Church Village: Petrol in a Diesel Car? How Worried to Be
Provided it has not been started, worry less than you probably are. Everyone in Church Village begins with "have I wrecked it?", and the honest answer is generally no: petrol resting inside your tank of a diesel stays harmless till priming, cranking or driving draws it into your fuel system. To leave it like that, ring Petrol in Diesel and leave the motor alone. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening a second time: that's the rest of this page.
Inside your engine: what petrol in a diesel really does
Two tasks fall to diesel on its journey round a motor. Before it ignites, it protects — and then it combusts. Designed to extremely fine gaps, the injectors and the pump depend on your diesel moving through them to keep their surfaces from wearing against one another.
Of these two jobs, petrol handles the first poorly and the second never. It is thinner than diesel and strips away the lubrication the system hinges 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's where the clattering comes from.
Put these together and the shape of the trouble is plain. The damage is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel fault. Once the pump has been labouring on that petrol, a mechanical issue has begun: whatever is shed by a pump that's grinding travels onward to the injectors with the fuel.
Four scenarios our engineers see in Church Village: how serious is petrol in a diesel?
Fuelled but not once started — as good as it gets. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With that petrol kept in that tank alone, it is emptied and cleaned on the spot, and nothing more is needed.
The ignition turned on, or a brief start. Petrol has left the tank and got to the filter and your lines, since your system has been bled. That's normally still an easy task — a drain, a flush, and the filter seen to.
A couple of miles driven, and the pump has spent every one of them labouring on thinned fuel. Miles is only half of it; how hard it was driven matters just as much. Either way the work includes that tank, the lines, the filter and fresh fuel through the entire circuit. The school run to the local primary school is one matter. Very different again: a trip to Cardiff, under 10 miles away, or some miles on the M4, under 5 miles from Church Village, where the engine kept labouring hard.
Driven until it protested. Knocking, an uneven idle, smoke, a throttle that has gone soft. The motor is telling you your fuel is no longer acting like diesel. Stop where you are — on the verge on St Illtyd Road, at the kerb, down a side road — and don't move it. What comes first is still the drain and flush, and that sorts it out, with permanent damage very uncommon if a car is pulled over soon.
Petrol in a diesel stories Church Village people hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — that tank just holds more of the same blend. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Finer components and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication count more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. Whilst the pump wears, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. A running engine does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct problem. None of what petrol diluted gets put back by it — and afterwards, your tank still contains that petrol.
The next start draws petrol back round the pump from your lines and the fuel filter, where some of it ends up once your engine has run. That is why draining the tank yourself doesn't leave you sorted — a myth. And, a can of petrol filled by the roadside is truly risky.
Petrol in a diesel: how does it take place?
It is rarely carelessness, and no one does it on purpose. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way.
It happens when routine and your car stop matching. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. A hurried fill on the way to Trefforest Estate with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it takes place. With rain, a call coming in, or children to deal with, the hand simply does what it always has.
Preventing petrol in a diesel next time you fill up in Church Village
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is only a clue.
- Plenty of motors state the fuel inside the filler flap or on the cap, and so check there on the first fill in any car you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, for a house with one of each.
- Before the nozzle comes off the pump the first time you fuel a hired or new motor, say "diesel" aloud. Silly, perhaps, yet it works.
- Tuck your phone away. This is an easy mistake to make whilst you are thinking about something else.
- Some diesels come with a filler designed to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- The moment you notice, stop: less petrol in your tank means a weaker mix. What to do next does not change, though — still do not fire it up.
Church Village: already put petrol in a diesel?
Then the order of things is short. Leave it unstarted, with the ignition off too. The staff on the forecourt — whether at Esso itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it's been run.
Say so if it was AdBlue instead of petrol: it's a separate issue, with its own page for Church Village, because AdBlue brings corrosion and deposits instead of lost lubrication.
Why one petrol in a diesel task around Church Village costs more than another
Four different jobs lie behind the four scenarios above — which is why there's no honest single quote. What shifts your cost is chiefly which of them you are in. Beyond that it's the share — how much petrol was put in against how much the tank holds — and after that where your car is and whether a van can get to it safely.
What went in, how much, and if it has run — three questions we ask before costing, not after, for exactly that reason. A range turns into a straight figure when the answers are in.
About Church Village, for a moment
Church Village is a riverside village in Rhondda Cynon Taf, situated near the banks of the River Taff and close to the nearby communities of Dyffryn Dowlats and Ton-Teg. Church Village has a mix of housing types, but detached homes are particularly prevalent, and the village is set at an elevation of around 101 metres. Church Village is located near the city of Cardiff, which is approximately 8.5 miles away, and is part of the wider commuter belt around the capital city of Wales.
Across Rhondda Cynon Taf and in Church Village: fuel drain cover
Church Village sits in the CF postcode area, and our teams that answer petrol in diesel jobs there work the locations near it as well — Dyffryn Dowlats, Ton-Teg and Upper Church Village among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers work, and your car does not need to move to us.
Still at the petrol pump around Church Village?
Then, you could not be in a better spot. Keep it off. Call.