Petrol in a Diesel Car in Shirley: How Worried Should You Be?
Unstarted? Then less worried than you likely feel. Everyone around Shirley starts with "have I ruined it?", and the fair answer is normally no: petrol resting in your tank of a diesel stays harmless until priming, cranking or driving draws it into the fuel system. To leave the vehicle like that, phone Petrol in Diesel then leave the engine switched off. Further down, you will find what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you again.
Inside the engine: what petrol in a diesel really does
On its way through a motor, diesel has two tasks. Before it combusts, it lubricates — then it combusts. Designed to very fine clearances, the injectors and your pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
The second task petrol doesn't 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 relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where any knocking starts.
Put these together and the shape of the trouble is clear. Contact doesn't do the harm — circulation does. Where that petrol is only in that tank, it is a fault of fuel, nothing more. Once your pump has been running on that petrol, a mechanical problem has started: whatever is shed by a pump that's grinding travels downstream to your injectors with your fuel.
How serious is petrol in a diesel? Four scenarios we see around Shirley
Fuelled but never started — as good as it gets. That petrol is in that tank and just the tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only truly happen on a forecourt, since anywhere else the vehicle has been driven to get there.
A moment's running, or merely the ignition on. Once primed, the system has pulled petrol out of the tank as far as the fuel filter and your lines. Still usually straightforward: drain, flush, and your filter sorted.
A couple of miles driven, and your pump has spent every one of them working on thinned fuel. The work is your tank, the fuel lines, the fuel filter and clean fuel through the entire system, and how hard your car was driven counts as much as how far. Short trips, like the school run to Robin Hood Academy, are one matter. Driving as far as Birmingham, under 10 miles away, makes a very different job — as does any distance on the M42, under 5 miles from Shirley, with your engine working hard the whole time.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The motor is telling you the fuel is no longer behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Chadwell Drive. The drain and flush still go first, and they take care of it: if a car is pulled over quickly, long-term damage is very rare.
Shirley people and the petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A fuller tank of the same mixture is all you get, because topping up takes out nothing. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance supposes.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. Protection matters more on newer diesels, not less, since their fuel runs through smaller components at higher pressure.
This is the one that catches drivers. Myth: "If it starts and drives, there's no harm done." Feed diesel to a petrol motor and it generally won't run, and so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it usually starts, idles and drives away like nothing has happened — all the while its pump is wearing. Running doesn't mean fine.
An outdated workaround for a different issue lies behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted remains weakened, and that petrol remains inside the tank regardless.
Myth: "Drain the tank yourself and you are sorted." Once the motor has been run, some of the petrol is no longer inside the tank: it is in the filter and the fuel lines, and it goes right back through the pump on the next start. Also, a can of petrol filled at the roadside is genuinely hazardous.
How does petrol in a diesel occur?
It's rarely carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol motor, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and just in one direction.
The moment habit stops matching the car is the moment it happens. Courtesy car, hire car, or a vehicle that is new. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A rushed fill on the way to Yardley Wood with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
Next time you fill up in Shirley: preventing petrol in a diesel
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on each forecourt. The label is what counts.
- Many cars state the fuel type inside your filler flap or on the cap, so check it on your first fill in any vehicle you don't know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key if a home has one of each. So mark it.
- Before the nozzle comes off the pump the first time you fuel a hired or new vehicle, say "diesel" out loud. Daft, yes, yet it works.
- Mistakes like this are straightforward to make while your mind is on something else, and so the phone goes away.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- Less petrol makes a weaker mix, and so stop as soon as you realise — though remembering that your next stage is unchanged. It's still not to fire it up.
Put petrol in a diesel around Shirley already?
The order of things is short, then. Don't switch the ignition on, and don't start it. Still at the forecourt, at Asda or anywhere else? Ask the staff to help you roll it away from the pump. Then ring 0333 366 0103 and tell us what was put in, roughly how much, and if it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and see its own Shirley page.
What makes one Shirley petrol in a diesel job cost more than the next
There is no honest single quote for this, since the four scenarios above are four separate tasks. Which of them you are in is chiefly what moves your cost. Where the car is matters too, and whether our van can safely get to it, after the proportion of petrol to what the tank takes.
What went in, how much, and if it has run — three questions our technicians ask before quoting, not after, for precisely that reason. A range turns into a straight figure when the replies are in.
About Shirley, briefly
Shirley is a suburban area in the West Midlands, situated approximately 5 miles south of Birmingham city centre. Shirley sits at an elevation of around 153 metres, in a gently sloping landscape of inland England. Shirley is characterised by its predominantly semi-detached housing stock, with nearby neighbourhoods including Hall Green and Kineton Green. Shirley is home to around 6838 residents, according to recent estimates.
Across West Midlands and around Shirley: fuel drain cover
Hall Green, Kineton Green and Sharmans Cross are among the locations near Shirley that the same vans work, answering petrol in diesel calls across Shirley's B postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all places our technicians work, and the car does not need to come to us.
In Shirley and still at the petrol pump?
Then you're in the best place there can be. Switched off it remains; then phone.