Petrol in a Diesel Car in Stanley: How Worried Should You Be?
If it hasn't been started, worry far less than you likely are. Petrol resting in a diesel tank does nothing to your engine until something pulls it through the fuel system — the ignition priming your pump, the starter, or the drive on its own. So the truthful answer to the first question everyone around Stanley asks, "have I wrecked it?", is usually no. Leave your motor off then call Petrol in Diesel — that keeps it that way. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to the engine
Diesel does two jobs on its way through an engine. Before it ignites, it protects — then it burns. The high-pressure pump and the injectors are built to very fine clearances, and the diesel passing through them is what keeps those surfaces from grinding against each other.
The second task petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the lubrication your system depends on, and any pump working on such a blend is wearing itself.
Together, those leave the shape of the problem plain. Not contact but circulation is what does the damage. All a tank with petrol in it amounts to is a fuel issue. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the injectors further on.
Four situations our technicians see around Stanley: how bad is petrol in a diesel?
Fuelled, and not started: nothing beats it. That petrol is inside the tank and only that tank, and the task is a drain and a flush where the vehicle sits. This is the one scenario that can only truly occur at a forecourt, since anywhere else the vehicle has been driven to get there.
Your ignition turned on, or a brief start. Petrol has left the tank and got to the fuel filter and the fuel lines, because the fuel system has been bled. Still generally simple: drain, flush, and the fuel filter dealt with.
Driven a few miles. Now your pump has spent these miles working on weakened fuel. Distance is only half of that; how hard it was driven counts just as much. Either way the work includes your tank, the fuel lines, your filter and fresh fuel through the whole circuit. Short trips, like the school run to the local primary school, are one thing. Very different a second time: a trip to Perth, under 10 miles away, or some distance on the M90, under 10 miles from Stanley, where your engine never stopped working hard.
Knocking, an uneven idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you your fuel is no longer acting like diesel. Whether it is the verge on West Park, a lay-by or a side road, stop there and leave it. Lasting damage is very rare if a car is pulled over quickly, and the fuel drain and flush that still come first sort it out.
Stanley drivers and the petrol in a diesel stories they hear
Myth: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mixture is all you get, since topping up takes out nothing. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." A current diesel sends its fuel through smaller components at higher pressure, which makes the protection matter more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no damage done." The motorist of a petrol engine fed diesel usually stops, since it will not run, and the damage stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Being able to run isn't proof of being fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, supposed for another fault. The petrol is still in the tank after that, and what it has diluted isn't put back.
Once the engine has run, part of that petrol sits in the fuel filter and the fuel lines, not that tank — and the next start pulls it right back through the pump. So the myth "drain that tank yourself and you are sorted" does not stand up. Clearing petrol into a can by the roadside is also genuinely dangerous.
How does petrol in a diesel occur?
Nobody does it on purpose, and it is seldom carelessness. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it simple, and the mistake runs one way.
Habit and the car getting out of step is how it happens. A new vehicle, a hire car or a courtesy car. Two cars on one driveway, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. Fuelling up in a rush en route to Perth, with a train to catch. A new-to-you diesel BMW 3 Series, its first fuelling, and a driver accustomed to petrol: precisely when it occurs. The hand does what it has always done once you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up around Stanley
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on every forecourt. The label is what counts.
- Check the filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, for a home with one of each.
- It sounds daft and it works: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away and keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop checking the pump.
- Noticing it mid-fill? Stop there and then. A weaker mix follows from less petrol in that tank, yet your next step remains the same: don't fire it up.
Stanley: already put petrol in a diesel?
Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. The staff on the forecourt — whether at Gulf itself or wherever you filled up — will usually help push it away from the pump if you ask. What went in, about how much, and if it's run: tell us that when you ring 0333 366 0103.
If it was AdBlue and not petrol, say so. That's a different problem — corrosion and deposits and not lost lubrication — and it has its own page for Stanley.
One petrol in a diesel job around Stanley costs more than another. Why?
The four situations above are four different jobs, so no single quote for this would be fair. What moves the cost is mostly which of them you're in. Two things come after that: the petrol that went in as a share of what the tank takes, then the place the vehicle is in and whether a technician can reach it safely.
Ahead of any quote, not after, come three questions: your fuel that got in, its amount, and whether it's run. That is why. Their answers are what turn a range into one firm number.
About Stanley and where it is
Stanley is a village situated on the riverside in Perth and Kinross, with a relatively low elevation of around 60 metres. Stanley sits near the city of Perth, approximately 5.9 miles away, and is close to other nearby places such as West Tofts and Airntully. Stanley has a population of around 1379 people and predominantly features detached housing. Stanley is located in a scenic area, with the River Tay flowing nearby.
Fuel drain cover across Perth and Kinross, Stanley included
Stanley waits in the PH postcode area, and the vans that answer petrol in diesel calls there work the places near it as well — West Tofts, Airntully and Guildtown among them. The car doesn't need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Stanley: still at the pump?
The best position there is, then — that's where you are. Keep it off. Call.