Tivoli: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, if it has not been started. Petrol sitting in a diesel tank does nothing to the engine until something draws it through your fuel system — the ignition priming the pump, the starter, or the drive itself. So the truthful answer to the first query everyone in Tivoli asks, "have I wrecked it?", is normally no. To leave the vehicle that way, ring Petrol in Diesel and leave your motor alone. The rest of this page sets out what petrol really 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
On its way through a motor, diesel has two tasks. It ignites, and before it ignites it lubricates. Extremely fine clearances go into the fuel injectors and the high-pressure fuel pump, and only your diesel flowing through stops those surfaces grinding together.
Badly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the knocking.
The shape of the problem is clear once you put those together. Contact does not do the damage — movement does. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds goes on, borne by your fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue starts.
Four situations our engineers see in Tivoli: how serious is petrol in a diesel?
Filled up, not once started. The best case there is. The petrol is in your tank and only the tank, and the task is a drain and a flush where the car sits. This is the one situation that can only really take place on a forecourt, because anywhere else your car has been driven to get there.
Started for a second, or only the ignition on. The fuel system has been bled, and so petrol has left the tank and got to the fuel filter and the fuel lines. Still normally straightforward: drain, flush, and the fuel filter dealt with.
Driven a few miles. Now your pump has spent these miles labouring on thinned fuel. How hard your car was driven counts as much as how far, and the work covers that tank, the fuel lines, the fuel filter and clean fuel through the whole circuit. On the school run to St James' Church of England Primary School, the mileage is short. Any distance on the M5, under 3 miles from Tivoli, means the motor working hard throughout, and a run to Gloucester, under 10 miles away, makes a very different job too.
Knocking, a ragged idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you your fuel is no longer behaving like diesel. Pull up where you are — on the verge on Princes Road, at the kerb, down a side road — and don't move it again. What comes first is still the fuel drain and flush-through, and that takes care of it, with permanent damage very rare when a vehicle is stopped soon.
Petrol in a diesel myths Tivoli motorists hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. A diesel fuel system does not accept petrol by percentage in the way that advice assumes.
Myth: a modern diesel copes with a bit of petrol. If anything, the reverse. Protection counts more on modern diesels, not less, because their fuel passes through more precise components at higher pressure.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel normally stops, since it will not run, and the damage stops there. While your pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running does not mean fine.
An old fix for a different issue lies behind this one. Myth: "Add some two-stroke oil and drive the car home." What petrol has diluted stays diluted, and that petrol remains inside your tank anyway.
The next start draws petrol back round your pump from your lines and your filter, where some of that sits once the engine has been run. That's why a DIY tank drain does not leave you sorted — a myth. Emptying petrol into a can at the roadside is also truly hazardous.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Seldom, if ever. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol vehicle. That's how the forecourt makes it straightforward.
When routine and your car stop matching, it takes place. Courtesy car, hire car, or a motor that is brand new. One petrol and one diesel on the driveway of the same household. Your normal forecourt, its pumps suddenly in a different order. Filling up in a rush en route to Cheltenham Spa, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. The hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up around Tivoli
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what matters.
- Plenty of cars state the fuel type inside your filler flap or on the cap, and so check there on your first fill in any car you do not know.
- One of each in the house? Mark the key to the diesel — a coloured fob, a sticker — because intending to remember is not enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new motor, say "diesel" aloud. Daft, perhaps, yet it works.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Add-on devices exist for cars without one, and some diesels are built with a filler that won't accept a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- As soon as you notice, stop: less petrol in that tank makes a weaker blend. What to do next does not change, though — still do not start it.
Put petrol in a diesel in Tivoli already?
Short and simple, then, is the order of things. Don't crank it, and do not turn the ignition on. If you are still at the forecourt — Texaco or anywhere else — ask the attendants to help you roll the car away from the pump. Next, 0333 366 0103. We'll ask what got in, about how much, and if it has been run.
Corrosion and deposits form the trouble with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Tivoli page.
One petrol in a diesel task in Tivoli costs more than another. Why?
There is no fair single price for this, because the four situations above are four different jobs. Which of them you're in is mostly what moves the cost. Where the vehicle is counts too, and whether a van can safely get to it, after the share of petrol to what that tank holds.
What went in, how much, and if it has run — three questions our engineers ask before costing, not after, for precisely that reason. A range becomes a straight figure once the replies are in.
About Tivoli
Tivoli is a suburban area in Gloucestershire, situated on the riverside near Gloucester. Tivoli sits at an elevation of 68 metres, with The Park and Montpellier nearby. Tivoli is characterized by its predominant housing type, which is flat, and is located close to other neighbourhoods such as Bournside.
Across Gloucestershire and around Tivoli: fuel drain cover
Petrol in diesel calls around Tivoli — part of the GL postcode area — go to teams that also cover the locations round it, The Park, Montpellier and Bournside included. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots we drain, and the vehicle doesn't need to come to us.
Still at the petrol pump in Tivoli?
Then you are in the best spot there is. Ring, and keep it turned off.