Nar: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as no one has started the vehicle. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the fuel system — your ignition priming the pump, your starter, or driving itself. So the truthful answer to the first question everyone in Nar asks, "have I ruined it?", is normally no. To keep the car like that, ring Petrol in Diesel then leave your engine alone. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you don't repeat it.
Inside the engine: what petrol in a diesel really does
On its way through an engine, diesel has two jobs. Oiling comes before burning; it does both. Designed to very fine tolerances, your injectors and your pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that is petrol. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and takes away the lubrication the fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where any knocking starts.
Put those together and the shape of the trouble is plain. Not contact but circulation is what causes the damage. Petrol in the tank is a fuel fault. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors further on.
Petrol in a diesel around Nar: how serious is it? Four cases
Fuelled, and never started: nothing beats it. Just your tank has petrol in it, so the job is emptying your tank and flushing the system where your car stands. This situation can only really take place on a forecourt: anywhere else, the vehicle got there by being driven.
Started for a moment, or just the ignition on. Once primed, the fuel system has pulled petrol from the tank as far as the filter and your lines. Normally nothing more than clearing, rinsing and sorting your filter, and so still straightforward.
Those few miles on the road meant your pump labouring on fuel thinned by petrol throughout. How hard the car was driven counts as much as how far, and the work covers that tank, your lines, the fuel filter and fresh fuel through the entire system. On the school run to Shawclough Community Primary School, the miles is short. Very different a second time: a trip to Manchester, under 15 miles away, or any mileage on the A627(M), under 3 miles from Nar, where the motor kept working hard.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. The fuel is not acting like diesel any more, and your motor is saying so. Leave it wherever it has stopped: a lay-by, a side street, the verge on Toad Leach Lane. A car pulled over early very rarely has long-term damage, as the fuel drain and the flush-through, which still come first, deal with it.
Nar motorists and the petrol in a diesel myths they hear
Myth: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a bigger tank of the same mix. Percentage is not how a diesel fuel system copes with petrol, however much that guidance presumes.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." Protection counts more on modern diesels, not less, since their fuel runs through smaller components at higher pressure.
This is the one that fools drivers. Myth: "If it starts and drives, there is no damage done." Feed diesel to a petrol engine and it usually will not run, so the driver stops — and the harm stops with them. Feed petrol to a diesel and it normally starts, ticks over and drives away as if nothing has happened — all the while its pump wears. Being able to run is not the same as being fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another problem. What petrol has thinned stays weakened, and that petrol remains in that tank regardless.
Myth: "Drain the tank yourself and you are sorted." After the engine has run, some of the petrol is no longer inside your tank: it is in your filter and the lines, and it goes right back through the pump at your next start. Also, a can of petrol drained at the kerbside is truly risky.
Why petrol in a diesel happens so easily
Nobody does it on purpose, and it's rarely carelessness. A diesel nozzle generally will not fit a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in one direction.
It takes place when routine and the vehicle stop matching. A car that's new to you — a hire car, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the driveway. A forecourt you know, but with its pumps arranged differently. Rushing for a train outside Rochdale and fuelling up en route. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Nar motorists: how to avoid petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the pump's label; the colour is just a hint.
- Many vehicles state the fuel inside the filler flap or on the cap, and so check it on the first fill in a motor you do not know.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key when a household has one of each. So mark it.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" aloud. Daft, yes, but it works.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a safety net, then keep reading the petrol pump.
- The moment you realise, stop: less petrol in the tank means a weaker blend. What to do next does not change, though — still don't crank it.
Put petrol in a diesel around Nar already?
The order of things is brief, then. Starting it is out, and so is switching on your ignition. Ask the staff to help you push it away from the pump if you're still on the forecourt, whether that is Texaco or anywhere else. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it is a separate issue, with its own page for Nar, since AdBlue brings corrosion and deposits instead of lost lubrication.
Nar petrol in a diesel tasks: why one costs more than another
The four scenarios above are four different jobs, so no single price for this would be fair. Chiefly, the cost moves with which one you are in. Two things follow that: the petrol that was put in as a share of what that tank holds, then the spot the car is in and whether our van can reach it safely.
That is why our technicians ask three questions before pricing instead of after: what went in, how much, and if it's run. A range turns into a straight figure once those replies are in.
About Nar itself
Nar is a small hamlet situated on the lakeside in Lancashire, with an elevation of 242 metres. Nar sits near several other small communities, including Middle Healey, Lower Healey, and Syke. Nar is located approximately 11.6 miles from Manchester, making it a relatively accessible rural area. Nar has a population of around 545 people, predominantly living in semi-detached housing.
Nar and Lancashire: where our fuel drain cover runs
Nar rests in the OL postcode area, and the teams that answer petrol in diesel jobs there work the locations around it as well — Middle Healey, Lower Healey and Syke among them. The vehicle does not need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the petrol pump around Nar?
Then, you couldn't be in a better spot. Keep it off. Ring.