Stevenage: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — provided no one has started the car. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the fuel system — the ignition priming your pump, the starter, or the drive on its own. So the fair answer to the first query everyone around Stevenage asks, "have I wrecked it?", is generally no. Keep it like that: leave your motor off then ring Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you don't repeat it.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel does two jobs at the same time. Before it burns, it protects — and then it ignites. What stops the surfaces inside the high-pressure fuel pump and the injectors from wearing against one another is the diesel flowing through them — they're made to very fine clearances.
Of these two tasks, petrol manages the first badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on the mixture to wear itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the clattering.
Put those together and the shape of the trouble is plain. It is movement that causes the damage, not contact. A tank with petrol in it is a fuel problem. Whatever a worn pump sheds travels on, carried by the fuel, into the injectors downstream, which is why a pump that has worked on that petrol is where a mechanical issue begins.
Four scenarios we see around Stevenage: how serious is petrol in a diesel?
The best case there is: filled up, never started. The petrol is in the tank and only that tank, and the job is a drain and a flush where the vehicle stands. This is the one situation that can only really happen at a forecourt, since anywhere else your car has been driven to get there.
Ignition on, or started for a moment. Once primed, your system has pulled petrol from that tank up to your filter and your lines. Usually nothing more than draining, purging and sorting the fuel filter, and so still straightforward.
The pump has worked a few miles on thinned fuel — that's what driving it does. Mileage is only half of that; how hard it was driven matters equally. Either way the work runs to the tank, your lines, your filter and clean fuel through the whole system. Short trips, like the school run to Broom Barns Primary School, are one thing. Very different a second time: a trip to St Albans, under 15 miles away, or some distance on the A1(M), under a mile from Stevenage, where the engine never stopped running hard.
Driven on till it protested — knocking, smoke, an uneven idle, a dead throttle. That is the motor telling you its fuel has stopped behaving like diesel. Stop where you are — on the verge on Park Place, at the kerb, down a side road — and do not move it. What comes first is still the fuel drain and flush, and that deals with it, with lasting damage very uncommon when a vehicle is stopped early.
Petrol in a diesel myths Stevenage drivers hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — the tank simply carries more of the same blend. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. At higher pressure, through finer parts: that is how a modern diesel handles its fuel, so the lubrication counts for more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches people. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump wears. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old workaround for a different issue. It doesn't put back what petrol has diluted, and that petrol is still inside the tank afterwards.
Myth: "Drain your tank yourself and you're sorted." Once the engine has run, some of that petrol is no longer inside your tank: it is in the fuel filter and your lines, and it goes straight back through your pump at the next start. Emptying petrol into a can by the kerbside is also really dangerous.
Why petrol in a diesel occurs so easily
On purpose? Never. Through carelessness? Rarely, if ever. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol car. That's how the forecourt makes it easy.
The moment routine stops matching your car is the moment it takes place. Courtesy car, hire car, or a motor that's brand new. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. Rushing for a train outside the nearest station and fuelling up en route. Years of petrol vehicles behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. Add a back seat full of children, a phone call or rain, and habit wins.
Avoiding petrol in a diesel next time you fill up in Stevenage
- Green for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- Inspect your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in a vehicle you don't know.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key if a home has one of each. So mark it.
- It sounds silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Tuck your phone away. This is an easy mistake to make while you are thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for the rest. Treat it as a safety net, then keep checking the pump.
- Spotting it halfway? Stop at once. A weaker mix follows from less petrol in your tank, but the next stage remains the same: don't fire it up.
Put petrol in a diesel around Stevenage already?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off as well. The staff on the forecourt — whether at Tesco itself or wherever you filled up — will normally help push it clear of the pump if you ask. Phone 0333 366 0103 next, with three facts — the fuel, the rough amount, and if it has run.
Corrosion and deposits form the trouble with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Stevenage page.
What makes one Stevenage petrol in a diesel job cost more than the next
There's no fair single price for this, because the four scenarios above are four different jobs. What shifts your cost is chiefly which of them you're in. The proportion matters next, meaning how much of your tank is petrol, and then the location of your car and whether getting to it is safe for our van.
What got in, how much, and if it has run — three queries our engineers ask before pricing, not after, for exactly that reason. Given those answers, there is a straight figure rather than a range.
About Stevenage, briefly
Stevenage is a town in Hertfordshire, situated on the banks of the River Lea, with a mix of old and new buildings, including the historic Old Town area. Stevenage sits at an elevation of around 94 metres, approximately 27.5 miles north of London, and is surrounded by nearby places such as Bedwell and Pin Green. Stevenage has a population of around 20631 people, predominantly living in terraced housing. Stevenage is also close to the city of St Albans, which is about 11.9 miles away.
Fuel drain cover across Hertfordshire, Stevenage included
The teams answering petrol in diesel calls in Stevenage, in the SG postcode area, equally work the spots near it, Bedwell, Old Town and Pin Green included. The car doesn't need to come to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the pump in Stevenage?
Then you are in the best position there is. Leave it turned off, and ring.