Petrol in a Diesel Car in Oakham: How Worried Should You Be?
Probably less than you are now — as long as no one has started the vehicle. Till the ignition primes the pump, your starter turns, or the vehicle is driven, petrol in a diesel tank just sits there and does nothing. Which makes the truthful reply to that first Oakham question — "have I ruined it?" — usually no. To leave the car that way, ring Petrol in Diesel and leave your motor switched off. The rest of this page explains what petrol really does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Inside the motor: what petrol in a diesel does
Diesel has two jobs on its way through a motor. Oiling comes before burning; it does both. The high-pressure pump and your injectors are made to extremely fine gaps, and your diesel passing through them is what stops those surfaces from grinding against each other.
Of these two jobs, petrol manages the first poorly and the second never. It is runnier than diesel and takes away the lubrication the fuel system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Put those together and the shape of the problem is plain. Not contact but movement is what causes the harm. Any tank with petrol in it is a fuel problem. After the pump has been running on that petrol, a mechanical fault has begun: anything shed by a pump that's wearing down travels onward to the injectors with your fuel.
Oakham, petrol in a diesel: four cases, from mild to significant
The best case there can be: filled up, not once started. Only your tank has petrol in it, so the job is clearing the tank and flushing the fuel system where the vehicle sits. This scenario can only really take place on a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a moment. With your system primed, your lines and filter now hold petrol that has come from your tank. Drain, flush, deal with the fuel filter: still normally easy.
A couple of miles driven, and the pump has spent each of them labouring on weakened fuel. How hard the vehicle was driven counts as much as how far, and this work takes in that tank, the lines, your filter and fresh fuel through the entire system. On the school run to Tividale Hall Primary School, the mileage is small. Very different once more: a trip to Wolverhampton, under 10 miles away, or any distance on the M5, under 3 miles from Oakham, where your engine kept running hard.
Driven until it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That is the engine telling you its fuel no longer is behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Oakham Road. Permanent damage is very rare if a car is stopped early, and the drain and flush-through that still come first deal with it.
Oakham people and that 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'll be." Topping up takes out nothing; it gives you a bigger tank of the same mix. The idea behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
Not so: a newer diesel copes with a bit of petrol. Rather, the reverse. A modern diesel runs its fuel through smaller components at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that catches people. Feed diesel to a petrol motor and it generally won't run, so the driver stops — and the harm stops with them. While your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running does not mean fine.
Myth: "Add some two-stroke oil and drive it home." It is an old workaround for a separate issue. It doesn't put back what petrol has thinned, and that petrol is still inside that tank later.
Once your engine has been run, part of the petrol sits in the fuel filter and the fuel lines, not the tank — and your next start pulls it right back through your pump. So the myth "drain that tank yourself and you're sorted" doesn't hold. It's also genuinely hazardous to drain petrol into a can at the roadside.
How does petrol in a diesel happen?
Carelessness is seldom the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle mostly won't go into a petrol car at all. So the mistake runs one way.
When routine and the vehicle stop matching, it occurs. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. Racing for a train at Dudley Port and filling up en route. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: precisely when it takes place. Add rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Oakham motorists: how to avoid petrol in a diesel next time
- The label is what matters, and so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- Many vehicles state the fuel inside the filler flap or on the cap, so check it on the first fill in any car you don't know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- It seems daft and it works: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- Mistakes like this are simple to make whilst your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop reading the petrol pump.
- The moment you notice, stop: less petrol in the tank means a thinner blend. What to do next doesn't change, though — still do not fire it up.
Put petrol in a diesel around Oakham already?
Then the order of things is brief. Starting it is out, and so is switching on the ignition. The staff on the forecourt — whether at the nearest petrol station itself or wherever you filled up — will usually help push it clear of the petrol pump if you ask. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run.
Corrosion and deposits form the problem with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Oakham page.
Why one petrol in a diesel task around Oakham costs more than another
The four scenarios above are four different tasks, so no single price for this would be fair. Which of them you are in is chiefly what shifts your cost. The share matters next, meaning how much of the tank is petrol, followed by the position of the vehicle and whether reaching it is safe for our van.
Three questions come first, before any quote, instead of after — what went in, how much, has it run — and that is the reason. The answers change a range into a straight figure.
About Oakham and where it is
Oakham is a suburban area in the West Midlands, situated near the River Tame and close to the city of Wolverhampton. Oakham occupies a riverside location at an elevation of around 233 metres, with nearby landmarks including Darbys Hill and Tividale Hall. Oakham has a population of approximately 4718 people, living in predominantly semi-detached housing.
Fuel drain cover across West Midlands, Oakham included
Our teams answering petrol in diesel jobs in Oakham, in the B postcode area, also work the spots near it, Darbys Hill, Tividale Hall and Cawney Hill among them. We drain wherever your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
In Oakham and still at the pump?
No position is better: that's where you now are. Keep the car switched off, then ring.