Bury St Edmunds: Petrol in a Diesel Car? How Worried to Be
If it has not been started, worry far less than you probably are. "Have I ruined it?" is the first question everyone around Bury St Edmunds asks, and the honest answer is normally no, because petrol left in a diesel tank harms nothing until it is dragged through the fuel system — by ignition priming, by your starter, or by being driven. Petrol in Diesel is who to call, with your engine left off, so it remains that way. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you never repeat it.
Inside the engine: what petrol in a diesel really does
On its way through an engine, diesel has two jobs. Before it burns, it protects — and then it ignites. Very fine gaps are built into your injectors and the high-pressure pump, and only your diesel running through stops their surfaces grinding together.
Of those two jobs, petrol handles the first badly and the second never. A pump working on a petrol mixture is wearing itself out, because petrol is thinner than diesel and strips out the protection the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where the clattering comes.
Put those together and the shape of the problem is plain. It is movement that causes the damage, not contact. Any tank with petrol in it is a fuel problem. The start of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors beyond it.
Four situations our technicians see around Bury St Edmunds: how serious is petrol in a diesel?
The best case there can be: filled up, not once started. That petrol is in that tank and just the tank, and the task is a drain and a flush where your car stands. This is the one situation that can only truly take place at a forecourt, because anywhere else the vehicle has been driven to get there.
Ignition on, or started for a moment. With the fuel system primed, the lines and filter already contain petrol that came from the tank. Still generally simple: drain, flush, and the filter sorted.
Your pump now worked a couple of miles on thinned fuel — that's what driving the car does. How hard your car was driven matters as much as how far, and this work covers that tank, the fuel lines, the fuel filter and fresh fuel through the entire circuit. Driving the children to Guildhall Feoffment Community Primary School is one sort of trip. Driving as far as Ely, under 25 miles away, makes a very different task — as does any distance on the M11, under 25 miles from Bury St Edmunds, with the motor running hard the whole time.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. The fuel isn't behaving like diesel any more, and your motor is telling you. Stop wherever you are — the verge on Brentgovel Street, a lay-by, a side street — and leave the car where it is. What comes first is still the fuel drain and flush-through, and that deals with it, with long-term damage very unusual when a vehicle is pulled over quickly.
Petrol in a diesel stories Bury St Edmunds people hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed when you top up — that tank simply carries more of the same blend. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance supposes.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." More precise parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, so the driver stops — and the harm stops with them. While your pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Fine and running aren't the same at all.
An old workaround for a different fault is behind this one. Myth: "Add some two-stroke oil and drive it home." That petrol is still in the tank afterwards, and whatever it has weakened isn't put back.
The next start sends petrol back round the pump from your lines and the filter, where some of that ends up after the motor has been run. That's why a DIY tank drain does not leave you sorted — a myth. It's also genuinely hazardous to drain petrol into a can at the kerbside.
Petrol in a diesel: how does it occur?
A careless moment is rarely the cause, and no one means to do it. One way only, since of the nozzles: the smaller petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol vehicle. That's how the forecourt makes it simple.
Routine and the vehicle falling out of step is when it happens. Courtesy car, hire car, or a car that's new. Two cars on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. A train to catch, and a rushed fill on the way to the nearest station. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it has always done.
Avoiding petrol in a diesel next time you fill up around Bury St Edmunds
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Trust the label on the petrol pump, not the colour.
- Inspect your filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on the first fill in any car you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a house with one of each.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new motor, say "diesel" aloud. Silly, perhaps, yet it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away and keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a thinner mix, and so stop as soon as you notice — while remembering that your next stage is unchanged. It is still not to start the car.
Put petrol in a diesel around Bury St Edmunds already?
Then the order of things is short. Starting it is out, and so is turning on the ignition. Ask the attendants to help you push it away from the pump if you are still at the forecourt, whether that's Tesco or somewhere else. Then call 0333 366 0103 and tell us what went in, roughly how much, and if it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate issue — Bury St Edmunds has a page all for it.
Bury St Edmunds petrol in a diesel tasks: why one costs more than another
The four situations above are four different jobs, so no single quote for this would be honest. Chiefly, your cost moves with which one you're in. Two things follow that: the petrol that got in as a proportion of what that tank holds, then the spot the car is in and whether our van can reach it safely.
What was put in, how much, and if it's run — three questions our technicians ask before costing, not after, for precisely that reason. With the answers, you get a straight figure rather than a range.
About Bury St Edmunds and where it is
Bury St Edmunds is a historic town situated in the valley of the River Lark in Suffolk, with a mix of old and new buildings, including many terraced houses. Bury St Edmunds sits at an elevation of 51 metres, close to the villages of Fornham St Martin and Westley. Bury St Edmunds is located near the city of Ely and is about 62 miles from London. Bury St Edmunds has a population of around 17,552 people and is a significant urban centre in the region.
Across Suffolk and around Bury St Edmunds: fuel drain cover
The vans answering petrol in diesel calls in Bury St Edmunds, in the IP postcode area, also work the places near it, Fornham St Martin, Colton and Westley among them. You need not move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Bury St Edmunds and still at the petrol pump?
The best place there is, then — that is where you are. Ring, and keep it switched off.