--- title: St Tudy: AdBlue in a Diesel Tank? Don't Start canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/st-tudy-cornwall/ location: St Tudy county: Cornwall latitude: 50.554680 longitude: -4.730830 service: AdBlue in a Diesel Tank updated: 2026-10-17 --- # Don't Start It: AdBlue in a Diesel Tank in St Tudy If AdBlue has got into the diesel tank, keep the motor off and leave the ignition off. Chemically, AdBlue is simply urea in water. Not like fuel, it neither ignites nor mixes, and nothing starts till your motor sucks it round. In St Tudy, AdBlue in a diesel tank found before your motor runs normally means a drain and a thorough flush, just where your car is. No step comes before calling 0333 366 0103. ## St Tudy, AdBlue in the diesel tank: what to do straight away To do: - Take the keys out, so nobody switches your ignition on. - Near moving traffic? Then put the hazards on. - Keep the receipt or the empty bottle, and so you can tell us what got in and roughly how much. - The van finds you quickest with a postcode starting PL30 3, or just the name of a street close by, so phone from the spot. Not to do: - No starting the engine — not for a second, not to reposition your car. - Don't switch the ignition on. On many diesels that alone runs the fuel pump. - AdBlue doesn't mix in diesel — it separates out — so adding extra fuel will not thin it. - Even a short stretch along Chapel Road is too far to drive the car. - Beside the road, don't attempt emptying it yourself. The staff on duty at any St Tudy filling station — the Esso among them — will usually help rolling it clear if you ask. On your own driveway, don't move it at all. ## What does AdBlue do in a diesel tank? Not the engine but your exhaust is where AdBlue belongs. It goes into its own tank and is sprayed into the exhaust gas to clean it. A fuel pump is not made to take it, and AdBlue was never intended to go through one. Fuel mixes; AdBlue, once poured in, won't. Its behaviour is nothing like diesel's. Heavier than diesel, it sinks and collects underneath it — the same place the intake draws from. When your system runs, the AdBlue is top of the list to be pulled through. Until then it waits underneath the diesel, and that is how a car topped up in Wenfordbridge last night and not started remains the simple one, as long as nobody touches the key. Once it is drawn in, the damage takes two forms. As its water goes, the urea left behind crystallises, and the crystals block filters and settle in fine passages. And it is corrosive to some of the metals a fuel system is made from, and so it keeps working on the parts it reaches for as long as it stays there. A car left standing in St Tudy with AdBlue already in its lines is worse by the morning; one with AdBlue just in its tank is not. Diesel protects the high-pressure pump and every injector as it passes; water offers no lubrication, and that is a second form of harm. ## Why AdBlue in a diesel is commonly more major than petrol Petrol put into a diesel on Valley Truckle Filling Station's forecourt leaves the fuel thin — that is the main fault. No damage is done as long as it stays put, mixed into your diesel — only once the engine works on it. AdBlue in a diesel is a fault of the wrong substance altogether. Since it doesn't burn, running it through isn't an option. It does not stay mixed, and so it cannot be diluted. And crystals and corrosion don't wash out with the next tank of fuel. That's why the flush counts more with AdBlue than with petrol, and why starting the motor "to see" costs more here than almost anywhere else, whether your car is in Lower Lank or the middle of St Tudy. The same good news holds as with petrol. If your engine hasn't run, the AdBlue is still in the tank, and the tank is the quickest part of a fuel system to clear, wherever around Cornwall the vehicle is standing. ## AdBlue in a diesel tank around St Tudy: how it ends up there It is not deliberate. Plenty of cars have the AdBlue cap beside the diesel one, occasionally behind a single flap, and mixing them up is easy after dark. A container bought while heading home and poured in outside the house, rather than at the filling station, is the typical route. It tends to take place in a few familiar ways. A warning light comes on during the school run, and the top-up occurs in a hurry outside St Tudy CofE Primary School. Someone tips the bottle in at home, right off Wadebridge Road, as the day ends. Or a driver unfamiliar with that flap refills the car in dim light, parked in the car park by The St Tudy Inn. The least known cars see it the most — rentals, brand-new ones, company ones, and the spare vehicle of a family with one of each fuels. Anywhere around Cornwall, St Tudy included, the slip doesn't change, and neither does the first response: leave it off. ## St Tudy: started the motor with AdBlue in the diesel tank? Then the AdBlue has left your tank. Given any running, it travels to the injection pump and every injector, after passing via the fuel filter and lines. Watch for lumpy running, smoke, lost power, lights on the dash, or a cut-out — coming back from St Tudy Playing Field, perhaps, or midway across St Tudy. Pull over when safe. Turn off. Keep it off instead of testing it again. More of that is pulled through with each start. If you were on the M5, over 50 miles from St Tudy, come off at the next exit and stop somewhere sensible instead of pressing on. Mileage counts: each mile carries the AdBlue deeper into your system, and so driving towards Truro, under 25 miles away, gives a much bigger job than crossing St Tudy to the car park by St Tudy Church. Tell us roughly how far it had come. Our technicians do all of the flushing where the vehicle has stopped, and once the engine has been run there is more of it. When it is caught soon, lasting damage is very uncommon. ## Draining AdBlue in a diesel in St Tudy: what it takes We come to the car, wherever it has stopped in St Tudy: a side street close to St Tudy Methodist Church, a drive, a lay-by or a forecourt. Three replies shape the work, so before anything else our technicians ask what was put in, roughly the amount, and if the engine has run. Right there, your tank is then drained, and all of the polluted diesel and the urea leave at once. A full flush counts much more after AdBlue than after petrol, because residue won't wash away by itself. Testing your vehicle comes at the end, after clean diesel is added and your filter gets flushed or, if necessary, swapped. If the engine hasn't run, most jobs take about half an hour once our technicians are there. The pumps are explosion-proof, safe on a working forecourt and quiet enough to use outside a house at night. Fresh diesel goes in to bleed the fuel system, and that's the final step. Whether it is a parking bay outside Bodmin Parkway or a driveway around St Tudy, that is where we fire it up and you drive off. Before leaving, our engineers make sure it's running smoothly with fresh diesel in. The entire job is done where your car is, so it never has to go to a workshop. Afterwards, there is paperwork for your insurer: a VAT invoice and a report from the engineer. ## About St Tudy itself St Tudy is a small village in inland Cornwall, situated approximately 110 metres above sea level. St Tudy lies near the villages of Trevenning, Lank, and Gam, and is about 24.6 miles from the city of Truro. St Tudy has a population of around 679 people, predominantly living in detached houses. ## AdBlue drains across Cornwall, St Tudy included Over the PL postcode area, the teams answering AdBlue call-outs around St Tudy serve much of Cornwall as well, Trevenning, Lank and Gam included. Guessing won't help close to a county line or anywhere hard to pin down; ring and ask. A van that comes to you suits St Tudy, a rural village: you have no need to take your car to us, since our technicians empty it on the spot, on a drive, a residential street, a car park or a forecourt. ## What AdBlue in a diesel tank costs to put right around St Tudy Not one single price would be honest, since each job differs. The cost moves first with how long, if at all, the engine has been running, and next with the quantity of AdBlue that was put in. After that it depends on where the car is and whether our van can reach it safely, which is easier on an open driveway than in a tight gap behind St Tudy Village Hall. Before any figure, never afterwards, each enquiry from St Tudy opens with three checks: the fuel, the quantity, and whether it ran. The answers turn a range into a straight quote. Priced on the call before the van sets out, it is paid for on the day — card or phone, no deposit. Misfuelling cover is part of plenty of insurance policies, so it pays to look at yours before the van arrives. ## Still alongside your car in St Tudy? Then, the best thing to do with the car is to not touch it. Motor off, keys out, ignition off. Tell us it was AdBlue, roughly what quantity, and if it ran, on 0333 366 0103. From there Petrol in Diesel handles it, across St Tudy or anywhere in Cornwall.