Mannings Heath: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as nobody has started the car. Petrol sitting in a diesel tank does nothing to the engine until something pulls it through your fuel system — your ignition priming the pump, your starter, or driving on its own. So the fair answer to the first query everyone around Mannings Heath asks, "have I wrecked it?", is usually no. To keep it like that, ring Petrol in Diesel then leave the engine alone. What petrol actually does to a diesel, how to judge how far it has gone, and how to stop it from happening again: that's the rest of this page.
Inside the engine: what petrol in a diesel really does
On its way through an engine, diesel does two jobs. Before it ignites, it lubricates — and then it burns. Built to very fine clearances, the injectors and your pump depend on your diesel flowing through them to stop their surfaces wearing against one another.
The second job petrol doesn't do at all, and the first it does badly. The rattling comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication your system rests on, and any pump running on that blend is wearing itself.
The shape of the problem is plain once you put those together. Not contact but circulation is what does the harm. All a tank with petrol in it amounts to is a fuel problem. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
Mannings Heath, petrol in a diesel: four cases, from mild to significant
Fuelled, and not started: nothing beats it. At a forecourt, and genuinely only there, the petrol is still confined to your tank — because everywhere else the vehicle was driven to get to it. The job is draining and purging on the spot.
Ignition on, or started for a second. Once primed, your system has pulled petrol out of your tank up to your filter and the fuel lines. Normally nothing more than draining, rinsing and seeing to the filter, so still easy.
Some miles driven, and your pump has spent each of them running on thinned fuel. Tank, lines, filter, then clean fuel put through the entire system: that's this work, and the way the car was driven counts as much as the miles. Driving the kids to Heron Way Primary School is one sort of trip. Any miles on the M23, under 5 miles from Mannings Heath, means the engine has worked hard throughout, and a run to Brighton and Hove, under 25 miles away, makes a very different task as well.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. What you are hearing is your engine reporting fuel that no longer acts like diesel. Stop wherever you are — the verge on Winterpit Lane, a lay-by, a side street — then leave it where it is. The drain and flush-through still go first, and they take care of it: if a vehicle is pulled over soon, lasting damage is very unusual.
Myths Mannings Heath motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A fuller tank of the same mixture is all you get, since topping up takes out nothing. The idea behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. Finer components and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication count more, not less.
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 generally will not run, so the motorist stops — and the damage stops with them. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, whilst the pump grinds. Being able to run isn't 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 fault. None of what petrol thinned gets put back by it — and afterwards, that tank still contains that petrol.
The next start draws petrol back round the pump from the lines and the fuel filter, where some of it sits after the motor has run. That is why draining the tank yourself doesn't sort it — a myth. Also, a can of petrol drained by the roadside is genuinely dangerous.
Why petrol in a diesel happens at all
It's seldom carelessness, and nobody does it on purpose. A diesel nozzle mostly won't go into a petrol car, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in that direction.
When routine and the vehicle stop matching, it occurs. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps laid out differently. A train to catch, and a rushed fill en route to Horsham. A new-to-you diesel Renault Clio, its first fuelling, and a driver used to petrol: exactly when it occurs. Add a back seat full of children, a phone call or rain, and the hand wins.
Next time you fill up in Mannings Heath: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is just a clue.
- In a motor you don't know, look inside the flap over your filler or at the cap before your first fill: plenty of motors state the fuel there.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, in a household with one of each.
- Before the nozzle comes off the pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Daft, yes, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop reading the pump.
- The moment you notice, stop: less petrol inside the tank makes a thinner mix. What to do next doesn't change, though — still don't fire it up.
Mannings Heath: already put petrol in a diesel?
Then the order of things is short. Do not turn your ignition on, and do not crank it. Ask the attendants to help you roll it away from the petrol pump if you are still at the forecourt, whether that's Texaco or anywhere else. Then call 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
If it was AdBlue instead of petrol, say so. That is a different fault — corrosion and deposits rather than lost protection — and it has its own page for Mannings Heath.
What makes one Mannings Heath petrol in a diesel job cost more than the next
There's no fair single quote for this, since the four scenarios above are four separate tasks. What moves the cost is chiefly which of them you're in. Two things come after that: the petrol that went in as a proportion of what your tank takes, then the place the vehicle is in and whether a technician can reach it safely.
Three questions come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. Given those answers, there is a straight figure rather than a range.
About Mannings Heath and where it is
Mannings Heath is a village in West Sussex, situated near the riverside at an elevation of 74 metres, with detached housing being the predominant type of accommodation. Mannings Heath lies close to several nearby places, including Monks Gate, Doomsday Green, and Plummers Plain. Mannings Heath is located approximately 16.5 miles from Brighton and Hove and 32.7 miles from London. Mannings Heath has a population of around 806 residents.
Across West Sussex and in Mannings Heath: fuel drain cover
Petrol in diesel jobs in Mannings Heath — part of the RH postcode area — go to vans that likewise cover the locations around it, Monks Gate, Doomsday Green and Plummers Plain included. Our engineers drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump around Mannings Heath, still?
No position is better: that's where you are. Phone, and leave it switched off.