Should You Worry? Petrol in a Diesel Car in Debden Green
Unstarted? Then less anxious than you probably are. Till your ignition primes the pump, your starter turns, or your car is driven, petrol in a diesel tank simply waits there and does no harm. Which means the truthful reply to that first Debden Green question — "have I ruined it?" — normally no. Petrol in Diesel is who to call, with your engine kept off, and so it remains that way. Further down, you will find what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the motor?
Passing through a motor, diesel is doing two jobs at once. Before it ignites, it lubricates — then it combusts. Made to very fine gaps, the fuel injectors and the pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that's petrol. The knocking comes from petrol being designed 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 the system hinges on, and any pump working on that mixture is wearing itself.
Put those together and the shape of the trouble is plain. Contact doesn't do the harm — circulation does. Any tank with petrol in it is a fuel problem. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to your injectors downstream.
Four scenarios our engineers see in Debden Green: how serious is petrol in a diesel?
Filled up, not once started. The best case there is. The petrol is in your tank and just that tank, and the task is a drain and a flush where the car sits. This is the one situation that can only really happen on a forecourt, because anywhere else your car has been driven to get there.
Ignition on, or started for a moment. The fuel system has been bled, so petrol has left the tank and got to the fuel filter and the lines. Usually little more than emptying, flushing and seeing to the fuel filter, so still simple.
A couple of miles driven, and the pump has spent every one of them running on thinned fuel. Tank, lines, filter, then clean fuel put through the whole system: that is this work, and the way your car was driven matters as much as the mileage. A school run to Hereward Primary School is one matter. A run as far as London, under 15 miles away, is a very different task. So is any miles on the M11, under 3 miles from Debden Green, where your engine has been working hard the whole time.
Rattling, a ragged idle, smoke, a throttle gone soft: driven until it complained. That is the motor telling you its fuel has stopped acting like diesel. Stop where you are — on the verge on Debden Road, at the kerb, down a side road — and don't move it again. The drain and flush-through still go first, and they deal with it: when a car is pulled over quickly, permanent damage is very rare.
What Debden Green people 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 comes out when you top up — that tank simply carries more of the same blend. That guidance assumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: a current diesel copes with a bit of petrol. Rather, the opposite. Lubrication counts more on current diesels, not less, because their fuel runs through finer components at higher pressure.
This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." The driver of a petrol engine fed diesel normally has no choice but to stop, since it will not run, and the harm stops there. Feed petrol to a diesel and it generally starts, ticks over and drives away as if nothing has happened — all the while its pump is wearing. Fine and running aren't the same thing.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another issue. That petrol is still inside that tank after that, and what it has weakened isn't put back.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol lies in your filter and lines, waiting to go right back through the pump on your next start. Also, a can of petrol filled at the roadside is genuinely hazardous.
How it happens: petrol in a diesel
Carelessness is rarely the cause, and no one means to do it. A diesel nozzle generally won't go into a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
It occurs when habit and the car stop matching. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. Filling up in a rush en route to Chingford, with a train to catch. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Tiguan for the first time. Add a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up in Debden Green: preventing petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is only a hint.
- Inspect the filler flap. Many motors state the fuel inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- Label the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It sounds daft. It does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so the phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and add-on devices are available for the rest. Count it as a backstop, and keep reading the pump.
- The moment you notice, stop: less petrol in your tank makes a weaker mix. What to do next does not change, though — still don't fire it up.
Petrol already in a diesel around Debden Green? Begin here
Then the order of things is brief. Do not turn your ignition on, and do not fire it up. If you're still at the forecourt — Esso or anywhere else — ask the attendants to help you roll it clear of the petrol pump. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it has been run.
If it was AdBlue and not petrol, say so. That's a separate fault — corrosion and deposits and not lost protection — and it has its own page for Debden Green.
Debden Green petrol in a diesel jobs: why one costs more than another
There is no honest single quote for this, because the four scenarios above are four separate tasks. Chiefly, your cost shifts with which one you're in. Beyond that it's the ratio — how much petrol got in against how much that tank takes — and then where the car is and whether our van can get to it safely.
Before any quote, not after, come three queries: your fuel that went in, its amount, and whether it has run. That is why. With the answers, you get a straight figure instead of a range.
About Debden Green, for a moment
Debden Green is a suburban area in Essex, situated approximately 13.9 miles northeast of central London. Debden Green sits at an elevation of around 62 metres, near the towns of Loughton and Theydon Bois. Debden Green is characterized by its predominantly terraced housing stock, reflecting the typical residential development patterns of the region. Debden Green remains a commuter-focused community, with many residents travelling to London for work.
Fuel drain cover in Debden Green and across Essex
Our vans answering petrol in diesel call-outs around Debden Green, in the IG postcode area, equally work the spots around it, Loughton, Piercing Hill and Theydon Bois included. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
In Debden Green and still at the petrol pump?
Then you're in the best place there is. Keep the vehicle switched off, then ring.