Talgarth: Petrol in a Diesel Car? How Worried to Be
Provided it has not been started, worry less than you probably are. Till your ignition primes your pump, your starter turns, or the car is driven, petrol in a diesel tank just sits there and does no harm. Which makes the truthful reply to the first Talgarth question — "have I ruined it?" — normally no. To leave the car like that, phone Petrol in Diesel and leave your motor alone. Below, you will find what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the motor?
Two jobs fall to diesel on its journey round a motor. It lubricates first, and only then does it burn. Made to extremely fine clearances, your injectors and your pump depend on the diesel flowing through them to keep their surfaces from wearing against one another.
Petrol does the first job badly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump on the blend wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
Combined, those make the shape of the problem plain. It's movement that causes the harm, not contact. A tank with petrol in it is a fuel issue. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
How bad is petrol in a diesel? Four situations we see in Talgarth
Fuelled but not once started — the best it gets. At a forecourt, and really only there, the petrol is still limited to the tank — because everywhere else your car was driven to reach it. The task is emptying and flushing on the spot.
A brief spell of running, or merely the ignition on. The system has been bled, so petrol has left the tank and reached the fuel filter and your lines. Drain, flush, see to the fuel filter: still usually easy.
Those few miles on the road meant your pump labouring on fuel diluted by petrol the whole way. The work is that tank, your lines, the fuel filter and fresh fuel through the whole system, and how hard the vehicle was driven counts as much as how far. Driving the kids to the local primary school is one sort of trip. Any miles on the M4, under 50 miles from Talgarth, means your engine has worked hard throughout, and a run to Hereford, under 25 miles away, makes a very different job as well.
Driven on till it protested — clattering, smoke, a lumpy idle, a soft throttle. What you are hearing is the motor signalling fuel that no longer runs like diesel. Stop where you are — on the verge on Bell Street, at the kerb, down a side road — and do not move it. Permanent damage is very uncommon when a vehicle is stopped quickly, and the fuel drain and flush that still go first take care of it.
Stories Talgarth drivers hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing comes out when you top up — your tank simply carries more of the same mixture. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. Protection counts more on modern diesels, not less, because their fuel runs through finer parts at higher pressure.
This is the one that catches drivers. Myth: "If it starts and drives, there is no damage done." Any petrol motor fed diesel generally won't run, and so the motorist stops and the damage stops with them. Feed petrol to a diesel and it usually starts, idles and drives away like nothing happened — all the while its pump is wearing. Being able to run is not proof of being fine.
Not so: a two-stroke additive lets you to drive home. It was an old workaround, meant for another fault. It does not put back what petrol has thinned, and the petrol is still in the tank after that.
The next start draws petrol back round the pump out of the lines and the filter, where some of that ends up once the engine has been run. That's why a DIY tank drain does not sort it — a myth. And, a can of petrol filled at the kerbside is genuinely dangerous.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's seldom carelessness. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the slip runs one way.
Habit and the vehicle falling out of step is when it happens. A new vehicle, a hire car or a courtesy car. Two motors on one drive, one petrol, one diesel. Your normal forecourt, its pumps suddenly 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 Passat in front of you on the forecourt for its first tank — that's when. Throw in a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up in Talgarth: avoiding petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the pump's label; the colour is just a hint.
- Plenty of motors state the fuel inside the filler flap or on the cap, and so check it on your first fill in a motor you do not know.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key if a home has one of each. So mark it.
- It seems silly and it works: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels come with a filler built to refuse a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Spotting it halfway? Stop there and then. A weaker blend results from less petrol in your tank, but your next step remains the same: do not fire it up.
Talgarth: already put petrol in a diesel?
Then, there is only a short order of things. Never fire it up, and don't turn the ignition on. Ask the staff to help you push it away from the petrol pump if you're still on the forecourt, whether that's Oil4Wales or anywhere else. What was put in, about how much, and if it's run: tell us that when you phone 0333 366 0103.
Say so if it was AdBlue instead of petrol: it is a separate issue, with its own page for Talgarth, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel task around Talgarth costs more than another
An honest single price doesn't exist here: four situations, four separate jobs. What moves the cost is chiefly which of them you're in. The ratio matters next, meaning how much of that tank is petrol, followed by the position of the vehicle and whether reaching it is safe for a van.
That's why we ask three questions before quoting instead of after: what was put in, how much, and if it's run. The answers turn a range into a straight figure.
About Talgarth and where it is
Talgarth is a small town in Powys, Wales, situated on the banks of the River Ennig at an elevation of around 125 metres. Talgarth lies near the towns of Bronllys and Tredustan, and is approximately 22 miles from Hereford. Talgarth has a population of around 1252 people, predominantly living in semi-detached housing. Talgarth is located in a rural area, with Trefecca nearby.
Across Powys and around Talgarth: fuel drain cover
Petrol in diesel call-outs around Talgarth — part of the LD postcode area — go to teams that likewise cover the places around it, Bronllys, Tredustan and Trefecca included. You need not move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
At the pump in Talgarth, right now?
Then you are in the best spot there can be. Keep it off. Phone.