Great Shelford: Put Petrol in a Diesel Car?
With your tank still carrying the petrol and your engine not yet turned over, nearly every job takes only a drain, so leave the motor off. That result is decided in the minutes straight after filling up, and not by the amount that got in. Across Great Shelford and the rest of Cambridgeshire, Petrol in Diesel drains your car and flushes it where it stands, whether at a roadside, on a private drive or at a forecourt. Contact us and then our technicians can show you what comes from here before you do anything else.
Your first five steps: petrol in a diesel
- Don't start the vehicle — and do not rely on it when it fires up. Here is the part drivers get wrong about petrol in a diesel specifically. A petrol engine fed diesel usually just can't run, and so the driver stops and the damage halts with them. A diesel given petrol usually starts, idles and pulls away quite happily for a few miles. It isn't all right. It is grinding the fuel system whenever you drive.
- Switching the car's ignition on often primes that system, and priming is what draws petrol out of the tank and into the pump and injectors. Those are the parts diesel keeps greased on its way through, before it combusts. Petrol handles the burning and none of the protecting. Leave your ignition alone.
- Do not dilute it. Diesel tipped on top removes nothing, so all you have is more of what was already there, since percentage isn't how a diesel fuel system copes with petrol. Super unleaded? Still petrol. The type makes no difference.
- Stay put if it's sensible to. Hazards on, ignition off, keep the car. Wherever you have stopped — the verge on Tunwells Lane, anywhere — an odd spot for us beats a started engine, and nothing is easier for us to sort out than a vehicle that never moved.
- Keep your location prepared before you phone. A postcode starting CB22 5 and whatever is next to you with a label on it is the difference between the van turning up and a van circling.
- What was put in, roughly how many litres, plus if the car has run — the three replies shape the entire job. Phone 0333 366 0103 and tell us.
Can petrol be pumped from your diesel at a forecourt?
Much of the work starts at a pump, so a good part of it ends up finished at one. If you're still on the forecourt at Esso, that's usually where the drain happens — our technicians work on station forecourts regularly, with the owner's agreement.
No place except a garage can this be spotted with the motor still unstarted. Fuel pulled out of your tank and through the fuel filter, all the way to the high-pressure pump, is what occurs when your engine is fired up and your car is driven to where it is now: the car park, the driveway or the lay-by, everywhere other than the forecourt. So the flush takes in the fuel filter and the fuel lines along with that tank. That's still not a catastrophe, and we put it right where the car sits. What settles it is whether the key was turned in the seconds after the receipt was read.
The attendants will generally happily roll it out from the pump so the next customer can get past. That is worth doing. Cranking it over four car lengths? Don't.
Car parks like the one outside Co-op Food are a spot our engineers work in all the time, and the fuel is seldom the complicated part. The bay is: motors either side, a trolley shelter behind, sometimes a height bar on the way in that determines if our van can reach you at all. So tell us how hemmed in you are when you call, and which way the vehicle is facing. If our engineers can't work beside your diesel Renault Megane we'll shift the car without firing it — and that isn't pedantry about a couple of seconds of running. Each start primes the fuel system and pulls more of that mix out of your tank and on to the pump, so a car shunted twice into a better bay has silently become a worse job than one left just where it stopped.
Twenty to nine outside Great and Little Shelford CofE (Aided) Primary School, running late, and your receipt in your hand reads unleaded. Hazards on, engine off, ring us. Three miles in the Skoda Octavia sounds like nothing, but a diesel pump supplies fuel to demand — and a hurried morning drive demands plenty.
Diesel has to be heavy enough to seal the precision parts it flows through, and petrol dilutes it. That is the full mechanism, and it accounts for the ordinary Villedomer Garden call: a diesel Nissan Qashqai that drove out there without complaint and came back down on power, rough at idle, possibly smoking a little. A diesel injection system works hydraulically as well as chemically — it requires your fuel to hold pressure, not merely to burn — so when the fuel weakens, pressure that should build then stay built starts escaping past tolerances instead, and the engine gets a weaker, later, less even delivery than it was built about. No part of that is your engine failing, which is the bit worth hearing: it's your fuel no longer behaving like diesel, and it stops when your fuel is put right.
Emptying the Mercedes C-Class, changing your filter where there's a workable one, purging your lines, putting fresh fuel through the whole system: that is the job, and it is shaped by the worst of that resting in the lines rather than in your tank by this point. Three things help when you phone from close to Shelford Free Baptist Church — which side the filler is on, whether our van can stand beside without blocking the road, and whether your engine has run since you filled up. On-street is the commonest spot our engineers work, and so the place itself is rarely the trouble. A tight parking bay trumps a car driven somewhere more convenient.
By this point your tank is not where most of the trouble is. Once a diesel has run, the blend is in the filter, the fuel lines, the pump and its rail — and it doesn't come back out with your tank contents. A diesel Kia Sportage that got near Memorial Hall needs your system flushed, not emptied.
Service around Great Shelford
Those same rounds take us to Freestones Corner, Stapleford, Little Shelford, Hauxton and Trumpington along with Great Shelford, which is a village.
Not on this list? It says nothing. The places above are only the closest few, and nearly all locations across Cambridgeshire have a page of their own elsewhere on our site. Ring us to check rather than guessing — borders especially, and wherever your satnav may misread.
That map outlines the ground this page includes. The lot is ground our engineers work: a roadside, a forecourt, a private drive, a car park. You do not drive the car anywhere.
Stopped on the roadside somewhere in Great Shelford?
Not everybody gets a decent place to pull in. Hazards on in a lay-by somewhere, or pulled onto the verge of High Street as you worked it out after setting off — our technicians take that call regularly enough that it is the normal kind.
Whether you sit beside the car or move away from it rests on if being there is wise. It will often oblige. A diesel running on petrol limps along perfectly willingly, and that's the trouble: restart the vehicle to get to somewhere safer and that mix goes further into the fuel system with every mile covered. However difficult the location, it is no problem for us to come to it, and that's far better for your car than driving on.
Petrol in a diesel, and the vehicle has travelled
Here is where your M11 counts, under 3 miles from Great Shelford. A loss of power, a rough idle, some smoke: those are the signs when they arrive, instead of a neat stop — and a misfuelled diesel will often take you onto it and some distance along before anything seems wrong at all.
Pull off at the next safe exit, turn off, and never restart it to reposition. Assume the worst of it on a long trip. Anything close to the under 5 miles to the closest city, and the mixture has been through the filter, through your pump, through the fuel injectors. Say so when you phone. What we bring alters.
About Great Shelford
Great Shelford is a village situated on the River Cam in Cambridgeshire, with a low elevation of around 19 metres. Great Shelford lies close to the city of Cambridge, approximately 3.8 miles to the south, and is part of the wider Cambridge urban area. Great Shelford has a mix of housing types, but semi-detached homes are particularly prevalent in the village. Great Shelford is also near to other small settlements, including Freestones Corner, Stapleford, and Little Shelford.
What comes next when our technicians get to you around Great Shelford
- The replies shape the work, which is why our engineers ask before quoting: what was put in, how much of that, and whether the motor has run.
- The tainted fuel is pulled out of that tank.
- Fuel lines are cleaned through and your filter cleaned, leaving nothing in your system that caused any of this.
- Priming follows, once clean diesel is in.
- Once it is turned on, our engineers check it runs smoothly on clean diesel.
The vehicle is then ready for you to drive away. Our technicians do all of this wherever the car has ended up, which means it never needs to be taken to a garage, and when it has been spotted soon, it is very rare for there to be permanent damage.
AdBlue in a diesel tank in Great Shelford is a different problem
Never crank it: that opening instruction holds whether what went in was AdBlue or petrol. What differs is the fault itself. Petrol thins your diesel and takes away the protection the system depends on. Rust and deposits are what a diesel tank gets instead, as AdBlue is urea dissolved in water.
Both are ours. There's a separate Great Shelford page for AdBlue removal, with the full story on it — including the reasons it frequently turns out to be the worse of the two.
Paying for a petrol-in-diesel fuel drain in Great Shelford
What shifts the figure is set out below, as this job is not one job and our technicians cannot truthfully put a single number on this page.
- Whether your engine has been run or driven. This is the key one.
- The tank's capacity, set against how much of the wrong fuel got into it.
- Whether it's unleaded or AdBlue.
- Where is it? And can a technician get to it and work there safely?
Tell us what the car is, how much went in, and whether the motor has run. A firm answer comes back, not a range. Not urgent, with the car at home and going nowhere? Then is fine.
Petrol in diesel: common queries around Great Shelford
At a petrol station around Great Shelford, can you do a fuel drain there?
A large share of this work gets done there, so yes. Regularly, provided the site agrees: Shell, plus every other forecourt nearby. Say on the phone where precisely you have stopped. Whether our engineers can work in that spot is something we answer on the spot.
A few litres of petrol in a diesel — too much?
Ratio decides it instead of litres — and more than either, whether your engine has run. A nearly empty tank with five litres in it, against a full one with the same five: different scenarios, certainly. Either way, the work required comes down to one thing, which is if the fuel system has had that blend sucked through it.
I drove the vehicle after putting petrol in my diesel. What next?
Switch off somewhere sensible, then keep it that way after you stop. It is fixable much more regularly than motorists expect, even though driving is what moves the trouble from that tank into your pump and injectors — and the single most useful thing you can do now isn't restart it.
My warranty — does a fuel drain void it?
A manufacturer's warranty outlasts a drain and flush done to a correct standard, which is no change at all. Running a diesel on petrol is the thing more likely to cause a disagreement with one, which is another reason to leave the vehicle switched off.
Could I put some two-stroke in and just drive?
What petrol has diluted is not put back by two-stroke oil, which is an old workaround for a distinct problem. So no. The pump still has to cope with it, because the tank still has petrol in it after that.
Main dealers and petrol in a diesel
There is no need to take it to a main dealer, because our engineers drain and flush your car wherever it is.
Still with the vehicle?
Turned off is how it remains.
Switch it off somewhere sensible then keep it off, if you have already driven it. Cold, parked, going nowhere: that's the best position to be in. Drivers fear this much more than they need to.
Throughout Cambridgeshire and around Great Shelford: mobile fuel draining, at home or on the forecourt or at the roadside.