Should You Worry? Petrol in a Diesel Car in Bryncoch
Probably less than you already are — as long as no one has started the vehicle. Until your ignition primes the pump, the starter cranks, or the car is driven, petrol in a diesel tank simply sits there and does no harm. Which means the honest reply to the first Bryncoch question — "have I ruined it?" — normally no. Leave the engine off then call Petrol in Diesel — that is how you keep it like that. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that's the remainder of this page.
Inside the engine: what petrol in a diesel really does
On its way through a motor, diesel has two jobs. Before it ignites, it lubricates — and then it burns. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing down against one another is your diesel passing through them — they're designed to extremely fine clearances.
The second job petrol doesn't do at all, and the first it does badly. The rattling comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system depends on, and any pump working on that mixture is wearing itself.
Seen together, they make clear the shape the trouble has. The damage is done by movement, not by contact. Where the petrol is only in that tank, it is an issue of fuel, nothing more. After your pump has been labouring on that petrol, a mechanical fault has started: anything shed by a pump that is grinding is carried downstream to the fuel injectors with your fuel.
Bryncoch, petrol in a diesel: four situations, from mild to major
Filled up, and never started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With the petrol kept inside your tank alone, it's drained and purged right where it stands, and nothing more is needed.
A brief spell of running, or just the ignition on. Petrol has left that tank and got to the filter and the fuel lines, because your system has been primed. Drain, flush, see to your filter: still usually easy.
Some miles driven, and the pump has spent every one of them running on diluted fuel. How hard your car was driven counts as much as how far, and this work covers that tank, the lines, the filter and fresh fuel through the whole system. The school run to the local primary school is one matter. Very different a second time: a trip to Swansea, under 25 miles away, or any distance on the M4, under a mile from Bryncoch, where the motor never stopped running hard.
Rattling, an uneven idle, smoke, a throttle gone soft: driven until it complained. That's the motor telling you its fuel has stopped behaving like diesel. Pull up where you are — on the verge on Laurel Close, at the kerb, down a side road — and do not move it. What comes first is still the drain and flush-through, and that takes care of it, with long-term damage very rare when a car is stopped quickly.
What Bryncoch motorists get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing comes out when you top up — that tank just carries more of the same blend. Percentage is not how a diesel fuel system copes with petrol, whatever that guidance presumes.
Myth: a current diesel copes with a bit of petrol. If anything, the opposite. A modern diesel sends its fuel through more precise components at higher pressure, which makes the lubrication count more, not less.
This is the one that fools people. Myth: "If it starts and drives, there is no damage done." Feed diesel to a petrol engine and it generally will not run, so the motorist stops — and the damage stops with them. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, while the pump grinds. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive the car home." It's an outdated workaround for a separate issue. None of what petrol thinned is put back by it — and afterwards, the tank still holds that petrol.
If the motor has run, part of the petrol sits in the fuel filter and your lines, not that tank — and the next start pulls it right back through the pump. So the myth "drain the tank yourself and you're sorted" doesn't stand up. Besides, petrol drained into a can by the road is genuinely risky.
Why petrol in a diesel takes place so easily
A careless moment is rarely the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error straightforward, and only in one direction.
Habit and the car falling out of step is when it occurs. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the drive. A forecourt you know, only with its pumps laid out differently. A train to catch, and a hurried fill on the way to Sarn. A new-to-you diesel Renault Clio, its first fuelling, and a motorist accustomed to petrol: exactly when it occurs. Add a back seat full of children, a phone call or rain, and the hand takes over.
How to avoid petrol in a diesel at your next fill-up around Bryncoch
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on every forecourt. The label is what counts.
- In a car you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of motors print the fuel type there.
- Label the key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- It sounds daft 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.
- Put your phone away. This is an easy mistake to make while you are thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a thinner blend, and so stop the moment you notice — though remembering that the next step is unchanged. It's still not to crank it.
Bryncoch: already put petrol in a diesel?
Then, there is only a short order of things. Do not switch the ignition on, and do not fire it up. Ask the attendants to help you push it away from the petrol pump if you're still at the forecourt, whether that is Welcome Break or somewhere else. Next, 0333 366 0103. We will ask what went in, roughly how much, and if it has been run.
If it was AdBlue instead of petrol, say so. That is a separate problem — corrosion and deposits instead of lost lubrication — and it has its own page for Bryncoch.
What makes one Bryncoch petrol in a diesel task cost more than the next
The four scenarios above are four different jobs, so no single price for this would be honest. What moves your cost is chiefly which of them you are in. The ratio counts next, meaning how much of the tank is petrol, followed by the position of your car and whether getting to it is safe for our van.
What was put in, how much, and if it has run — three queries our technicians ask before pricing, not after, for exactly that reason. With the replies, you get a straight figure rather than a range.
About Bryncoch, for a moment
Bryncoch is a suburban area in Bridgend, situated on the riverside at an elevation of around 75 metres. Bryncoch lies near the communities of Cymdda, Bryncethin, and Sarn, and is approximately 16.7 miles from Swansea. Bryncoch has a population of around 3282 people, predominantly living in semi-detached housing. Bryncoch is located in a region with easy access to major cities, being around 148 miles from London.
Across Bridgend and in Bryncoch: fuel drain cover
Cymdda, Bryncethin and Sarn are among the spots near Bryncoch that the same vans work, answering petrol in diesel jobs across Bryncoch's CF postcode area. The car doesn't need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Bryncoch, still?
Then you're in the best position there can be. Keep the vehicle turned off, then ring.