Penprysg: Petrol in a Diesel Car? How Worried to Be
Provided it hasn't been started, you can worry less than you likely are. Everyone around Penprysg starts with "have I wrecked it?", and the honest answer is generally no: petrol resting in that tank of a diesel remains harmless until priming, cranking or driving pulls it into the system. To keep the vehicle that way, ring Petrol in Diesel then leave the motor switched off. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you never repeat it.
Inside the motor: what petrol in a diesel really does
Two jobs fall to diesel on its route round a motor. It protects first, and after that does it burn. Extremely fine clearances are built into your injectors and the high-pressure pump, and just your diesel running through keeps their surfaces from grinding together.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on the mixture wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
Combined, those leave the shape of the problem plain. Not contact but circulation is what does the damage. Where that petrol is only in the tank, it is a problem of fuel, nothing more. Once your pump has been working on that petrol, a mechanical issue has begun: whatever is shed by a pump that is wearing travels downstream to the injectors with the fuel.
Penprysg, petrol in a diesel: four cases, from mild to serious
Filled but not once started — the best it gets. At a forecourt, and truly only there, the petrol is still confined to your tank — since anywhere else the car was driven to get to it. The task is emptying and rinsing on the spot.
Ignition on, or started for a second. Petrol has left your tank and got to the fuel filter and your lines, since the system has been bled. That's normally still an easy task — a drain, a flush, and your filter seen to.
A few miles driven, and the pump has spent every one of them labouring on diluted fuel. Tank, lines, filter, then fresh fuel put through the whole system: that's the work, and the way the car was driven matters as much as the mileage. Short trips, such as the school run to the local primary school, are one matter. Getting as far as Cardiff, under 15 miles away, makes a very different task — as does any miles on the M4, under a mile from Penprysg, with the engine working hard all the way.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your engine signalling fuel that no longer runs like diesel. Whether it is the verge on Islawen Meadows, a lay-by or a side street, stop where you are and leave it. What comes first is still the drain and flush-through, and that deals with it, with permanent damage very unusual if a vehicle is stopped quickly.
Petrol in a diesel myths Penprysg motorists hear
Myth: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That advice presumes a diesel fuel system handles petrol by percentage. It doesn't.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Protection matters more on current diesels, not less, because their fuel runs through more precise parts at higher pressure.
This is the one that fools motorists. Myth: "If it starts and drives, there is no damage done." Diesel in a petrol motor normally means a motor that won't run: the driver stops, and so does the damage. Whilst the pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate problem. What petrol has weakened stays thinned, and that petrol remains in your tank anyway.
Once the motor has run, part of that petrol sits in the filter and your lines, not that tank — and your next start pulls it right back through the pump. So the myth "drain your tank yourself and you're sorted" does not hold. It is also truly hazardous to drain petrol into a can by the kerbside.
How it happens: petrol in a diesel
Carelessness is rarely the cause, and nobody means to do it. A diesel nozzle generally will not go into a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and just in one direction.
The moment habit stops matching your car is the moment it occurs. Courtesy car, hire car, or a motor that is brand new. One petrol and one diesel on the driveway of the same household. A forecourt you know, only with its pumps laid out differently. A rushed fill on the way to Pencoed with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. Add rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
How to prevent petrol in a diesel on your next fill-up around Penprysg
- The label is what matters, and so read the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- The first fill in an unfamiliar motor is the time to check the filler flap — on it, or on the cap, plenty of vehicles state which fuel they take.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a house with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It seems silly and it does the trick.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices exist for cars without one, and some diesels are built with a filler that won't accept a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Less petrol makes a weaker mix, so stop the moment you notice — while remembering that the next step is unchanged. It is still not to fire it up.
Penprysg: already put petrol in a diesel?
Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. Still at the forecourt, at Texaco or anywhere else? Ask the attendants to help you push the vehicle clear of the pump. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate fault — Penprysg has a page just for it.
Penprysg petrol in a diesel jobs: why one costs more than another
There is no fair single price for this, because the four scenarios above are four separate tasks. The scenario itself does most of the work of moving the cost. The proportion counts next, meaning how much of your tank is petrol, and then the location of the vehicle and whether reaching it is safe for a technician.
Ahead of any quote, not after, come three queries: your fuel that got in, the volume, and if it has run. That's why. The replies change a range into a straight figure.
About Penprysg, for a moment
Penprysg is a suburban area in Bridgend, situated on the riverside at an elevation of 65 metres, with semi-detached housing being the predominant type of accommodation. Penprysg lies near the communities of Pencoed, Felindre, and Brynnau Gwynion, and is approximately 14 miles from Cardiff. Penprysg has a population of around 2686 residents, and is located in a region with easy access to the nearby city. Penprysg is also within commuting distance of major cities, with London being around 145 miles away.
Fuel drain cover across Bridgend, Penprysg included
Our teams answering petrol in diesel calls around Penprysg, in the CF postcode area, equally work the spots near it, Pencoed, Felindre and Brynnau Gwynion included. The car doesn't need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the pump in Penprysg?
No position is better: that's where you are. Turned off it stays; then phone.