How Worried Should You Be? Petrol in a Diesel Car in Downs Barn
Far less than you probably are, if it hasn't been started. Petrol resting in a diesel tank does nothing to your engine until something pulls it through the fuel system — the ignition priming your pump, the starter, or the drive on its own. So the honest answer to the first question anyone in Downs Barn asks, "have I ruined it?", is generally no. Petrol in Diesel is who to phone, with your motor kept off, and so it stays that way. What petrol really does to a diesel, how to gauge how far it has gone, and how to stop it from happening again: that is the remainder of this page.
Your engine and petrol in a diesel: what goes on
Diesel has two jobs on its way through a motor. It combusts, and before it ignites it lubricates. Built to very fine gaps, the fuel injectors and your pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that is petrol. It's thinner than diesel and removes the protection the fuel system rests on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the rattling comes from.
The shape of the trouble is clear once you put those together. It's circulation that causes the damage, not contact. Petrol in the tank is a fuel issue. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
How bad is petrol in a diesel? Four scenarios our engineers see in Downs Barn
Fuelled but not once started — the best it gets. On a forecourt, and genuinely only there, the petrol is still limited to that tank — since anywhere else the car was driven to get to it. The job is emptying and flushing on the spot.
A moment's running, or just your ignition on. Your system has been primed, so petrol has left the tank and got to the fuel filter and your lines. Still generally easy: drain, flush, and the filter dealt with.
Driven a couple of miles. Now the pump has spent those miles working on thinned fuel. Miles is only half of it; how hard it was driven counts just as much. Either way this work includes that tank, your lines, the filter and fresh fuel through the whole circuit. A school run to Downs Barn School is one matter. Driving as far as Milton Keynes, under 3 miles away, makes a very different job — as does any distance on the M1, under 3 miles from Downs Barn, with your engine running hard the whole time.
Rattling, a ragged idle, smoke, a throttle gone soft: driven till it complained. The motor is telling you the fuel is no longer acting like diesel. Whether it is the verge on Armourer Drive, a lay-by or a side road, stop where you are and leave it. Lasting damage is very unusual if a car is stopped quickly, and the fuel drain and flush that still come first sort it out.
Downs Barn motorists and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up takes out nothing; it gives you a bigger tank of the same mixture. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
"Current diesels can handle a little petrol" — a myth, and closer to the reverse. More precise parts and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it normally will not run, so the motorist stops — and the harm stops with them. While your pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Fine and running aren't the same at all.
Myth: "Add some two-stroke oil and drive it home." It's an outdated fix for a separate problem. None of what petrol weakened gets put back by it — and afterwards, your tank still holds the petrol.
Once the engine has been run, part of that petrol is in the filter and your lines, not that tank — and the next start pulls it straight back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. Besides, petrol drained into a can by the road is truly dangerous.
Petrol in a diesel: how does it happen?
No one does it on purpose, and it is seldom carelessness. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol motor. That's how the forecourt makes it easy.
It happens when habit and the car stop matching. Courtesy car, hire car, or a vehicle that is brand new. A household with one petrol and one diesel on the drive. A well-known forecourt with the pumps in a different order. Racing for a train at Milton Keynes Central and fuelling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a motorist accustomed to petrol: exactly when it occurs. With rain, a call coming in, or children to deal with, your hand just does what it has always done.
Next time you fill up around Downs Barn: avoiding petrol in a diesel
- The label is what matters, and so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- In a motor you do not know, look inside the flap over the filler or at the cap before your first fill: many motors state the fuel type there.
- Label your key. In a home 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 — every 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, and so tuck your phone away and keep your mind on the petrol pump.
- Some diesels come with a filler designed to reject a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump.
- Stop as soon as you notice. Less petrol inside your tank means a thinner blend. It does not change what to do next, which is still not to start it.
Already put petrol in a diesel around Downs Barn?
Then the order of things is brief. Never fire it up, and do not switch the ignition on. Ask the attendants to help you push it away from the petrol pump if you are still on the forecourt, whether that's BP or somewhere else. What was put in, roughly how much, and if it's run: tell us those when you call 0333 366 0103.
Corrosion and deposits form the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Downs Barn page.
What makes one Downs Barn petrol in a diesel job cost more than the next
A fair single quote doesn't exist here: four scenarios, four separate tasks. Which of them you are in is mostly what moves your cost. Next it's the proportion — how much petrol got in against how much the tank takes — and after that where the car is and whether a van can get to it safely.
That is why our engineers ask three questions before pricing instead of after: what went in, how much, and if it has run. Given those replies, you get a straight figure instead of a range.
About Downs Barn itself
Downs Barn is a suburban area located on the outskirts of Milton Keynes in Buckinghamshire, situated near the banks of a river at an elevation of around 85 metres. Downs Barn sits in close proximity to several nearby places, including Neath Hill, Pennyland, and Downhead Park, and is characterized by its predominantly terraced housing. Downs Barn is also within commuting distance to London, approximately 46 miles away.
Across Buckinghamshire and around Downs Barn: fuel drain cover
Our vans answering petrol in diesel calls around Downs Barn, in the MK postcode area, equally work the spots near it, Neath Hill, Pennyland and Downhead Park among them. The vehicle does not need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the petrol pump around Downs Barn?
Then you're in the best place there can be. Leave the car switched off, and ring.