How Worried Should You Be? Petrol in a Diesel Car in Glenfarg
Far less than you likely are, provided it has not been started. Everyone around Glenfarg begins with "have I ruined it?", and the fair answer is normally no: petrol resting inside that tank of a diesel stays harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to call, with the engine kept off, so it remains that way. 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.
What petrol in a diesel does to the motor
Passing through an engine, diesel is doing two jobs at once. Oiling comes before burning; it does both. Made to extremely fine clearances, the injectors and the pump rely on your diesel flowing through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that is petrol. It is runnier than diesel and strips away the lubrication the fuel system rests on, so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the clattering comes from.
The shape of the trouble is clear when you put those together. Contact doesn't do the damage — circulation does. Petrol in a tank is a fuel fault. Once the pump has been running on that petrol, a mechanical problem has begun: whatever is shed by a pump that's grinding travels downstream to the fuel injectors with your fuel.
Four situations our engineers see around Glenfarg: how bad is petrol in a diesel?
Filled but never started — the best it gets. The petrol is in your tank and just your tank, and the task is a drain and a flush where the vehicle sits. This is the one situation that can only truly occur on a forecourt, since anywhere else your car has been driven to get there.
A moment's running, or merely your ignition on. Once primed, the fuel system has pulled petrol out of the tank as far as the fuel filter and the lines. Still generally simple: drain, flush, and the fuel filter dealt with.
The pump has spent a few miles on thinned fuel — that is what driving it meant. The work is that tank, the fuel lines, the filter and clean fuel through the entire circuit, and how hard your car was driven matters as much as how far. On the school run to the local primary school, the mileage is small. Driving as far as Perth, under 10 miles away, makes a very different job — as does any distance on the M90, under a mile from Glenfarg, with the motor working hard the whole time.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The motor is telling you your fuel is no longer acting like diesel. Stop wherever you are — the verge on Greenbank Road, a lay-by, a side street — and leave it there. Lasting damage is very uncommon when a car is pulled over quickly, and the fuel drain and flush that still go first take care of it.
What Glenfarg drivers get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. That guidance supposes a diesel fuel system tolerates petrol by percentage. It does not.
Myth: a modern diesel copes with a bit of petrol. Rather, the reverse. More precise components and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication count more, not less.
The myth that catches people off guard: if it starts and drives, it must be unharmed. A petrol motor fed diesel generally will not run, and so the motorist stops and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Running isn't the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. It does not put back what petrol has diluted, and that petrol is still in the tank later.
The next start sends petrol back round your pump from your lines and the fuel filter, where some of that ends up once your engine has been run. That is why a DIY tank drain does not leave you sorted — a myth. On top of that, petrol emptied into a can by the road is genuinely dangerous.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally won't fit a petrol car, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error easy, and only in that direction.
It happens when routine and the car stop matching. A vehicle that's new to you — a hire car, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. A forecourt you know, but with its pumps laid out differently. Rushing for a train outside Perth and filling up en route. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it happens. The hand does what it has always done once you add rain, a phone call or a back seat full of children.
Next time you fill up in Glenfarg: avoiding petrol in a diesel
- The label is what counts, and so read the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- In a car you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of vehicles print the fuel type there.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a home has one of each. So mark it.
- It seems daft and it does the trick: 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 put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop reading the pump.
- Stop as soon as you notice. Less petrol inside your tank means a thinner mix. It doesn't change what to do next, which is still not to crank it.
Glenfarg: already put petrol in a diesel?
In that case, there is only a short order of things. Leave it unstarted, with the ignition off too. If you are still at the forecourt — Thames or anywhere else — ask the staff to help you push the car away from the petrol pump. Phone 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different fault — Glenfarg has a page just for it.
What makes one Glenfarg petrol in a diesel job cost more than the next
There is no fair single price for this, because the four situations above are four different jobs. The scenario itself does most of the work of moving your cost. Two things follow that: the petrol that got in as a share of what your tank takes, then the spot the vehicle is in and whether our van can reach it safely.
What got in, how much, and if it has run — three queries our technicians ask before costing, not after, for exactly that reason. The answers change a range into a straight figure.
About Glenfarg
Glenfarg is a small village situated on the banks of the River Farg in Perth and Kinross, with a mix of rural and residential areas at an elevation of around 147 metres. Glenfarg has a population of approximately 665 people, living in predominantly detached housing. Glenfarg is located near several other small settlements, including Duncrievie, Fordel, and Newton of Balcanquhal, and is about 8 miles from the city of Perth. Glenfarg enjoys a scenic riverside setting, with the surrounding countryside offering opportunities for outdoor activities.
Across Perth and Kinross and around Glenfarg: fuel drain cover
Petrol in diesel jobs in Glenfarg — part of the PH postcode area — go to teams that likewise cover the spots round it, Duncrievie, Fordel and Newton of Balcanquhal included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places we drain, and your vehicle doesn't need to move to us.
In Glenfarg and still at the petrol pump?
The best spot there is, then — that's where you are. Keep the car turned off, and ring.