Tyn-y-garn: Petrol in a Diesel Car? How Worried to Be
If it hasn't been started, you can worry less than you likely are. Petrol resting in a diesel tank does nothing to the motor till something draws it through your fuel system — your ignition priming your pump, your starter, or the drive itself. So the honest answer to the first query anyone in Tyn-y-garn asks, "have I ruined it?", is normally no. To keep the vehicle that way, phone Petrol in Diesel and leave your engine alone. Further down, you will find what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
Your engine and petrol in a diesel: what happens
On its way through a motor, diesel does two tasks. Lubricating comes before burning; it does both. The high-pressure fuel pump and the injectors are designed to very fine gaps, and the diesel passing through them is what keeps those surfaces from wearing down against one another.
Poorly at the first, not at all at the second: that is petrol. The knocking comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication your system rests on, and any pump working on such a blend is wearing itself.
Put these together and the shape of the issue is clear. Contact does not do the harm — circulation does. Petrol in a tank is a fuel fault. Whatever a worn pump sheds travels on, carried by the fuel, into the fuel injectors further along, which is why a pump that has been working on the petrol is where a mechanical fault begins.
Four scenarios our technicians see in Tyn-y-garn: how serious is petrol in a diesel?
Fuelled but not once started — as good as it gets. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With the petrol held inside the tank alone, it's drained and cleaned right where it stands, and nothing more is needed.
A moment's running, or merely the ignition on. Your system has been primed, so petrol has left the tank and got to your filter and your lines. Still usually easy: drain, flush, and the fuel filter sorted.
Driven a few miles. Now the pump has spent these miles running on weakened fuel. How hard the car was driven matters as much as how far, and the work covers that tank, the lines, your filter and clean fuel through the entire circuit. Driving the kids to the local primary school is one sort of trip. Driving as far as Swansea, under 25 miles away, makes a very different task — as does any distance on the M4, under a mile from Tyn-y-garn, with your engine working hard the whole time.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone ragged. That's the engine telling you its fuel has stopped behaving like diesel. Stop where you are — on the verge on Graham Avenue, at the kerb, down a side road — and do not move it. Lasting damage is very uncommon if a vehicle is pulled over early, and the drain and flush that still come first take care of it.
Tyn-y-garn people and that petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A bigger tank of the same mixture is all it gives, since topping up removes nothing. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. Protection matters more on modern diesels, not less, because their fuel passes through finer parts at higher pressure.
"It starts, it drives, and so no harm done" — the myth that trips up more motorists than any other. Diesel in a petrol motor usually means a motor that will not run: the driver stops, and so does the damage. Feed petrol to a diesel and it usually fires up, idles and pulls away as if nothing has happened — all while its pump wears. Fine and running aren't the same thing.
An outdated fix for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol weakened gets put back by it — and afterwards, your tank still contains the petrol.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in the fuel filter and lines, waiting to go right back through your pump on the next start. It is also truly dangerous to drain petrol into a can by the roadside.
Petrol in a diesel: how does it happen?
Nobody does it on purpose, and it is seldom carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it easy, and the mistake runs one way.
It takes place when habit and the car stop matching. Courtesy car, hire car, or a vehicle that's new. Two motors on one driveway, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill en route to Sarn. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Next time you fill up around Tyn-y-garn: avoiding petrol in a diesel
- The label is what matters, and so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- The first fill in an unfamiliar motor is the time to check the filler flap — on it, or on the cap, many vehicles state the fuel to use.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So mark it.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- While you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that won't accept a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- As soon as you realise, stop: less petrol inside that tank makes a weaker mixture. What to do next does not change, though — still don't start the car.
Put petrol in a diesel in Tyn-y-garn already?
Short and simple, then, is the order of things. Leave it unstarted, with your ignition switched off as well. Yet on the forecourt, at Murco or anywhere else? Ask the attendants to help you push it clear of the petrol pump. Ring 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it has run.
If it was AdBlue instead of petrol, say so. That is a different issue — corrosion and deposits and not lost lubrication — and it has its own page for Tyn-y-garn.
What makes one Tyn-y-garn petrol in a diesel task cost more than the next
The four scenarios above are four separate jobs, so no single quote for this would be honest. Chiefly, your cost moves with which situation you're in. The share matters next, meaning how much of your tank is petrol, followed by the position of the car and whether reaching it is safe for a technician.
That is why our technicians ask three questions before costing instead of after: what was put in, how much, and whether it has run. Those replies change a range into a straight figure.
About Tyn-y-garn itself
Tyn-y-garn is a locality situated in a riverside setting in Bridgend, with an elevation of 69 metres above sea level. Tyn-y-garn is located near several nearby places, including Pen-y-fai, Pen-y-cae, and Aberkenfig, and is approximately 16 miles from the city of Swansea. Tyn-y-garn has a population of around 1516 people and is characterised by predominantly detached housing. Tyn-y-garn is also within commuting distance of major cities, being around 149 miles from London.
Fuel drain cover across Bridgend, Tyn-y-garn included
Our vans answering petrol in diesel jobs in Tyn-y-garn, in the CF postcode area, equally work the spots around it, Pen-y-fai, Pen-y-cae and Aberkenfig included. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations we drain, and your car doesn't need to come to us.
In Tyn-y-garn and still at the petrol pump?
Then you're in the best spot there is. Keep it off. Call.