Ferryside: Petrol in a Diesel Car? How Worried to Be
If it hasn't been started, you can worry less than you probably are. Until your ignition primes the pump, your starter turns, or your car is driven, petrol in a diesel tank just sits there and does nothing. Which means the honest reply to the first Ferryside question — "have I wrecked it?" — usually no. Keep it that way: leave your engine off then call Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and the way to make sure you don't repeat it.
What petrol in a diesel does to the motor
Two jobs fall to diesel on its route through a motor. It lubricates first, and after that does it burn. Made to extremely fine clearances, the injectors and your pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Petrol does the first task badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump running on the blend wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the rattling.
Put those together and the shape of the problem is clear. Not contact but circulation is what does the harm. Where the petrol is only inside the tank, it is a fault of fuel, nothing more. 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 the fuel to the injectors further on.
Ferryside, petrol in a diesel: four situations, from mild to major
Fuelled, and never started: no case is better. At a forecourt, and genuinely only there, the petrol is still limited to that tank — since anywhere else the vehicle was driven to get to it. The task is draining and flushing on the spot.
Started for a second, or only your ignition on. Petrol has come out of your tank and got to your filter and your lines, since the fuel system has been bled. Still generally easy: drain, flush, and the filter sorted.
Those few miles driven meant your pump labouring on fuel weakened by petrol throughout. How hard your car was driven counts as much as how far, and this work takes in that tank, the lines, the filter and fresh fuel through the whole circuit. On the school run to the local primary school, the miles is short. Any miles on the M4, under 15 miles from Ferryside, means the engine working hard throughout, and a run to Swansea, under 25 miles away, is a very different job too.
Driven until it complained. Rattling, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is the engine signalling fuel that no longer acts like diesel. Whether it's the verge on Water Street, a lay-by or a side street, stop where you are then leave it. A vehicle stopped soon very seldom has permanent damage, because the drain and the flush, which still go first, sort it out.
Stories Ferryside people hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A fuller tank of the same mix is all you get, since topping up removes nothing. Percentage is not how a diesel fuel system tolerates petrol, however much that advice assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Protection matters more on newer diesels, not less, since their fuel runs through smaller parts at higher pressure.
This is the one that fools people. Myth: "If it starts and drives, there's no damage done." Any petrol engine fed diesel usually will not run, and so the motorist stops and the damage stops with them. While the pump grinds, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Running is not the same as fine.
An outdated workaround for a different problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol thinned gets put back by it — and afterwards, that tank still holds the petrol.
If your engine has run, part of that petrol sits in your filter and your lines, not your tank — and your next start sends it right back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. It is also truly hazardous to drain petrol into a can at the kerbside.
Petrol in a diesel: how does it happen?
A careless moment is rarely the cause, and no one means to do it. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol motor at all. The forecourt makes it easy, and the mistake runs one way.
When routine and the car stop matching, it occurs. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A familiar forecourt with the pumps in a different order. A hurried fill on the way to the nearest station with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Throw in a back seat full of children, a phone call or rain, and the hand takes over.
Next time you fill up in Ferryside: preventing petrol in a diesel
- The label is what counts, so read the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Check your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, in a home with one of each.
- 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 sounds silly and it works.
- Mistakes like this are easy to make while your mind is on something else, and so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to reject a petrol nozzle, and add-on devices exist for the remainder. Treat it as a safety net, and keep reading the petrol pump.
- The moment you realise, stop: less petrol inside your tank means a weaker mix. What to do next does not change, though — still do not start it.
Put petrol in a diesel around Ferryside already?
Then the order of things is short. Leave it unstarted, with the ignition off as well. Still on the forecourt, at Murco or anywhere else? Ask the attendants to help you roll it clear of the petrol pump. What went in, about how much, and whether it's run: tell us those when you ring 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate issue — Ferryside has a page all for it.
Why one petrol in a diesel job in Ferryside costs more than another
Four different jobs lie behind the four situations above — which is why there is no honest single price. What shifts your cost is mostly which of them you are in. Beyond that it's the share — how much petrol was put in against how much your tank holds — and after that where the car is and whether a van can get to it safely.
That is why we ask three questions before quoting rather than after: what got in, how much, and if it has run. Those answers change a range into a straight figure.
About Ferryside itself
Ferryside is a small coastal village in Carmarthenshire, situated near the mouth of the Tywi estuary. Ferryside has a low elevation of around 12 metres above sea level and is located near the villages of Llansteffan and St Ishmael. Ferryside is characterized by its detached housing and is approximately 21 miles from the city of Swansea. Ferryside is a quiet residential community with a population of around 527 people.
Across Carmarthenshire and around Ferryside: fuel drain cover
Petrol in diesel jobs in Ferryside — part of the SA postcode area — go to vans that also cover the locations round it, Broadlay, Llansteffan and St Ishmael included. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations where we work.
At the pump around Ferryside, still?
Then you are in the best position there is. Keep it off. Ring.