How Worried Should You Be? Petrol in a Diesel Car in Birkenshaw
Likely less than you already are — as long as no one has started the vehicle. Till the ignition primes the pump, your starter cranks, or your car is driven, petrol in a diesel tank just rests there and does no harm. Which means the honest reply to that first Birkenshaw query — "have I ruined it?" — usually no. Petrol in Diesel is who to phone, with your motor left off, and so it remains that way. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to the engine
Two jobs fall to diesel on its route through a motor. It combusts, and before it combusts it protects. The high-pressure pump and your injectors are made to very fine gaps, and the diesel passing through them is what stops those surfaces from wearing down against one another.
Poorly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump on the mixture to wear itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the knocking.
Put those together and the shape of the trouble is clear. Contact doesn't do the damage — movement does. Where the petrol is only inside the tank, it is a fault of fuel, nothing more. The beginning of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors beyond it.
Birkenshaw, petrol in a diesel: four cases, from mild to serious
Fuelled but never started — the best it gets. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol held inside your tank alone, it is drained and cleaned on the spot, and nothing more is needed.
Started for a second, or only the ignition on. Your system has been bled, so petrol has left the tank and got to your filter and the lines. That's usually still an easy job — a drain, a flush, and the filter dealt with.
Driven a couple of miles. Now the pump has spent those miles working on weakened fuel. How hard the vehicle was driven counts as much as how far, and this work takes in that tank, the fuel lines, the fuel filter and clean fuel through the whole circuit. The school run to the local primary school is one thing. Very different once more: a trip to Glasgow, under 10 miles away, or any distance on the M74, under a mile from Birkenshaw, where your engine never stopped labouring hard.
Knocking, a ragged idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and the motor is saying so. Whether it's the verge on Second Street, a lay-by or a side road, stop there then leave it. A car stopped early very seldom has long-term damage, since the fuel drain and the flush-through, which still go first, take care of it.
Birkenshaw motorists and that petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that advice presumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. Smaller components and higher pressure are the way a current diesel runs its fuel, and that makes the protection count more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there's no harm done." A petrol engine fed diesel usually won't run, so the driver stops and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, whilst your pump wears. A running engine does not mean fine.
Not so: a two-stroke additive lets you to drive home. It was an old fix, meant for another problem. It doesn't put back what petrol has diluted, and the petrol is still in the tank later.
The next start draws petrol back round your pump from your lines and the filter, where some of that ends up after the motor has run. That is why a DIY tank drain doesn't leave you sorted — a myth. Besides, petrol drained into a can by the road is genuinely dangerous.
How it happens: petrol in a diesel
Nobody does it on purpose, and it is seldom carelessness. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol car at all. So the mistake runs one way.
It takes place when habit and the vehicle stop matching. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Rushing for a train outside Uddingston and filling up en route. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel on your next fill-up in Birkenshaw
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is just a hint.
- Many vehicles state the fuel type inside your filler flap or on the cap, so check it on your first fill in a vehicle you do not know.
- Mark the key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car gets its first tank. It sounds silly. It works.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Stop as soon as you realise. Less petrol inside the tank means a thinner mix. It doesn't change what to do next, which is still not to start the vehicle.
Petrol already in a diesel around Birkenshaw? Start here
In that case, there is just a short order of things. Do not turn the ignition on, and don't fire it up. If you are still on the forecourt — Gulf or anywhere else — ask the staff to help you roll the car clear of the pump. Then phone 0333 366 0103 and tell us what was put in, about how much, and if it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Birkenshaw has a page just for it.
Birkenshaw petrol in a diesel tasks: why one costs more than another
A fair single quote doesn't exist here: four scenarios, four separate tasks. Mostly, the cost shifts with which one you're in. The share matters next, meaning how much of the tank is petrol, followed by the position of your car and whether getting to it is safe for a van.
That's why our engineers ask three questions before quoting rather than after: what was put in, how much, and if it has run. Those replies are what turn a range into one firm number.
About Birkenshaw itself
Birkenshaw is a suburban area situated on the riverside in North Lanarkshire, with a mix of semi-detached housing and local amenities. Birkenshaw lies close to the city of Glasgow, approximately 6 miles to the northwest, and is near other suburban areas such as Calderbraes and Tannochside. Birkenshaw has a relatively low elevation of around 68 metres above sea level, and its population is approximately 4469 residents. Birkenshaw is also within commuting distance to Glasgow, making it a popular choice for those working in the city.
Birkenshaw and North Lanarkshire: where our fuel drain cover runs
Petrol in diesel call-outs in Birkenshaw — part of the G postcode area — go to teams that also cover the locations about it, Calderbraes, Tannochside and Kylepark included. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers work, and the car does not need to move to us.
Birkenshaw: still at the pump?
In that case, you could not be in a better spot. Call, and keep it turned off.