--- title: Fuel Drain in Portaferry — Petrol in a Diesel Car canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/portaferry-county-down/ location: Portaferry county: County Down latitude: 54.380900 longitude: -5.548600 service: Petrol in a Diesel Car updated: 2026-10-12 --- # Petrol in a Diesel Car in Portaferry With the tank still holding the petrol and the engine not yet started, almost every job needs only a drain, so leave the engine off. That outcome is settled in the minutes right after the fill-up, rather than by the amount that was put in. Across Portaferry and the rest of County Down, Petrol in Diesel drains the vehicle and cleans it where it is, whether at a roadside, on a driveway or at a forecourt. Call us so our technicians can tell you what happens next before you try any more. ## What next? Petrol in a diesel, step by step - Feed a petrol motor diesel and it will usually fail to run at all, and so the motorist stops there and so does the harm. Feed a diesel petrol and the thing starts, it ticks over, it drives off — fine for a couple of miles. People have that reversed, which is the thing they get wrong about petrol in a diesel in particular. So don't crank it. And having started, do not believe it: that fuel system is wearing as you drive. - Diesel ignites, and before it combusts it greases — that injection pump, the injectors. Petrol manages only the burning. So leave your ignition alone also: turning it on is frequently sufficient to prime that system, and priming pulls petrol from the tank into precisely those components. - That advice supposes a diesel fuel system handles petrol by percentage. It won't. Tip diesel on top and nothing at all is taken out; what you end with is a fuller tank of the same mixture. And no, the octane makes no difference — super unleaded is just petrol. - Stay where you are if you sensibly can. A motor that has never moved is the simplest one to sort out, and we would much rather drive to a difficult place than have it started. If you're stopped on the verge on B7041, switch those hazards on then keep it there. - Check where you are before ringing. A postcode starting BT22 1, and the name of whatever is closest to you. Otherwise our van circles instead of arriving. - Call 0333 366 0103. Say what was put in, about how many litres, plus if the motor has fired. These three details decide the entire call-out. Do not take it home. Petrol-thinned diesel has passed through your high-pressure pump in real quantity on the road in, and the trip back would more or less double that for nothing at all. Phone us — the platform is fine. There is no need to stand over your Volkswagen Passat outside the nearest station while the work gets done, and we'd much rather hear from you tonight than discover on Monday. ## On the forecourt: draining petrol from the diesel It begins at a pump, mostly. Regularly the work finishes at one as well. We work on petrol station forecourts routinely, with the station's agreement, so if you're still at the nearest petrol station that is usually where this drain happens. The forecourt is the only spot it is halted before your motor has started. Everywhere else — a car park, a private drive, a lay-by — your car was fired up and moved to get there, which means fuel was sucked from the tank, through the fuel filter then into your high-pressure pump. That is not a disaster, and our engineers can still sort it out where it sits. It does mean the fuel lines and your filter need cleaning as well as your tank, and that is determined by the few seconds between seeing your receipt and going for the key. Wheel the vehicle out of the way if the staff volunteer, and they normally will. The next motorist gets by the pump, and that's worth doing. Cranking the car just to roll four car lengths is not. ## Portaferry and the areas next to it Being a coastal area, Portaferry gets a regular visit, whilst the places close by come with it on that same journey: Strangford and Cloghy, Killyleagh and Ballyhornan, Shrigley. Not on the list? It means nothing. The names above are just the nearest few, and the majority of places around County Down have a page of their own somewhere on our site. Ring us and enquire rather than presuming, particularly if you are on a border or anywhere the satnav gets wrong. The ground this page covers is on our map. Kerbside, forecourt, driveway, car park: the lot is ground we work on, and none of it requires your car to travel to us. A diesel pump delivers fuel on demand, and a frantic morning drive demands plenty — so three miles in the Skoda Octavia seems like nothing and isn't. Twenty to nine by the local primary school, already late, the receipt in your hand showing unleaded: hazards on, ignition off, phone us. ## Broken down at the kerbside around Portaferry Some drivers find no sensible place to pull over whatsoever. Set off, then realised? Landed on the verge of B7065, or parked in some lay-by with the hazard lights flashing? That's a common call here. Not a rare one. Wait by the car while it is sensible to be inside, but out of it if it's not. It will often oblige. A diesel running on petrol limps along perfectly willingly, and that is the trouble: restart the vehicle to get to somewhere handier and the mixture goes further into your fuel system with every mile covered. However tricky the location, it is no trouble for us to come to it, and that is far better for your car than pressing on. Your BMW 3 Series remains where it is in the car park by the pub in the village for the whole job, which usually runs like this. First we ask what was put in, roughly how much, and whether your engine has run since, given that much of the work rests on those replies. The tank is emptied of the polluted mix, the fuel lines are flushed, and the filter comes off if it is a serviceable one. With clean diesel in and the fuel system bled, your car is fired up and checked, and once it's running correctly you set off. ## Already run it? Petrol in a diesel after a few miles Here is where the M77 counts, over 50 miles from Portaferry. A wrongly fuelled diesel will usually get you onto it and some way along before anything feels wrong, and the signs when they arrive are normally a loss of power, an uneven idle and smoke rather than a tidy stop. Get off at the first safe exit, switch off, and don't start the car to move it. Long trip? Anything close to the under 25 miles to the nearest city and you should assume the lot — filter, pump, injectors, all of that got to by the petrol. Say that on the call, as it changes what goes in our van. ## All about Portaferry Portaferry is a small coastal locality in County Down, situated on the shores of Strangford Lough. Portaferry sits at a low elevation of around 7 metres, with the surrounding landscape dominated by the lough and the nearby villages of Strangford and Cloghy. Portaferry is characterized by its terraced housing and quiet residential atmosphere, lying within commuting distance of Belfast. Portaferry is also close to other nearby places such as Killyleagh, and is around 300 miles from London. ## What comes next when our engineers get to you around Portaferry - Our engineers check what got in, how much, and if the motor has run. The responses shape the work, which is why we ask before quoting. - Away comes the polluted mixture. - Our technicians rinse the lines and clear the filter, so what is remaining in the system isn't what caused the trouble. - Our technicians pour clean diesel in and bleed the system. - The motor is fired up and checked to make sure it runs smoothly on fresh diesel. From there, you're ready to pull away. There's no need to go to a garage at any stage, since the work is all done where the car is, and when it's caught soon, lasting damage is very unusual. ## A different matter: AdBlue in a diesel tank around Portaferry The problem isn't the same, though the first instruction is — don't fire it up — if what got in was AdBlue rather than petrol. Petrol does two things to diesel: dilutes it, and takes away the protection your fuel system depends on. AdBlue is urea in water, and in a diesel tank it leads to corrosion and residue instead. AdBlue removal in Portaferry has a page of its own with the detail on it, including why it's usually the more significant of the two. Our technicians handle both. Hire car or company car? Phone them before you ring us — some contracts want the hire firm to sign off the work, and sorting that out first is a great deal faster than sorting it afterwards. Then call us about the Ford Focus close to a street just off the centre, and don't worry that you can't say how full that tank was. Almost no one can, in a car they collected two days ago, and we work it out on site. The reason our engineers ask is that petrol in a diesel does its damage as a share: the same few litres in a nearly empty tank is a far stronger blend than in a full one. Petrol is rated on how well it resists igniting under pressure, which is the opposite of what a diesel needs — so the stronger the mix, the more it rattles, smokes and goes flat. ## What a petrol-in-diesel fuel drain will cost around Portaferry Truthfully, no single price belongs on a page like this. This job varies. Here's what varies it: - Whether the engine has been run or driven. This is the main one. - How much of the wrong fuel went in, measured against how much the tank can hold. - The type of fluid in the tank, petrol or AdBlue. - Access: the car's position, and if working on it there's safe for our van. A clear answer instead of a range is what you get for telling us three things: the vehicle, the quantity, and whether it has run. For the vehicle at home that's going nowhere and is not pressing, is fine too. That softness is the fuel failing to build pressure fully, not the engine packing up — and with no dashboard light for it, motors in that position typically get driven a second time before somebody phones. Please don't. A couple of streets is all it got: throttle gone dead, idle turned uneven, and a diesel Mercedes C-Class now sitting by the far end of the built-up part. Turn it off then phone us. ## Petrol in diesel queries from Portaferry motorists ## At a petrol station around Portaferry, can you do a fuel drain there? A good share of this work takes place there, so yes. Consent from the site is the condition. Given that, a forecourt like another forecourt nearby is somewhere we're frequently, along with the rest of them locally — so name yours on the call and you will hear whether working there's possible. ## How much petrol is too much for a diesel? It depends on the proportion instead of the litres, and much more on whether your engine has run. Five litres in an almost empty tank is a distinct matter from five in a full one — but either way, the thing that decides how much work is required is if that blend has been pulled through the system. ## Already driven it with petrol in the diesel? What now? Somewhere sensible, then stop, then turn off and keep it off. It's salvageable much more often than motorists expect, even though driving is what moves the problem from the tank into the pump and injectors — and the single most valuable thing you can do now is not restart it. ## My warranty — does a fuel drain void it? A manufacturer's warranty withstands a drain then flush done to a correct standard, which is no alteration at all. Running a diesel on petrol is the thing more likely to cause a dispute with one, which is another reason to leave it turned off. ## Can I just add two-stroke oil and drive home? Two-stroke oil solves a different issue, and an old one at that. Nothing it does puts back what petrol diluted. No. Petrol remains in that tank later on, whatever else goes in, and your pump gets no reprieve from it. ## Main dealers and petrol in a diesel There is no need to bring it to a dealership, because we drain and clean your car wherever it is. ## You, and your vehicle, still together? Leave the engine shut off. Switch it off somewhere safe and keep it off, if you have already driven it. A parked, cold motor is the best position to be in, and this is recoverable from much more commonly than motorists fear. Call-out fuel draining around Portaferry and throughout County Down — at the roadside, on the forecourt or at home.