Petrol in a Diesel Car in Lower Cam: How Worried Should You Be?
Unstarted? Then less worried than you probably are. Everyone around Lower Cam begins with "have I ruined it?", and the honest answer is generally no: petrol left inside the tank of any diesel stays harmless till priming, cranking or driving draws it into the system. Keep it like that: leave the motor off then phone Petrol in Diesel. The remainder of this page covers what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Petrol in a diesel: what does it do to your engine?
On its way through an engine, diesel has two jobs. It lubricates to begin with, and after that does it burn. Built to very fine gaps, the fuel injectors and your pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
Of those two jobs, petrol handles the first poorly and the second never. It is thinner than diesel and takes away the protection your fuel system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
The shape of the issue is clear when you put those together. It is circulation that does the harm, not contact. A tank with petrol in it is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Petrol in a diesel in Lower Cam: how bad is it? Four cases
Fuelled but not once started — as good as it gets. At a forecourt, and genuinely only there, that petrol is still limited to your tank — since everywhere else the car was driven to get to it. The job is emptying and purging on the spot.
Ignition on, or started for a second. The fuel system has been bled, so petrol has left your tank and reached the filter and your lines. That's generally still an easy job — a drain, a flush, and your filter seen to.
Your pump has worked a couple of miles on thinned fuel — that is what driving it meant. Miles is only half of that; how hard it was driven counts just as much. Either way this work runs to your tank, the fuel lines, your filter and fresh fuel through the entire circuit. Short trips, such as the school run to Cam Hopton Church of England Primary School, are one thing. Driving as far as Gloucester, under 15 miles away, makes a very different job — as does any mileage on the M5, under a mile from Lower Cam, with the motor labouring hard all the way.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and your engine is telling you. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Chapel Street. A car stopped early very rarely has lasting damage, because the drain and the flush-through, which still come first, take care of it.
Lower Cam motorists and the petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing comes out when you top up — that tank just holds more of the same blend. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a current diesel copes with a bit of petrol. Rather, the reverse. More precise parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, and so no harm done" — the myth that catches more people than any other. A petrol motor fed diesel usually won't run, and so the driver stops and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump wears. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, supposed for another issue. It doesn't put back what petrol has weakened, and the petrol is still in that tank afterwards.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in your filter and lines, waiting to go straight back through your pump on your next start. Draining petrol into a can at the roadside is also really dangerous.
How does petrol in a diesel take place?
Nobody does it on purpose, and it's seldom carelessness. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol motor. That is how the forecourt makes it straightforward.
It happens when routine and your car stop matching. Hire cars, courtesy cars, and vehicles that are new to you. Two cars on one drive, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Rushing for a train at Cam & Dursley and fuelling up en route. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is exactly the moment it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel on your next fill-up around Lower Cam
- Green for unleaded and black for diesel is usual in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- Many vehicles state the fuel type inside your filler flap or on the cap, so check there on the first fill in any motor you don't know.
- One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- It sounds silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to reject a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a backstop, then keep reading the petrol pump.
- Stop as soon as you realise. Less petrol in that tank makes a thinner mix. It does not change what to do next, which is still not to crank it.
Lower Cam: already put petrol in a diesel?
The order of things is short, then. Do not crank it, and don't turn your ignition on. If you're still at the forecourt — Shell or anywhere else — ask the staff to help you push the car away from the pump. Phone 0333 366 0103 next, with three facts — your fuel, the rough amount, and whether it has run.
If it was AdBlue and not petrol, say so. That is a different problem — corrosion and deposits instead of lost lubrication — and it has its own page for Lower Cam.
One petrol in a diesel job around Lower Cam costs more than another. Why?
There is no fair single quote for this, since the four scenarios above are four different tasks. Mostly, your cost shifts with which one you are in. Beyond that it's the proportion — how much petrol went in against how much the tank takes — and then where your car is and whether a technician can get to it safely.
Three queries come first, before any quote, instead of after — what got in, how much, has it run — and that is the reason. With those replies, you get a straight figure instead of a range.
About Lower Cam
Lower Cam is a suburban area situated on the banks of the River Cam, with a mix of semi-detached housing and other residential properties. Lower Cam benefits from its proximity to Gloucester, being around 12 miles from the city centre, and is also relatively close to other nearby places such as Fairmead and Summerhayes. Lower Cam has a population of approximately 3569 people and is located at an elevation of 63 metres above sea level. Lower Cam is connected to the wider region by its road links, including those leading to London, which is around 97 miles away.
Fuel drain cover around Lower Cam and across Gloucestershire
Fairmead, Summerhayes and Cam are among the spots near Lower Cam that the same vans work, answering petrol in diesel calls across Lower Cam's GL postcode area. The car doesn't need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the pump around Lower Cam, right now?
In that case, you couldn't be in a better place. Leave the car switched off, and ring.