How Worried Should You Be? Petrol in a Diesel Car in Wheelock
Not started? Then less worried than you likely feel. Until the ignition primes the pump, your starter turns, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to that first Wheelock question — "have I ruined it?" — normally no. Keep it like that: leave the motor off then ring Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you don't do it again.
Your engine and petrol in a diesel: what happens
On its way through a motor, diesel has two jobs. It protects first, and after that does it burn. Built to very fine clearances, the fuel injectors and your pump rely on the diesel flowing through them to keep their surfaces from wearing against one another.
Petrol handles the first task poorly and the second not at all. A pump working on a petrol blend is wearing itself out, since petrol is thinner than diesel and strips out the lubrication the fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where any knocking starts.
Combined, those make the shape of the issue plain. It is circulation that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. Once the pump has been labouring on that petrol, a mechanical fault has started: anything shed by a pump that's wearing is carried downstream to your injectors with the fuel.
Petrol in a diesel in Wheelock: how bad is it? Four cases
Filled up, and not started: no case is better. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With the petrol kept inside that tank alone, it's cleared and flushed on the spot, and nothing more is needed.
A brief spell of running, or just your ignition on. With your system primed, the lines and filter now contain petrol that has come from that tank. Usually nothing more than draining, flushing and sorting the filter, so still straightforward.
Those few miles on the road were your pump working on fuel thinned by petrol the whole way. Tank, lines, filter, then clean fuel run through the entire circuit: that is this work, and the way your car was driven matters as much as the distance. Driving the kids to Wheelock Primary School is one sort of trip. Getting as far as Stoke-on-Trent, under 15 miles away, makes a very different job — as does any distance on the M6, under 3 miles from Wheelock, with the engine running hard the whole time.
Rattling, a ragged idle, smoke, a throttle gone soft: driven until it complained. The fuel is not acting like diesel any more, and your motor is telling you. Pull up wherever you are — the verge on Mill Lane, a lay-by, a side street — and leave it there. The drain and flush still come first, and they take care of it: when a car is stopped early, permanent damage is very rare.
Petrol in a diesel myths Wheelock motorists hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. The assumption behind that advice — 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. More precise parts and higher pressure are the way a newer diesel runs its fuel, and that makes the protection count more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools drivers. A petrol motor fed diesel usually will not run, so the motorist stops and the damage stops with them. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while your 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, borrowed from a fix from years ago, for a different problem. None of what petrol diluted gets put back by it — and later, the tank still contains that petrol.
If the engine has run, part of that petrol is in the fuel filter and your lines, not your tank — and the next start sends it right back through the pump. So the myth "drain your tank yourself and you are sorted" does not hold. Clearing petrol into a can by the roadside is also genuinely dangerous.
How does petrol in a diesel occur?
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol car at all. So the mistake runs one way.
When routine and the vehicle stop matching, it takes place. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. Your usual forecourt, its pumps now in a different order. A train to catch, and a rushed fill on the way to Sandbach. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to prevent petrol in a diesel on your next fill-up in Wheelock
- A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Go by the label on the petrol pump, not the colour.
- Plenty of motors state the fuel type inside your filler flap or on the cap, so check it on the first fill in any car you don't know.
- Label 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.
- It sounds silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- Less petrol means a thinner blend, so stop the moment you realise — while remembering that your next step is unchanged. It is still not to start it.
Already put petrol in a diesel in Wheelock?
Then the order of things is short. Starting it is out, and so is turning on the ignition. Still on the forecourt, at BP or anywhere else? Ask the attendants to help you roll the car clear of the petrol pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate fault — Wheelock has a page just for it.
Why one petrol in a diesel job around Wheelock costs more than another
An honest single price does not exist here: four scenarios, four separate tasks. What shifts the cost is mostly which of them you are in. Two things come after that: the petrol that got in as a proportion of what that tank holds, then the spot your car is in and whether a technician can get to it safely.
Before any quote, not after, we ask three queries: your fuel that got in, its amount, and if it's run. That is why. Those replies are what turn a range into one firm number.
About Wheelock itself
Wheelock is a village in Cheshire, situated on the banks of the River Dane at an elevation of around 52 metres. Wheelock lies near the Potteries region, with Stoke-on-Trent approximately 11 miles to the east, and is surrounded by areas such as Malkins Bank and Wheelock Heath. Wheelock has a population of around 1342 people, predominantly living in semi-detached housing. Wheelock is located about 146.7 miles northwest of London, in the North West region of England.
Wheelock and Cheshire: where our fuel drain cover reaches
Petrol in diesel call-outs around Wheelock — part of the CW postcode area — go to teams that also cover the locations about it, Malkins Bank, Wheelock Heath and Cold Moss Heath among them. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations we drain.
In Wheelock and still at the petrol pump?
The best position there is, then — that is where you are. Leave it turned off, then ring.