How Worried Should You Be? Petrol in a Diesel Car in Tremar
Likely less than you are now — as long as no one has started it. Everyone around Tremar starts with "have I ruined it?", and the honest answer is usually no: petrol resting inside that tank of any diesel remains harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to phone, with your engine kept off, and so it stays that way. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and ways to make sure you never repeat it.
Petrol in a diesel: what does it do to the motor?
On its way through a motor, diesel does two jobs. Before it combusts, it protects — then it ignites. The high-pressure fuel pump and the injectors are built to very fine tolerances, and your diesel passing through them is what stops those surfaces from grinding against each other.
The second task petrol doesn't do at all, and the first it does badly. It is runnier than diesel and strips away the lubrication the system rests on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Taken together, they make clear the shape the issue has. It's circulation that does the harm, not contact. Petrol in a tank is a fuel problem. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors beyond it.
Tremar, petrol in a diesel: four cases, from mild to significant
Filled up, and never started: no case is better. On a forecourt, and really only there, that petrol is still confined to that tank — because everywhere else the vehicle was driven to reach it. The job is draining and cleaning on the spot.
Started for a moment, or just the ignition on. The fuel system has been primed, so petrol has left the tank and reached the fuel filter and the lines. Normally little more than draining, rinsing and sorting your filter, and so still simple.
A couple of miles driven, and your pump has spent each of them running on diluted fuel. Tank, lines, filter, then clean fuel put through the entire circuit: that is this work, and the way your car was driven matters as much as the distance. Driving the kids to St Cleer Primary Academy is one kind of trip. Any miles on the M5, under 50 miles from Tremar, means your engine working hard throughout, and a run to Plymouth, under 25 miles away, is a very different job too.
Rattling, an uneven idle, smoke, a throttle gone soft: driven until it complained. That's your engine telling you its fuel no longer is behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Kimberley Lane. What goes first is still the drain and flush-through, and that sorts it out, with permanent damage very unusual if a vehicle is stopped early.
Tremar motorists and that petrol in a diesel stories they hear
False: topping up to full with diesel makes it fine. It doesn't. A bigger tank of the same mixture is all you get, because topping up takes out nothing. Percentage is not how a diesel fuel system tolerates petrol, whatever that advice presumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. Finer parts and higher pressure are the way a modern diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, so no harm done" — the myth that trips up most drivers than any other. The motorist of a petrol motor fed diesel normally has no choice but to stop, because it will not run, and the harm stops there. Whilst the pump wears, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Being able to run isn't proof of being fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, meant for another issue. None of what petrol thinned gets put back by it — and later, that tank still contains that petrol.
The next start sends petrol back round your pump from the lines and the filter, where some of it ends up after your engine has been run. That is why draining your tank yourself doesn't sort it — a myth. It's also truly hazardous to drain petrol into a can by the roadside.
Petrol in a diesel: how does it take place?
Nobody does it on purpose, and it's rarely carelessness. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol motor at all. So the mistake runs one way.
Habit and the car falling out of step is how it happens. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Filling up in a rush on the way to Liskeard, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: precisely when it takes place. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up in Tremar: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the pump's label; the colour is just a hint.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before the first fill: many vehicles state the fuel type there.
- One of each in the home? Mark your key to your diesel — a coloured fob, a sticker — since intending to remember isn't enough.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. It sounds silly and it works.
- Mistakes like this are straightforward to make whilst your mind is on something else, so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and add-on devices are available for the remainder. Count it as a safety net, then keep checking the petrol pump.
- The moment you realise, stop: less petrol inside that tank means a thinner blend. What to do next does not change, though — still do not fire it up.
Petrol already in a diesel around Tremar? Begin here
The order of things is brief, then. Don't switch the ignition on, and do not crank it. Ask the staff to help you roll it away from the petrol pump if you're still at the forecourt, whether that is BP or anywhere else. Phone 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it's run.
If it was AdBlue rather than petrol, say so. That's a different problem — corrosion and deposits rather than lost protection — and it has its own page for Tremar.
Tremar petrol in a diesel tasks: why one costs more than another
Four separate jobs lie behind the four situations above — which is why there's no honest single quote. What moves the cost is chiefly which of them you are in. Two things follow that: the petrol that got in as a share of what that tank takes, then the spot the car is in and whether a van can reach it safely.
Three questions come first, before quoting, rather than after — what got in, how much, has it run — and that is the reason. Given those answers, there is a straight figure rather than a range.
About Tremar and where it is
Tremar is a small village in Cornwall, situated inland at an elevation of 147 metres. Tremar lies near several other settlements, including Lower Tremar and Tremar Coombe, and is close to the Rosecraddoc area. Tremar has a population of around 548 people, predominantly living in detached houses. Tremar is located approximately 16 miles from Plymouth and 201 miles from London.
Fuel drain cover across Cornwall, Tremar included
Petrol in diesel call-outs in Tremar — part of the PL postcode area — go to teams that also cover the spots round it, Lower Tremar, Tremar Coombe and Rosecraddoc included. We drain where the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the petrol pump in Tremar?
The best place there is, then — that's where you are. Switched off it remains; then ring.