How Worried Should You Be? Petrol in a Diesel Car in Newton Mearns
Less than you probably are, if it hasn't been started. Petrol sitting in a diesel tank does nothing to the motor till something pulls it through the system — the ignition priming your pump, the starter, or driving on its own. So the honest answer to the first query anyone in Newton Mearns asks, "have I ruined it?", is generally no. Petrol in Diesel is who to phone, with the engine kept off, so it stays that way. The rest of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
The motor and petrol in a diesel: what happens
On its way through an engine, diesel has two tasks. It ignites, and before it ignites it protects. What stops the surfaces inside your high-pressure pump and the injectors from grinding against one another is your diesel flowing through them — they're built to extremely fine gaps.
Poorly at the first, not at all at the second: that is petrol. It's thinner than diesel and removes the protection the fuel system depends on, and so a pump running on a petrol blend 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 clattering comes from.
The shape of the trouble is plain when you put those together. It is movement that does the harm, not contact. A tank with petrol in it is a fuel problem. After the pump has been running on that petrol, a mechanical issue has started: anything shed by a pump that is grinding is carried downstream to the injectors with your fuel.
How bad is petrol in a diesel? Four scenarios we see in Newton Mearns
The best case there can be: filled up, never started. Only your tank has petrol in it, so the job is emptying the tank and rinsing the system where the car stands. This scenario can only really happen on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. Petrol has come out of the tank and reached your filter and your lines, because the fuel system has been bled. Still normally simple: drain, flush, and your filter dealt with.
Your pump has worked a few miles on diluted fuel — that is what driving it does. Distance is only half of it; how hard it was driven matters just as much. Either way the work runs to that tank, the lines, the filter and fresh fuel through the whole system. On the school run to the local primary school, the miles is short. Very different a second time: a trip to Glasgow, under 10 miles away, or any miles on the M77, under a mile from Newton Mearns, where your engine never stopped working hard.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The engine is telling you the fuel is no longer behaving like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Eaglesham Road. What comes first is still the fuel drain and flush-through, and that deals with it, with lasting damage very unusual when a car is pulled over quickly.
Petrol in a diesel stories Newton Mearns people hear
Myth: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. The assumption behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. Protection counts more on modern diesels, not less, because their fuel runs through more precise components at higher pressure.
"It starts, it drives, and so no harm done" — the myth that trips up most drivers than any other. Diesel in a petrol motor usually leaves a motor that will not run: the driver stops, and so does the harm. Feed petrol to a diesel and it generally starts, idles and pulls away as if nothing has happened — all while its pump wears. Being able to run is not proof of being fine.
An outdated fix for a separate issue is behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol diluted is put back by it — and later, your tank still holds the petrol.
Myth: "Drain the tank yourself and you're sorted." Once your engine has been run, some of that petrol is no longer in your tank: it is in the fuel filter and the lines, and it goes right back through your pump at your next start. Clearing petrol into a can at the roadside is also really hazardous.
How does petrol in a diesel take place?
Nobody does it on purpose, and it's seldom carelessness. A diesel nozzle mostly will not fit a petrol motor, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and just in that direction.
The moment routine stops matching your car is the moment it occurs. A motor that is new to you — a hire car, on loan as a courtesy car, or just bought. Two cars on one drive, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. Rushing for a train at Patterton and filling up en route. Exactly the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
How to prevent petrol in a diesel on your next fill-up in Newton Mearns
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on every forecourt. The label is what counts.
- Plenty of cars state the fuel type inside your filler flap or on the cap, so check it on the first fill in any motor you don't know.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key if a household has one of each. So label it.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new car, say "diesel" out loud. Daft, yes, but it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to reject a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol inside your tank means a thinner mixture. What to do next doesn't change, though — still don't start the car.
Put petrol in a diesel around Newton Mearns already?
The order of things is short, then. Do not fire it up, and do not turn the ignition on. If you're still on the forecourt — Esso or anywhere else — ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We'll ask what got in, about how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That's a different fault — corrosion and deposits instead of lost protection — and it has its own page for Newton Mearns.
What makes one Newton Mearns petrol in a diesel job cost more than the next
There's no fair single price for this, since the four scenarios above are four different tasks. Chiefly, the cost moves with which situation you are in. The proportion matters next, meaning how much of your tank is petrol, and then the position of your car and whether reaching it is safe for a technician.
Three questions come first, before quoting, rather than after — what got in, how much, has it run — and that is the reason. With those answers, you get a straight figure instead of a range.
About Newton Mearns itself
Newton Mearns is a locality situated on the banks of the River Cart in East Renfrewshire, with a mix of rural and suburban landscapes. Newton Mearns has a relatively low elevation of 139 metres and is located near several smaller communities, including Broom and Mearns. Newton Mearns is characterized by its predominantly detached housing stock and is close to the city of Glasgow, which is about 7 miles away. Newton Mearns is also relatively distant from London, at a distance of approximately 341 miles.
Newton Mearns and East Renfrewshire: where our fuel drain cover runs
Petrol in diesel calls in Newton Mearns — part of the G postcode area — go to teams that also cover the locations around it, Broom, Mearns and Burnhouse included. Our engineers drain where your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the petrol pump around Newton Mearns, right now?
Then you are in the best position there is. Keep it off. Ring.