Put Petrol in a Diesel Car in Foxhole? Don't Start It
Petrol in Diesel drains and flushes wrong-fuelled cars where they are, on the forecourt, by the roadside or on a private drive, all over Foxhole and the rest of Swansea. The first thing to do is not to turn on your engine. While the engine has not yet been started and the petrol is still inside the tank, a tank drain is almost always all it takes, and the following few minutes decide that, not how much got in. A single ring to us will be plenty: we will show you what comes next. Do that right away.
What next? Petrol in a diesel, in turn
- Feed a petrol engine diesel and it will normally not run at all, and so the driver stops there and so does the damage. Give a diesel petrol and the engine starts, it ticks over, it drives off — all right for several miles. Most people have that reversed, which is the thing they get wrong about petrol in a diesel especially. So never fire it up. And once started, don't rely on it: your fuel system is grinding whenever you drive.
- Diesel ignites, and before it ignites it lubricates — the high-pressure fuel pump, its injectors. Petrol handles only the burning. So leave the ignition be also: flicking it on is commonly all it takes to prime your system, and priming draws petrol from your tank into exactly those components.
- That guidance assumes a diesel fuel system handles petrol by percentage. It will not. Tip diesel on top and nothing at all is taken out; what you get is a larger tank of the same mixture. And no, the type makes no difference — super unleaded is just petrol.
- A vehicle that has not moved is the quickest one to deal with, so wait where you are if you sensibly can. Pulled up on the verge on Deepglade Close? Hazards on, and leave the vehicle there. A tricky location works for us better than a started engine.
- Keep your position ready before you call. A postcode starting SA1 8 and whatever is next to you with a sign on it is the difference between the van arriving and the van circling.
- What got in, roughly how many litres, plus if your car has run — the three facts shape the whole visit. Call 0333 366 0103 and tell us.
Quarter past eight, a fast fill-up on the road in, and the penny drops around eleven — by that point your diesel Renault Megane has been sitting outside Swansea for three hours. Ring us then keep the vehicle precisely where it stands. The journey in is the part that counts here, since diesel has two tasks on its way through the engine: it combusts, and before it burns it protects the high-pressure fuel pump and the injectors. Petrol does the first and not the second. So those couple of miles were done with your pump labouring on a fluid that had lost most of the protection it is designed around — which is why the thing our engineers ask is how many miles you drove, not how long the vehicle has been standing.
Every start primes your fuel system and pulls more of that mix out of your tank and toward your pump — which is why a vehicle shunted twice into a roomier spot has quietly turned into a bigger job than one left just where it stopped. So if our technicians can't work alongside your diesel Volkswagen Tiguan, our technicians roll the vehicle without firing it. None of that is fuss about a couple of seconds of running. Car parks like the one outside CK's our engineers visit regularly, and the fuel is seldom the tricky part: the bay is. Vehicles either side, a trolley shelter behind, occasionally a height limit at the entrance deciding if a technician can reach you at all. Tell us how boxed in you are, and which way your car faces.
Every restart primes the lines and draws more petrol past the fuel filter then into the pump. So a misfilled diesel Nissan Qashqai on the zig-zags outside the local primary school is a hassle, whereas the same motor fired up three more times to be courteous is a fuel system rather than a tank. A passer-by will advise you to move it out of that gateway and sort it out later. Don't. Leave it there, let everyone grumble, then phone us.
None of it is the engine failing. That is the bit worth hearing, and it is why the usual Kilvey Community Woodland call ends better than it sounds: a diesel Ford Focus drives out there without a murmur, comes back with the power gone, your idle lumpy and possibly a little smoke, and the cause is your fuel no longer acting like diesel. Diesel has to be thick enough to seal the close-fitting parts it passes through; petrol dilutes it; and a diesel injection system is hydraulic as much as chemical, needing your fuel to hold pressure instead of only to burn. So pressure that should build then stay built leaks past tolerances, delivery arrives poorer and later and less even than designed, and all of that stops once your fuel is sorted.
Three things help when you ring from close to Saint Thomas Community Centre: which side the filler is on, whether our van can stand alongside without blocking the road, and whether your engine has run since you filled up. On-street is the commonest spot we work, and so the place itself is rarely the trouble — we would much rather deal with a narrow parking space than with a car that has been driven to somewhere more handy. We will drain your Mercedes C-Class, change the filter where there is a workable one, flush the lines and put fresh fuel through the whole system, as by this point the worst of it is sitting in the fuel lines instead of in your tank.
At the forecourt: draining petrol from a diesel
A fair part of the job gets completed at a pump, since that is where it mostly starts. The drain usually takes place right there. Still on the forecourt at Sainsbury's? Given the owner's agreement, that's a spot our technicians work, and often.
At the forecourt, this gets halted with your motor never run, and no place else manages that. Our engineers can still sort it out where it stands, even away from the pumps. In a car park, on a driveway or in a lay-by, the vehicle has been fired up and driven there, and that drew fuel through your filter then into your high-pressure pump, all the way from the tank. None of that is a disaster, although the flush then has to go past your tank to your lines and your filter, and the few seconds between seeing the receipt and going for the key are what settle that.
Roll it out of the way if the staff suggest it, and they normally will. The next customer gets past the petrol pump, and that is worth doing. Cranking the car for four vehicle lengths? Don't.
Areas our team reach around Foxhole
Foxhole is a residential suburb, and our team go out to it and to anywhere by it on those same journeys: St Thomas, Hafod, Dan-y-graig, Swansea and Pentre-chwyth.
If yours isn't on that list that does not mean we don't come — there are dedicated pages for nearly all places in Swansea, and the ones named above are merely the immediate neighbours. On a border, or anywhere the satnav struggles with? Contact us and check instead of guessing.
The ground the page includes sits on our map. All of it is territory our engineers serve: a kerbside, a forecourt, a drive, a car park. You do not drive your car anywhere.
Kerbside call-outs across Foxhole
A chance to pull over anywhere safe does not come to everybody. Hazards flashing in a lay-by somewhere, or stopped on the verge on Kilvey Road since you worked it out after setting off — we take that call often enough that it is the ordinary kind.
Whether you remain beside your car or move away from it depends on if being in it seems safe. Don't start up the engine to limp the car somewhere safer — a diesel running on petrol will usually oblige, and every mile it obliges for is dragging that mix further into your fuel system. Driving on does the car far more harm than a technician driving out to an inconvenient spot, and that is no problem for us.
Petrol in a diesel, and the vehicle has moved
under 5 miles out of Foxhole, your M4 is what counts here. It will frequently take you onto it, and some way along, before you notice a thing. Then it's smoke, an uneven idle and power ebbing away — not a tidy stop. Misfuelled diesels rarely give you one of those.
The next safe junction is the one to take. Turn off there, then leave the restarting alone. Long trip? Anything near the under a mile to the nearest city and you should assume the lot — filter, pump, injectors, all of it got to by the petrol. Say that on the call, because it alters what goes in the van.
About Foxhole
Foxhole is a suburban area in Swansea, situated near the coast and approximately 0.7 miles from the city centre. Foxhole sits at an elevation of around 57 metres, with terraced housing being the predominant type of accommodation in the area. Foxhole is close to nearby places such as St Thomas, Hafod, and Dan-y-graig, and is part of the wider Swansea urban area.
Once our technicians arrive with you in Foxhole: what happens
- Our engineers establish what was put in, how much, and if the engine has run. The replies alter the work, which is why our engineers ask before pricing.
- The tank gets cleared of everything.
- Fuel lines are flushed through and the fuel filter cleared, leaving nothing in your system that caused any of this.
- New diesel goes in, and then the fuel system gets primed.
- After it is started, our engineers make sure it runs smoothly on fresh diesel.
That has the car ready to set off. There's no need to go to a garage at any point, because the work is all done where the vehicle is, and when it is noticed early, permanent damage is very uncommon.
A distinct problem: AdBlue in a diesel tank in Foxhole
The issue isn't the same, though the first rule is — don't crank it — if what got in was AdBlue rather than petrol. Petrol does two things to diesel: dilutes it, and takes away the lubrication the fuel system depends on. AdBlue? Urea dissolved in water. Tip that in with the diesel and you get corrosion instead, plus build-up.
AdBlue removal around Foxhole has a page of its own with the full story on it, including why it is often the more significant of the two. We cover both.
What a petrol-in-diesel drain costs in Foxhole
Our engineers can't put one number on this page truthfully, because the job isn't one job. What changes it:
- Has it been run or driven? Nothing else counts for as much.
- How much of the wrong fuel went in, measured against how much the tank holds.
- Which was put in: petrol or AdBlue.
- Where is it? And can a technician reach it and work there safely?
The vehicle, the quantity, whether it has run — give us those and the answer comes back clear rather than as a range. Car at home, going nowhere, nothing time-critical about it — is fine for that.
Foxhole drivers ask us these about petrol in diesel
Fuel drains on a Foxhole petrol station forecourt
Much of what our engineers do takes place nowhere else. So yes. Permission from the site is the condition. Given that, a forecourt like Burrows Service Station is somewhere we're frequently, along with the rest of them locally — so name yours on the phone and you will hear if working there is possible.
A few litres of petrol in a diesel — too much?
Whether the motor has run matters far more, though the ratio matters too, instead of the litres. Five litres into a nearly dry tank is not five into a full one, no. But both land on the same question in the end: has that blend been pulled right through, or has it not?
I drove the car after putting petrol in my diesel. Now what?
Stop sensibly. Off. Nothing after that. Not restarting it is the single most valuable thing available to you now. Driving does move the problem out of your tank and into the pump and injectors, yes, and it remains recoverable far more frequently than drivers expect.
Is a fuel drain going to void my warranty?
A drain then flush carried out properly isn't a change and does not cancel a manufacturer's warranty. What's likelier to start an argument is a diesel that has been run on petrol. One more good reason for your engine to stay off.
Can I just add two-stroke oil and drive home?
No. It belongs to a different issue from a separate era, and petrol has weakened something no oil of that kind replaces. Petrol remains in that tank afterwards, whatever else goes in, and the pump gets no break from it.
A main dealer for petrol in a diesel — needed?
No. Our technicians drain and clean your car wherever it is, so there is no need to bring it to a dealership.
Still with your car?
Don't switch the car on again.
Switch it off somewhere safe then leave it off, if you have already driven it. Cold and stationary, a motor is in the best position available — and people fear this far more than the recovery rate warrants.
Mobile fuel draining in Foxhole and throughout Swansea — at the roadside, on the forecourt or at home.