How Worried Should You Be? Petrol in a Diesel Car in Hornchurch
Provided it hasn't been started, worry less than you likely 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 the first Hornchurch question — "have I ruined it?" — usually no. Keep it like that: leave your engine off and ring Petrol in Diesel. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to keep it from happening a second time: that's the rest of this page.
Petrol in a diesel: what does it do to your engine?
Two jobs fall to diesel on its journey round a motor. It protects first, and after that does it burn. Made to very fine tolerances, the injectors and your pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
Petrol handles the first job poorly and the second not at all. A pump working on a petrol blend is wearing itself out, since petrol is thinner than diesel and takes away the protection your fuel system relies on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any rattling comes.
The shape of the issue is clear once you put those together. The damage is done by circulation, not by contact. Where the petrol is only inside that tank, it's a problem of fuel, nothing more. Once your pump has been working on that petrol, a mechanical fault has started: anything shed by a pump that's grinding travels downstream to your injectors with the fuel.
How serious is petrol in a diesel? Four scenarios our technicians see in Hornchurch
Fuelled but never started — as good as it gets. On a forecourt, and truly only there, the petrol is still confined to your tank — because anywhere else the car was driven to reach it. The job is draining and rinsing on the spot.
Started for a moment, or only the ignition on. With the fuel system primed, the lines and filter already contain petrol that came from that tank. That's normally still an easy job — a drain, a flush, and the fuel filter seen to.
Those few miles on the road meant your pump working on fuel weakened by petrol throughout. How hard your car was driven counts as much as how far, and this work takes in the tank, your lines, your filter and fresh fuel through the whole circuit. Driving the kids to Langtons Infant School & Nursery is one kind of trip. A run as far as London, under 15 miles away, is a very different task. So is any miles on the M25, under 3 miles from Hornchurch, where the motor has been labouring hard throughout.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven until it complained. What you are hearing is your motor reporting fuel that no longer behaves like diesel. Whether it's the verge on High Street, a lay-by or a side street, stop there then leave it. A vehicle pulled over early very seldom has lasting damage, as the fuel drain and the flush-through, which still come first, sort it out.
What Hornchurch drivers get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing comes out when you top up — the tank simply carries more of the same mixture. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Lubrication matters more on newer diesels, not less, since their fuel passes through finer parts at higher pressure.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. A petrol motor fed diesel generally won't run, so the motorist stops and the damage stops with them. Feed petrol to a diesel and it normally fires up, idles and drives away like nothing has happened — all while its pump is wearing. Being able to run is not the same as being fine.
Myth: a two-stroke additive lets you to drive home. It is an old fix, supposed for another issue. It doesn't put back what petrol has weakened, and that petrol is still in that tank later on.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the filter and lines, ready to go right back through your pump at the next start. On top of that, petrol cleared into a can by the road is genuinely risky.
Petrol in a diesel: how does it occur?
It's seldom carelessness, and nobody does it on purpose. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol vehicle at all. So the mistake runs one way.
Habit and your car getting out of step is when it occurs. A vehicle that is new to you — hired, on loan as a courtesy car, or just bought. Two vehicles on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Filling up in a rush en route to Emerson Park, with a train to catch. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is exactly the moment it occurs. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it has always done.
Hornchurch drivers: how to avoid petrol in a diesel next time
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what matters.
- Check your filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on the first fill in a car you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key when a house has one of each. So label it.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices exist for vehicles without one. They are a safety net, not a reason to stop reading the petrol pump.
- Less petrol means a thinner mixture, and so stop the moment you notice — while remembering that the next step is unchanged. It's still not to start it.
Put petrol in a diesel in Hornchurch already?
Short and simple, then, is the order of things. Don't start it, and do not turn your ignition on. If you're still at the forecourt — Texaco or anywhere else — ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
Corrosion and deposits are the issue with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Hornchurch page.
What makes one Hornchurch petrol in a diesel job cost more than the next
The four scenarios above are four separate jobs, so no single quote for this would be fair. Which of them you're in is chiefly what shifts the cost. Where your car is counts too, and whether a van can safely reach it, after the proportion of petrol to what your tank takes.
What was put in, how much, and if it's run — three questions our engineers ask before costing, not after, for precisely that reason. The replies turn a range into a straight figure.
About Hornchurch itself
Hornchurch is a locality in the London Borough of Havering, situated on the banks of the River Ingrebourne. Hornchurch has a relatively low elevation of 27 metres and is located approximately 15 miles from central London. Hornchurch is close to nearby places such as Upminster Bridge, Emerson Park, and Upminster, and is characterized by a high proportion of flat dwellings.
Hornchurch and Greater London: where our fuel drain cover runs
Hornchurch sits in the RM postcode area, and our vans that answer petrol in diesel call-outs there work the places near it as well — Upminster Bridge, Emerson Park and Upminster among them. We drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Hornchurch: still at the petrol pump?
Then you are in the best place there is. Keep it off. Ring.