Petrol in a Diesel Car in Lower Dimson: How Worried Should You Be?
Unstarted? Then less worried than you probably feel. Until the ignition primes the pump, your starter cranks, or your vehicle is driven, petrol in a diesel tank simply waits there and does no harm. Which makes the honest reply to that first Lower Dimson query — "have I ruined it?" — usually no. Leave your motor off and call Petrol in Diesel — that is how you keep it that way. The remainder of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
What petrol in a diesel does to your engine
Two jobs fall to diesel on its journey through a motor. Oiling comes before burning; it does both. Made to very fine tolerances, the injectors and your pump rely on your diesel moving through them to stop their surfaces wearing against one another.
The second job petrol does not do at all, and the first it does poorly. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and takes away the protection your fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where any knocking comes.
The shape of the problem is plain once you put those together. Not contact but movement is what causes the damage. A tank with petrol in it is a fuel issue. After the pump has been working on that petrol, a mechanical problem has started: whatever is shed by a pump that is wearing down travels onward to your injectors with the fuel.
Petrol in a diesel around Lower Dimson: how bad is it? Four situations
Filled but not once started — the best it gets. That petrol is in that tank and only that tank, and the job is a drain and a flush where the car stands. This is the one situation that can only truly happen on a forecourt, as anywhere else the vehicle has been driven to get there.
The ignition switched on, or a brief start. Once primed, the fuel system has drawn petrol out of the tank as far as your filter and the fuel lines. That is normally still a simple task — a drain, a flush, and the filter seen to.
The pump now spent a couple of miles on thinned fuel — that is what driving it meant. Tank, lines, filter, then clean fuel run through the entire system: that is this work, and the way the car was driven counts as much as the distance. On the school run to Copper Valley Junior Academy, the miles is small. Very different once more: a trip to Plymouth, under 15 miles away, or any distance on the M5, under 50 miles from Lower Dimson, where your engine never stopped running hard.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. The fuel is not acting like diesel any more, and your engine is saying so. Stop where you are — on the verge on King Street, at the kerb, down a side road — and do not move it. A vehicle pulled over early very rarely has long-term damage, since the fuel drain and the flush, which still go first, deal with it.
Lower Dimson drivers and that petrol in a diesel myths they hear
Myth: topping up to full with diesel makes it fine. It doesn't. Topping up removes nothing; it gives you a bigger tank of the same mix. The idea behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. Lubrication matters more on current diesels, not less, since their fuel runs through more precise components at higher pressure.
This is the one that catches people. Myth: "If it starts and drives, there is no damage done." Feed diesel to a petrol motor and it usually won't run, so the motorist stops — and the damage stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, while the pump grinds. Running is not the same as fine.
Not so: a two-stroke additive lets you to drive home. It was an old workaround, supposed for another fault. What petrol has weakened stays diluted, and the petrol stays inside that tank regardless.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol sits in the filter and lines, waiting to go right back through the pump on your next start. On top of that, petrol drained into a can by the road is genuinely dangerous.
How does petrol in a diesel happen?
No one does it on purpose, and it's rarely carelessness. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it easy, and the slip runs one way.
It takes place when habit and the vehicle stop matching. A vehicle that's new to you — hired, on loan as a courtesy car, or brand new. Two motors on one driveway, one petrol, one diesel. A familiar forecourt with the pumps in a different order. Racing for a train at Gunnislake and fuelling up en route. A new-to-you diesel Volkswagen Tiguan, its first fuelling, and a driver used to petrol: precisely when it happens. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it always has.
Lower Dimson people: how to prevent petrol in a diesel next time
- The label is what counts, and so read the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- The first fill in a strange vehicle is the time to check your filler flap — on it, or on the cap, plenty of vehicles state which fuel they take.
- One of each in the home? Label your key to your diesel — a bright fob, a sticker — since intending to remember is not enough.
- Before the nozzle comes off the pump the first time you fill a hired or new vehicle, say "diesel" aloud. Silly, perhaps, but it works.
- Tuck the phone away. This is an easy mistake to make while you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop checking the petrol pump.
- Spotting it halfway? Stop there and then. A weaker mixture results from less petrol in that tank, yet your next stage remains the same: do not start it.
Already put petrol in a diesel in Lower Dimson?
Then the order of things is short. Do not turn the ignition on, and don't crank it. Ask the attendants to help you push it away from the pump if you're still at the forecourt, whether that's Asda or somewhere else. What went in, about how much, and if it has run: tell us those when you call 0333 366 0103.
If it was AdBlue and not petrol, say so. That is a separate issue — corrosion and deposits instead of lost lubrication — and it has its own page for Lower Dimson.
Lower Dimson petrol in a diesel jobs: why one costs more than another
There is no honest single quote for this, since the four situations above are four different tasks. Which of them you're in is mostly what moves the cost. The proportion counts next, meaning how much of that tank is petrol, followed by the position of the car and whether getting to it is safe for a technician.
What was put in, how much, and whether it's run — three questions we ask before quoting, not after, for exactly that reason. A range turns into a straight figure when those answers are in.
About Lower Dimson, for a moment
Lower Dimson is a suburban area situated on the riverside in Cornwall, with a mix of detached housing and a population of around 1361 residents. Lower Dimson sits at an elevation of 94 metres, close to the nearby settlements of Middle Dimson, Gunnislake, and North Dimson. Lower Dimson is located near the city of Plymouth, which is approximately 11 miles away, and is part of the wider South West region. Lower Dimson has a relatively small community, with easy access to the surrounding countryside.
Across Cornwall and in Lower Dimson: fuel drain cover
Lower Dimson rests in the PL postcode area, and the teams that answer petrol in diesel calls there work the places around it as well — Middle Dimson, Gunnislake and North Dimson among them. The vehicle does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Lower Dimson, right now?
The best place there is, then — that is where you are. Turned off it stays; then call.