Middle Herrington: Petrol in a Diesel Car? How Worried to Be
Not started? Then less worried than you likely are. Until your ignition primes the pump, your starter cranks, or your vehicle is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the honest reply to that first Middle Herrington question — "have I ruined it?" — usually no. To leave the car that way, ring Petrol in Diesel then leave your engine switched off. What petrol actually does to a diesel, how to judge how far it has travelled, and how to stop it from happening a second time: that's the rest of this page.
Your engine and petrol in a diesel: what happens
Two tasks fall to diesel on its journey through a motor. It protects first, and after that does it burn. Very fine clearances are built into the fuel injectors and the high-pressure fuel pump, and just your diesel flowing through stops their surfaces grinding together.
Badly at the first, not at all at the second: that's petrol. It is thinner than diesel and takes away the protection your fuel system depends on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the clattering comes from.
Combined, those leave the shape of the problem plain. It's circulation that does the damage, not contact. Where that petrol is only inside the tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds goes on, carried by your fuel, into the injectors further along, which is why a pump that has been working on the petrol is where a mechanical fault begins.
Four situations we see around Middle Herrington: how bad is petrol in a diesel?
Filled but not once started — the best it gets. The petrol is in the tank and just the tank, and the job is a drain and a flush where your car stands. This is the one situation that can only really happen at a forecourt, because anywhere else the car has been driven to get there.
Ignition on, or started for a second. Once primed, the fuel system has drawn petrol out of the tank as far as the fuel filter and the lines. Still usually simple: drain, flush, and the filter sorted.
A couple of miles driven, and the pump has spent each of them labouring on weakened fuel. Miles is only half of it; how hard it was driven counts just as much. Either way this work includes the tank, the fuel lines, the filter and fresh fuel through the whole circuit. On the school run to East Herrington Primary Academy, the miles is small. Driving as far as Sunderland, under 5 miles away, makes a very different job — as does any mileage on the A1(M), under 5 miles from Middle Herrington, with the motor working hard the whole time.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. That's the motor telling you its fuel has stopped behaving like diesel. Stop where you are — on the verge on Foxcover Lane, at the kerb, down a side road — and don't move it again. What goes first is still the fuel drain and flush, and that sorts it out, with permanent damage very unusual if a car is stopped soon.
Middle Herrington people and the petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up removes nothing; it gives you a fuller tank of the same mixture. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. A current diesel sends its fuel through smaller parts at higher pressure, which makes the lubrication count more, not less.
"It starts, it drives, so no harm done" — the myth that trips up more people than any other. Feed diesel to a petrol engine and it generally won't run, so the motorist stops — and the damage stops with them. While your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. A running engine doesn't mean fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another fault. It does not put back what petrol has diluted, and that petrol is still in that tank afterwards.
The next start sends petrol back round your pump out of your lines and the fuel filter, where some of that ends up after the engine has been run. That is why a DIY tank drain does not sort it — a myth. Emptying petrol into a can at the kerbside is also genuinely hazardous.
How does petrol in a diesel happen?
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol vehicle at all. So the slip runs one way.
When habit and your car stop matching, it occurs. A new motor, a hire car or a courtesy car. Two cars on one drive, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill on the way to Sunderland. A new-to-you diesel Skoda Octavia, its first fuelling, and a driver accustomed to petrol: precisely when it happens. With rain, a call arriving, or a car full of children to deal with, your hand just does what it always has.
How to prevent petrol in a diesel at your next fill-up in Middle Herrington
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Check the pump's label; the colour is only a clue.
- Plenty of vehicles state the fuel type inside the filler flap or on the cap, so check there on your first fill in any car you do not know.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key when a home 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 petrol pump. It seems daft and it does the trick.
- Tuck the phone away. This is an easy mistake to make while you are thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and add-on devices are available for the rest. Treat it as a backstop, then keep checking the pump.
- Less petrol makes a weaker blend, so stop as soon as you realise — while remembering that your next step is unchanged. It is still not to crank it.
Petrol already in a diesel in Middle Herrington? Start here
Then the order of things is short. Starting it is out, and so is switching on your ignition. Ask the staff to help you roll it away from the petrol pump if you're still on the forecourt, whether that is JET or somewhere else. Then call 0333 366 0103 and tell us what got in, about how much, and if it's run.
Corrosion and deposits are the issue with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Middle Herrington page.
What makes one Middle Herrington petrol in a diesel job cost more than the next
The four situations above are four different jobs, so no single price for this would be fair. What moves your cost is chiefly which of them you're in. The ratio matters next, meaning how much of your tank is petrol, followed by the location of the car and whether getting to it is safe for a van.
Three questions come first, before any quote, rather than after — what got in, how much, has it run — and this is the reason. A range turns into a straight figure once those replies are in.
About Middle Herrington, for a moment
Middle Herrington is a suburban area located inland in Tyne and Wear, approximately 3.1 miles from Sunderland and 85 metres above sea level. Middle Herrington sits near several other residential areas, including East Herrington, Doxford Park, and Thorney Close. Middle Herrington has a population of around 3047 people and is characterised by semi-detached housing. Middle Herrington is situated in the North East region of England, about 238.8 miles from London.
Across Tyne and Wear and around Middle Herrington: fuel drain cover
Petrol in diesel jobs in Middle Herrington — part of the SR postcode area — go to teams that likewise cover the locations around it, East Herrington, Doxford Park and Thorney Close included. The vehicle doesn't need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Middle Herrington and still at the pump?
The best spot there is, then — that's where you are. Keep it off. Ring.