Gulval: Petrol in a Diesel Car? How Worried to Be
Not started? Then less anxious than you probably are. Till your ignition primes your pump, your starter turns, or the vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which means the honest reply to the first Gulval question — "have I wrecked it?" — usually no. Leave the motor off then phone Petrol in Diesel — that is how you keep it that way. What petrol actually does to a diesel, how to gauge how far it's gone, and how to stop it from happening again: that's the rest of this page.
What petrol in a diesel does to the engine
Two tasks fall to diesel on its route round a motor. Oiling comes before burning; it does both. Made to very fine clearances, your injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
The second job petrol does not do at all, and the first it does badly. 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 thinner than diesel, it strips away the protection your system rests on, and any pump running on that blend is wearing itself.
Taken together, they show what shape the issue takes. Not contact but circulation is what does the damage. Petrol in the tank is a fuel problem. Whatever a worn pump sheds goes on, carried by your fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical issue begins.
Gulval, petrol in a diesel: four cases, from mild to major
Filled up, never started. The best case there can be. On a forecourt, and truly only there, that petrol is still limited to your tank — since everywhere else the vehicle was driven to get to it. The job is emptying and flushing on the spot.
Ignition on, or started for a second. With your system primed, the fuel lines and filter now hold petrol that has come from that tank. Normally little more than clearing, purging and sorting your filter, and so still simple.
The pump has worked a couple of miles on thinned fuel — that is what driving it does. The work is that tank, the fuel lines, your filter and clean fuel through the whole system, and how hard your car was driven counts as much as how far. A school run to Gulval School is one thing. Very different a second time: a run to Truro, under 25 miles away, or any distance on the M5, over 50 miles from Gulval, where the engine never stopped working hard.
Driven till it complained. Clattering, an uneven idle, smoke, a throttle that has gone soft. What you are hearing is your engine signalling fuel that no longer runs like diesel. Stop where you are — on the verge on School Lane, at the kerb, down a side road — and do not move it again. Permanent damage is very uncommon if a car is pulled over early, and the drain and flush that still come first sort it out.
Gulval people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. A fuller tank of the same mixture is all it gives, because topping up takes out nothing. Percentage is not how a diesel fuel system copes with petrol, however much that guidance presumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. A modern diesel sends its fuel through more precise components at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that catches motorists. The driver of a petrol motor fed diesel normally has no choice but to stop, because it will not run, and the damage stops with them. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, whilst the pump grinds. Running isn't the same as fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, meant for another problem. It does not put back what petrol has diluted, and the petrol is still in the tank later on.
The next start sends petrol back round your pump out of the lines and the filter, where some of that ends up once the motor has been run. That is why draining your tank yourself does not leave you sorted — a myth. Emptying petrol into a can at the roadside is also truly risky.
How does petrol in a diesel take place?
It is seldom carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol car at all. So the mistake runs one way.
The moment routine stops matching the vehicle is the moment it takes place. A motor that is new to you — a hire car, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Penzance. A new-to-you diesel Volkswagen Passat, its first fuelling, and a driver accustomed to petrol: precisely when it happens. Add a back seat full of children, a phone call or rain, and habit takes over.
Avoiding petrol in a diesel next time you fill up around Gulval
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is only a hint.
- Plenty of vehicles state the fuel type inside the filler flap or on the cap, and so check there on your first fill in any car you don't know.
- Mark your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems daft. It does the trick.
- Mistakes like this are simple to make while your mind is on something else, and so your phone goes away.
- Add-on devices exist for vehicles without one, and some diesels come with a filler that will not accept a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- As soon as you notice, stop: less petrol inside that tank means a thinner mixture. What to do next doesn't change, though — still don't fire it up.
Gulval: already put petrol in a diesel?
Short and simple, then, is the order of things. Starting it is out, and so is switching on the ignition. The attendants on the forecourt — whether at Sainsbury's itself or wherever you filled up — will usually help push it clear of the petrol pump if you ask. Call 0333 366 0103 next, with three facts — your fuel, the approximate amount, and whether it has run.
If it was AdBlue instead of petrol, say so. That is a different issue — corrosion and deposits rather than lost protection — and it has its own page for Gulval.
One petrol in a diesel task in Gulval costs more than another. Why?
There is no honest single price for this, because the four situations above are four separate tasks. The situation itself does most of the work of moving your cost. Two things come after that: the petrol that got in as a share of what the tank takes, then the place the car is in and whether a technician can get to it safely.
That's why our technicians ask three queries before quoting instead of after: what was put in, how much, and if it has run. Those answers change a range into a straight figure.
About Gulval and its setting
Gulval is a small suburban area in Cornwall, situated near the coast at an elevation of around 33 metres. Gulval lies within a short distance of several nearby places, including Trevarrack, Chyandour, and Trythogga. Gulval has a population of approximately 1405 people, with semi-detached housing being the predominant type in the area. Gulval is located near the city of Truro, which is around 22.7 miles away.
Fuel drain cover around Gulval and across Cornwall
Gulval sits in the TR postcode area, and our vans that answer petrol in diesel call-outs there work the spots near it as well — Trevarrack, Chyandour and Trythogga among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and the car does not need to come to us.
At the petrol pump around Gulval, still?
No position is better: that is where you now are. Keep it off. Ring.