Petrol in a Diesel Car in Passmonds: How Worried Should You Be?
Provided it hasn't been started, you can worry less than you probably are. Until your ignition primes your pump, your starter cranks, or the car is driven, petrol in a diesel tank just rests there and does nothing. Which makes the truthful reply to that first Passmonds question — "have I ruined it?" — usually no. Leave the engine off then call Petrol in Diesel — that keeps it like that. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that's the rest of this page.
Petrol in a diesel: what does it do to your engine?
Passing through an engine, diesel does two jobs at once. It lubricates first, and after that does it burn. Very fine clearances go into your injectors and the high-pressure fuel pump, and only the diesel running through keeps their surfaces from grinding together.
Badly at the first, not at all at the second: that's petrol. The rattling comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the system rests on, and any pump running on that mixture is wearing itself.
Taken together, they make clear the shape the issue takes. Not contact but circulation is what causes the harm. All a tank with petrol in it amounts to is a fuel issue. The start of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Passmonds, petrol in a diesel: four cases, from mild to serious
Filled up, not once started. The best case there is. The petrol is inside your tank and just that tank, and the task is a drain and a flush where the car sits. This is the one situation that can only truly occur on a forecourt, because anywhere else the vehicle has been driven to get there.
A moment's running, or merely the ignition on. With your system primed, the lines and filter already hold petrol that came from the tank. Drain, flush, deal with the fuel filter: still normally straightforward.
The pump has worked a couple of miles on diluted fuel — that is what driving it meant. The work is that tank, the lines, the filter and clean fuel through the whole circuit, and how hard your car was driven counts as much as how far. Short trips, such as the school run to St Vincent De Paul Roman Catholic Primary School, A Voluntary Academy, are one thing. Driving as far as Manchester, under 15 miles away, makes a very different job — as does any mileage on the A627(M), under 3 miles from Passmonds, with your engine labouring hard all the way.
Clattering, a ragged idle, smoke, a throttle gone soft: driven until it complained. The engine is telling you the fuel is no longer acting like diesel. Stop wherever you are — the verge on Whalley Gardens, a lay-by, a side street — then leave it there. What goes first is still the fuel drain and flush-through, and that takes care of it, with permanent damage very uncommon if a vehicle is pulled over soon.
Petrol in a diesel myths Passmonds motorists hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing comes out when you top up — your tank simply carries more of the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice assumes.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." Finer parts and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." A petrol engine fed diesel generally will not run, and so the motorist stops and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump grinds. A running engine does not mean fine.
Myth: "Add some two-stroke oil and drive the car home." It's an old workaround for a separate problem. It does not put back what petrol has diluted, and the petrol is still inside the tank later.
Myth: "Drain the tank yourself and you're sorted." After your engine has run, some of the petrol is no longer in the tank: it's in your filter and your lines, and it goes straight back through your pump at your next start. Also, a can of petrol filled by the kerbside is truly hazardous.
Petrol in a diesel: how does it take place?
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it easy: the petrol nozzle is the smaller 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 vehicle at all. So the slip runs one way.
Habit and the car getting out of step is how it happens. A motor that is new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a well-known forecourt. A rushed fill on the way to Rochdale with a train to catch. A new-to-you diesel Nissan Qashqai, its first fuelling, and a motorist accustomed to petrol: exactly when it happens. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to avoid petrol in a diesel on your next fill-up in Passmonds
- Read the pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what matters.
- Inspect your filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on the first fill in any motor you don't know.
- One of each in the house? Label your key to your diesel — a coloured fob, a sticker — because intending to remember is not enough.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds daft and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away and keep your mind on the pump.
- Add-on devices exist for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- Stop as soon as you realise. Less petrol inside your tank means a weaker mix. It doesn't change what to do next, which is still not to start the car.
Passmonds: already put petrol in a diesel?
Then the order of things is short. Never crank it, and do not turn your ignition on. Ask the attendants to help you push it clear of the pump if you are still on the forecourt, whether that's Esso or somewhere else. Then phone 0333 366 0103 and tell us what was put in, roughly how much, and if it has run.
If it was AdBlue rather than petrol, say so. That's a different problem — corrosion and deposits and not lost protection — and it has its own page for Passmonds.
What makes one Passmonds petrol in a diesel task cost more than the next
There's no fair single price for this, because the four situations above are four different jobs. Chiefly, the cost moves with which one you are in. Beyond that it's the ratio — how much petrol got in against how much your tank holds — and then where the car is and whether our van can reach it safely.
What went in, how much, and whether it has run — three questions our engineers ask before quoting, not after, for precisely that reason. A range becomes a straight figure once those replies are in.
About Passmonds itself
Passmonds is a suburban area in Greater Manchester, situated near the River Roch and characterised by semi-detached housing. Passmonds sits at an elevation of 156 metres, approximately 10 miles from Manchester city centre. Passmonds is part of a network of residential communities that include nearby Caldershaw, Greave, and Cutgate. Passmonds has a population of around 6474 people, living in a mix of old and new housing stock.
Passmonds and Greater Manchester: where our fuel drain cover reaches
Petrol in diesel jobs in Passmonds — part of the OL postcode area — go to vans that likewise cover the spots around it, Caldershaw, Greave and Cutgate included. Our engineers drain wherever your car 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 petrol pump in Passmonds?
The best place there is, then — that is where you are. Leave it turned off, then ring.