How Worried Should You Be? Petrol in a Diesel Car in Summit
Unstarted? Then less anxious than you likely feel. Until your ignition primes the pump, your starter turns, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to the first Summit query — "have I ruined it?" — normally no. Leave your engine off then phone Petrol in Diesel — that is how you keep it that way. What petrol actually does to a diesel, how to judge how far it's gone, and how to keep it from happening a second time: that's the rest of this page.
Inside the engine: what petrol in a diesel really does
Two jobs fall to diesel on its route round a motor. Lubricating comes before burning; it does both. Very fine tolerances are built into your injectors and the high-pressure fuel pump, and just the diesel flowing through keeps those surfaces from grinding together.
The second job petrol does not do at all, and the first it does badly. It is thinner than diesel and removes the protection your fuel system hinges on, so a pump running on a petrol mixture 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 rattling comes from.
The shape of the problem is plain when you put those together. Contact does not do the harm — circulation does. Petrol in the tank 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 your fuel to the fuel injectors downstream.
Four situations we see around Summit: how serious is petrol in a diesel?
The best case there is: filled up, never started. That petrol is in that tank and only the tank, and the task is a drain and a flush where the vehicle stands. This is the one situation that can only truly happen on a forecourt, as anywhere else the vehicle has been driven to get there.
Started for a second, or only your ignition on. Petrol has come out of your tank and got to the fuel filter and the fuel lines, since the system has been primed. Still usually easy: drain, flush, and your filter sorted.
Those few miles on the road meant your pump working on fuel weakened by petrol the whole way. Miles is only half of it; how hard it was driven matters equally. Either way the work runs to the tank, your lines, the fuel filter and fresh fuel through the entire circuit. Driving the kids to Thornham St. James CofE Primary School is one sort of trip. Any distance on the M62, under a mile from Summit, means the engine working hard throughout, and a run to Manchester, under 10 miles away, makes a very different task too.
Driven until it complained. Rattling, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Lowther Avenue. What goes first is still the drain and flush, and that sorts it out, with permanent damage very unusual if a car is pulled over soon.
What Summit people get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a fuller tank of the same mix. A diesel fuel system does not tolerate petrol by percentage in the way that advice presumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through finer components: that's how a newer diesel moves its fuel, and so the protection matters for more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up more motorists than any other. Feed diesel to a petrol motor and it usually will not run, so the driver stops — and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump wears. Running isn't the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate fault. The petrol is still in your tank after that, and what it has thinned isn't put back.
If your engine has run, part of that petrol is in the filter and your lines, not your tank — and your next start pulls it right back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. Besides, petrol drained into a can by the road is genuinely risky.
How does petrol in a diesel happen?
It's seldom carelessness, and nobody does it on purpose. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it simple, and the mistake runs one way.
When habit and the car stop matching, it occurs. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A well-known forecourt with the pumps in a different order. Rushing for a train at Castleton and fuelling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a driver used to petrol: exactly when it takes place. Your hand does what it has always done when you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up around Summit
- The label is what counts, so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- Many vehicles state the fuel inside your filler flap or on the cap, so check there on your first fill in any motor you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key if a house has one of each. So label it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems daft and it does the trick.
- Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away.
- Some diesels have a filler designed to refuse a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Noticing it mid-fill? Stop there and then. A thinner mix results from less petrol inside your tank, but the next stage remains the same: do not fire it up.
Petrol already in a diesel around Summit? Begin here
In that case, there's just a short order of things. Don't start the car, and do not switch the ignition on. Ask the attendants to help you push it clear of the pump if you're still at the forecourt, whether that's Texaco or anywhere else. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it has been run.
Say so if it was AdBlue rather than petrol: it's a separate fault, with its own page for Summit, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel task in Summit costs more than another. Why?
Four separate jobs lie behind the four situations above — which is why there's no honest single quote. Which of them you're in is mostly what moves your cost. The ratio counts next, meaning how much of the tank is petrol, and then the position of the vehicle and whether getting to it is safe for a van.
Three queries come first, before any quote, instead of after — what got in, how much, has it run — and this is the reason. The answers turn a range into a straight figure.
About Summit and where it is
Summit is a suburban area in Greater Manchester, situated near the River Mersey and close to several local landmarks, including Hanging Chadder and Gravel Hole. Summit sits at an elevation of 205 metres, with semi-detached housing being the predominant type of accommodation in the area. Summit is located approximately 8.4 miles from Manchester, making it a commuter-friendly location for those working in the city.
Fuel drain cover in Summit and across Greater Manchester
Summit waits in the OL postcode area, and the vans that answer petrol in diesel jobs there work the places near it as well — Hanging Chadder, Gravel Hole and Narrow Gate Brow among them. You need not move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
In Summit and still at the petrol pump?
The best position there is, then — that's where you are. Keep the vehicle turned off, then ring.