tank. Caught before the engine runs, it is usually a drain and a thorough flush, done where the vehicle is around Oval. If you are reading before it has happened, the remainder of this page is about why it happens and how to make sure it doesn't. ## Why does AdBlue in a diesel vehicle need its own filler? Many current diesels on the roads about Oval and Victoria carry two liquids, not one. Diesel goes to your motor. AdBlue goes to the exhaust, where it is sprayed into the gas to clean it, and it lives in a tank of its own. Each tank comes with a filler of its own. On a lot of vehicles the two sit side by side under the same flap; on others the AdBlue filler is in the boot or under the bonnet. At the pump, the diesel side is topped up constantly. The AdBlue side is filled far less often, normally from a bottle, and usually by somebody who has to stop and think where it goes. That gap is where the slip lives. ## Oval: how AdBlue in the diesel tank happens It's seldom carelessness. Three things tend to line up. On a drive off Meadow Road before work, or in the car park at The Fentiman Arms on the way home: that is where the hurried top-up takes place. What is the reason for the rush? As AdBlue runs low your car tells you, and if it's gone, limp mode follows. The old car's filler is where your hand goes — but a rental car, a new motor or a company car keeps the fillers somewhere else. That's a second factor: an unfamiliar car. Lastly, the spout fits: a diesel filler or AdBlue filler, it goes in as readily, and once the tip starts, no part stops it. It's a few seconds, whether out in South Lambeth or right in the centre of Oval. ## Telling the AdBlue filler from the diesel filler A few seconds is all the checks take — so check them before you pour anything, on a driveway in Millbank or a forecourt in Oval. - Position misleads; the cap does not. AdBlue ones tend to be blue or bear the word "AdBlue" — diesel caps normally do not. - On plenty of vehicles, size tells: AdBlue gets the smaller filler neck. - A label inside the fuel flap frequently says which fuel goes where, on many motors. Look for it. - The handbook. If your filler isn't by your diesel cap, it is in the boot or under the bonnet, and the handbook says which. - Picking up a hire or company car, say at the car park outside Vauxhall? Check with whoever drove the vehicle last before you set off, rather than once the light comes on. ## How to top up without AdBlue in the diesel tank On the day the warning appears — wherever you are across Greater London — a simple routine to use. - Not in a rush on the side of Meadow Mews, not on a slope, not with the engine running: park then switch off first. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it works. - Leave the diesel cap on. If both sit under one flap, check your diesel cap is still closed before you lift the bottle. - Tip slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Close the cap and check a second time. Make sure the diesel cap was never opened. Only then start the vehicle. Stop there if you find, at stage two or three, that you have already poured into your diesel side. Skip step five entirely. ## Put AdBlue in your diesel tank around Oval already? Brief list, then. First: your motor stays off. Leave the ignition off as well, since on plenty of diesels it alone starts your pump. AdBlue doesn't mix with diesel — it sinks to the bottom of your tank, where the fuel is sucked from — so don't top up with diesel to thin it. At a forecourt — JET, Texaco or another — the attendants will normally help push the car clear, if you ask. On your own drive in Oval? So the car remains put. When your motor has run by now, stop somewhere safe and switch the vehicle off. Oval sits under 10 miles from the M4; there, use the next junction. Tell us about how far it went: a run towards Westminster, under 3 miles away, is a bigger job than a short hop across Oval. ## Oval: what takes place when our engineers get there The van comes to the car anywhere it stopped — your own driveway, beside Calvary Church of God in Christ, or outside St Stephen's Church of England Primary School. Both the work and the quote rest on three replies — what fluid, which quantity, and whether it's run — so our engineers ask. During the phone call itself, you hear the quote — before dispatch. After that: draining, then a thorough flush of the whole system. Not like petrol, AdBlue leaves crystals and eats at certain fuel-system metals, and neither clears out by itself. Hence it counts more. The filter cleaned or, where it must be, replaced; fresh diesel in; and then a check of the vehicle. We do not leave until it has been started and is running correctly. Using pumps safe on a working forecourt and quiet enough to use outside a house at night, most jobs in which your motor has not run need about half an hour after our engineers are there. No money in advance; you settle up on the day. Afterwards, a VAT invoice and the report from the engineer are handed to you for the insurer. Plenty of insurance policies include misfuelling cover, so it is worth checking yours whilst we are on the way. ## About Oval, briefly Oval is a suburban area in the London Borough of Lambeth, situated on the south bank of the River Thames. Oval sits at a low elevation of around 8 metres, close to the river and near the cities of Westminster and London. Oval is surrounded by other suburban areas, including South Lambeth, Kennington, and Vauxhall, and is characterized by a high proportion of flat dwellings. Oval has a population of approximately 24,954 people, making it a densely populated residential area. ## AdBlue drains across Greater London, Oval included As a residential suburb, Oval has the same vans as nearby places — Kennington, Vauxhall — right through SW postcodes and the surrounding area beyond. A postcode starting SW8 1 gets our van to you fastest. The vehicle remains where it is. Our technicians drain it where it is — a side street near Mother and Children Playing, a lay-by on the way to Lavender Garden, a driveway. Guessing won't help at the back of Boys Playing Football, close to a border, or anywhere hard to describe; ring and ask. ## Oval drivers: the short version Before you pour, read the cap. Petrol in Diesel empties it on the spot, anywhere around Greater London, if AdBlue has gone in your diesel tank anyway — and so leave the car off then ring 0333 366 0103.