Petrol in a Diesel Car in Cross Roads: How Worried Should You Be?
Provided it has not been started, worry far less than you likely are. "Have I wrecked it?" is the first question anyone around Cross Roads asks, and the truthful answer is generally no, since petrol resting in a diesel tank harms nothing until it is drawn through the fuel system — by ignition priming, by the starter, or by being driven. Petrol in Diesel is who to ring, with your motor left off, and so it remains that way. What petrol really does to a diesel, how to gauge how far it has gone, and how to stop it from happening again: that is the remainder of this page.
What petrol in a diesel does to the motor
On its way through a motor, diesel does two tasks. Oiling comes before burning; it does both. Extremely fine clearances go into the injectors and the high-pressure pump, and only your diesel flowing through stops their surfaces grinding together.
The second task petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the system hinges on, and any pump running on that mixture is wearing itself.
The shape of the trouble is clear when you put those together. It is circulation that does the damage, not contact. Where that petrol is only in that tank, it's an issue of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the fuel injectors further on.
Petrol in a diesel around Cross Roads: how serious is it? Four situations
Fuelled, and not started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol kept inside the tank alone, it is emptied and cleaned on the spot, and nothing more is needed.
The ignition turned on, or a short start. Once primed, the system has pulled petrol out of the tank as far as the fuel filter and the fuel lines. That's normally still an easy task — a drain, a flush, and the fuel filter dealt with.
A few miles driven, and your pump has spent every one of them running on diluted fuel. The work is the tank, your lines, the fuel filter and fresh fuel through the whole circuit, and how hard your car was driven counts as much as how far. Driving the kids to Lees Primary School is one sort of trip. Very different a second time: a run to Bradford, under 10 miles away, or some distance on the M606, under 10 miles from Cross Roads, where your engine never stopped labouring hard.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. That is your engine telling you its fuel has stopped acting like diesel. Whether it is the verge on Lorne Street, a lay-by or a side street, stop where you are then leave it. Permanent damage is very rare when a vehicle is stopped early, and the drain and flush that still go first deal with it.
Petrol in a diesel myths Cross Roads people hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That advice assumes a diesel fuel system tolerates petrol by percentage. It does not.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Protection matters more on current diesels, not less, because their fuel passes through finer components at higher pressure.
"It starts, it drives, so there is no harm" — the myth that catches more people than any other. The driver of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. Feed petrol to a diesel and it generally fires up, ticks over and pulls away like nothing happened — all while its pump is wearing. Fine and running aren't the same thing.
An old fix for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive the car home." The petrol is still inside the tank afterwards, and whatever it has thinned isn't put back.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol lies in your filter and lines, ready to go right back through your pump at your next start. Also, a can of petrol drained by the kerbside is genuinely risky.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. A diesel nozzle generally will not go into a petrol motor, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake simple, and only in that direction.
When routine and your car stop matching, it occurs. A new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A forecourt you know, only with its pumps laid out differently. Rushing for a train at Keighley and filling up en route. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: exactly when it occurs. Throw in a back seat full of children, a phone call or rain, and the hand wins.
Cross Roads drivers: how to prevent petrol in a diesel next time
- Read the 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.
- Plenty of motors state the fuel type inside your filler flap or on the cap, and so check it on the first fill in any motor you do not know.
- One of each in the household? Mark the key to your diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- Before the nozzle comes off the pump the first time you fuel a hired or new car, say "diesel" out loud. Daft, yes, yet it does the trick.
- Tuck your phone away. This is an easy mistake to make whilst you are thinking about something else.
- Add-on devices are available for motors without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- Less petrol makes a thinner mixture, and so stop as soon as you notice — though remembering that your next step is unchanged. It is still not to fire it up.
Cross Roads: already put petrol in a diesel?
The order of things is brief, then. Do not switch your ignition on, and do not fire it up. If you're still at the forecourt — Shell or anywhere else — ask the attendants to help you push the vehicle away from the petrol pump. What was put in, about how much, and whether it has run: tell us those when you call 0333 366 0103.
Say so if it was AdBlue instead of petrol: it is a different fault, with its own page for Cross Roads, since AdBlue brings corrosion and deposits rather than lost lubrication.
What makes one Cross Roads petrol in a diesel job cost more than the next
There is no honest single quote for this, since the four situations above are four different jobs. What moves the cost is mostly which of them you are in. Where the vehicle is counts too, and whether a technician can safely get to it, after the share of petrol to what your tank takes.
What went in, how much, and whether it has run — three questions our technicians ask before quoting, not after, for exactly that reason. Those replies turn a range into a straight figure.
About Cross Roads and where it is
Cross Roads is a suburban area in West Yorkshire, situated near several lakes and reservoirs at an elevation of 226 metres. Cross Roads is located close to the cities of Bradford and Leeds, and is part of a larger network of residential communities in the region. Cross Roads has a mix of housing types, but is predominantly characterized by terraced homes. Cross Roads is also near several smaller communities, including Lane End and Barcroft.
Across West Yorkshire and around Cross Roads: fuel drain cover
Petrol in diesel call-outs in Cross Roads — part of the BD postcode area — go to vans that also cover the places around it, Lane End, Barcroft and Lees among them. The car doesn't need to move 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 pump in Cross Roads?
In that case, you couldn't be in a better place. Leave it turned off, then ring.