Should You Worry? Petrol in a Diesel Car in Humberstone
Not started? Then less anxious than you probably are. "Have I wrecked it?" is the first thing anyone around Humberstone asks, and the truthful answer is normally no, since petrol resting in a diesel tank hurts nothing until it's drawn through the system — by ignition priming, by the starter, or by driving. Keep it like that: leave your engine off and phone Petrol in Diesel. The remainder of this page explains what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to your engine
On its way through a motor, diesel has two jobs. It burns, and before it combusts it lubricates. What keeps the surfaces inside the high-pressure fuel pump and your injectors from wearing against one another is the diesel passing through them — they're made to very fine tolerances.
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, so a pump on that mixture to wear itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the rattling.
Taken together, they show the shape the issue has. Not contact but circulation is what does the damage. Petrol in a tank is a fuel issue. Whatever a worn pump sheds goes on, borne by your fuel, into the injectors further along, which is why a pump that has been working on the petrol is where a mechanical problem begins.
Four scenarios our technicians see in Humberstone: how serious is petrol in a diesel?
Filled but never started — the best it gets. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol kept inside that tank alone, it's emptied and cleaned on the spot, and nothing more is needed.
A moment's running, or just your ignition on. Once primed, the system has pulled petrol out of the tank up to the fuel filter and your lines. Usually little more than emptying, flushing and sorting the fuel filter, and so still straightforward.
The pump has spent a couple of miles on weakened fuel — that is what driving the vehicle does. Miles is only half of that; how hard it was driven matters just as much. Either way this work runs to your tank, the lines, the filter and fresh fuel through the entire system. The school run to Falcons Primary School is one matter. Very different once more: a trip to Leicester, under 3 miles away, or some mileage on the M1, under 10 miles from Humberstone, where the motor kept working hard.
Driven till it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer acting like diesel. Whether it is the verge on Greenland Drive, a lay-by or a side road, stop there and leave it. A vehicle stopped quickly very seldom has long-term damage, because the fuel drain and the flush-through, which still go first, take care of it.
Myths Humberstone people hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a current diesel copes with a bit of petrol. If anything, the opposite. A modern diesel runs its fuel through more precise components at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches drivers. Diesel in a petrol motor normally means a motor that won't run: the driver stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump wears. Being able to run is not the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. That petrol is still inside the tank after that, and whatever it has weakened isn't put back.
If the engine has run, part of that petrol is in the fuel filter and your lines, not that tank — and the next start pulls it right back through the pump. So the myth "drain your tank yourself and you're sorted" doesn't stand up. And, a can of petrol filled by the kerbside is truly dangerous.
Why petrol in a diesel happens at all
It is rarely carelessness, and nobody does it on purpose. 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 mostly won't go into a petrol motor at all. So the error runs one way.
It occurs when routine and the car stop matching. A new vehicle, a hire car or a courtesy car. Two motors on one drive, one petrol, one diesel. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill on the way to Leicester. Years of petrol cars behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that is when. Throw in rain, a phone call or a back seat full of kids, and the hand does what it has always done.
How to avoid petrol in a diesel at your next fill-up around Humberstone
- The label is what counts, so read the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- The first fill in an unfamiliar motor is the time to check your filler flap — inside it, or on the cap, many vehicles state the fuel they take.
- One of each in the home? Mark the key to your diesel — a bright fob, a sticker — because intending to remember is not enough.
- Before the nozzle leaves the pump the first time you fuel a hired or new motor, say "diesel" out loud. Daft, yes, yet it does the trick.
- Mistakes like this are simple to make while your mind is on something else, and so the phone goes away.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- Less petrol makes a weaker mixture, and so stop as soon as you notice — while remembering that your next step is unchanged. It's still not to start the vehicle.
Put petrol in a diesel in Humberstone already?
Then the order of things is short. Never crank it, and don't turn your ignition on. Still on the forecourt, at Shell or anywhere else? Ask the attendants to help you roll the car away from the petrol pump. What was put in, about how much, and if it has run: tell us those when you call 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different fault — Humberstone has a page all for it.
What makes one Humberstone petrol in a diesel task cost more than the next
An honest single price does not exist here: four situations, four separate jobs. Chiefly, your cost shifts with which situation you're in. Two things follow that: the petrol that was put in as a share of what that tank holds, then the spot your car is in and whether our van can reach it safely.
What went in, how much, and if it's run — three queries we ask before costing, not after, for precisely that reason. A range becomes a straight figure once the answers are in.
About Humberstone, for a moment
Humberstone is a suburban area in Leicestershire, situated near the River Soar and close to the city of Leicester. Humberstone has a mix of housing types, but semi-detached homes are predominant, and the area is relatively low-lying at an elevation of 71 metres. Humberstone is located near several other suburban areas, including North Evington and Crown Hills, and is also home to the Humberstone Garden. Humberstone is about 2.2 miles from Leicester city centre and 88.5 miles from London.
Fuel drain cover across Leicestershire, Humberstone included
Our vans answering petrol in diesel jobs around Humberstone, in the LE postcode area, also work the locations around it, North Evington, Crown Hills and Humberstone Garden included. Our engineers drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the pump around Humberstone?
Then you're in the best place there is. Switched off it stays; then ring.