Should You Worry? Petrol in a Diesel Car in Ayr
If it has not been started, worry less than you probably are. "Have I wrecked it?" is the first question everyone in Ayr asks, and the honest answer is generally no, since petrol resting in a diesel tank hurts nothing till it's dragged through your fuel system — by ignition priming, by the starter, or by driving. 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 clues of how far it has spread, and the way to make sure you don't do it again.
Petrol in a diesel: what does it do to your engine?
Diesel has two tasks on its way through a motor. Before it ignites, it lubricates — and then it combusts. The high-pressure pump and your injectors are designed to extremely fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against each other.
Of those two tasks, petrol handles the first badly and the second not at all. The knocking 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 runnier than diesel, it strips out the lubrication your system hinges on, and any pump working on such a mixture is wearing itself.
Put these together and the shape of the problem is clear. Contact does not do the damage — movement does. Petrol in the tank is a fuel fault. The start of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Four situations our engineers see around Ayr: how serious is petrol in a diesel?
Fuelled up, not once started. The best case there is. Just your tank has petrol in it, so the job is clearing your tank and cleaning the fuel system where the car sits. This scenario can only really happen at a forecourt: anywhere else, the car got there by being driven.
Started for a moment, or only the ignition on. Once primed, the system has drawn petrol from your tank as far as your filter and the lines. Drain, flush, see to your filter: still usually simple.
Your pump has spent a few miles on weakened fuel — that is what driving it meant. How hard the car was driven counts as much as how far, and this work takes in your tank, the lines, your filter and fresh fuel through the whole system. Short trips, such as the school run to the local primary school, are one thing. A run as far as Glasgow, under 50 miles away, is a very different task. So is any mileage on the M77, under 15 miles from Ayr, where your engine has been labouring hard throughout.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. What you are hearing is your motor reporting fuel that no longer runs like diesel. Whether it is the verge on Killoch Place, a lay-by or a side road, stop there then leave it. Long-term damage is very unusual when a car is pulled over soon, and the fuel drain and flush-through that still go first sort it out.
What Ayr motorists get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." A newer diesel runs its fuel through more precise parts at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches drivers. A petrol motor fed diesel usually will not run, so the motorist stops and the damage stops with them. Feed petrol to a diesel and it generally fires up, idles and drives away as if nothing happened — all while its pump wears. A running engine doesn't mean fine.
Myth: "Add some two-stroke oil and drive the car home." It's an old workaround for a different issue. None of what petrol diluted gets put back by it — and afterwards, your tank still contains the petrol.
Myth: "Drain the tank yourself and you are sorted." After your engine has run, some of the petrol is no longer in the tank: it is in the filter and the lines, and it goes right back through the pump on the next start. Emptying petrol into a can at the roadside is also really hazardous.
Why petrol in a diesel happens so easily
A careless moment is seldom the cause, and nobody means to do it. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it easy, and the error runs one way.
The moment routine stops matching your car is the moment it takes place. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. The pumps in a different order on a well-known forecourt. A train to catch, and a hurried fill en route to the nearest station. A new-to-you diesel Renault Clio, its first fuelling, and a motorist used to petrol: exactly when it occurs. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel on your next fill-up around Ayr
- The label is what counts, so check the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- The first fill in a new motor is the time to check the filler flap — on it, or on the cap, plenty of vehicles state the fuel they take.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key when a household has one of each. So mark it.
- "Diesel", out loud, before you lift the nozzle — each time a new or hired car gets its first tank. It seems silly. It works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away and keep your mind on the petrol pump.
- 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 only, never a reason to stop checking the label.
- Less petrol makes a thinner mix, and so stop as soon as you realise — while remembering that your next step is unchanged. It's still not to start the car.
Already put petrol in a diesel around Ayr?
Then, there's just a short order of things. Do not crank it, and do not switch your ignition on. Ask the staff to help you roll it clear of the petrol pump if you're still on the forecourt, whether that's BP or somewhere else. Ring 0333 366 0103 next, with three answers — the fuel, the approximate amount, and if it has run.
Say so if it was AdBlue rather than petrol: it is a separate fault, with its own page for Ayr, since AdBlue brings corrosion and deposits instead of lost lubrication.
Why one petrol in a diesel job in Ayr costs more than another
The four situations above are four separate jobs, so no single quote for this would be fair. Which of them you're in is chiefly what shifts the cost. Next it's the share — how much petrol got in against how much that tank takes — and then where the vehicle is and whether a technician can reach it safely.
What was put in, how much, and if it has run — three queries our engineers ask before quoting, not after, for exactly that reason. Given those answers, there is a straight figure instead of a range.
About Ayr, for a moment
Ayr is a coastal town in South Ayrshire, situated on the Firth of Clyde at a low elevation of around 14 metres. Ayr lies near several smaller communities, including Forehill, Wallacetown, and Craigie, and is approximately 32 miles from Glasgow. Ayr has a population of around 15970 people, predominantly living in flats. Ayr is also a significant distance from London, at around 330 miles away.
Fuel drain cover across South Ayrshire, Ayr included
Ayr sits in the KA postcode area, and our teams that answer petrol in diesel call-outs there work the locations around it as well — Forehill, Wallacetown and Craigie among them. Our engineers drain where the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the pump in Ayr, still?
No position is better: that is where you are. Keep the car switched off, and ring.