Should You Worry? Petrol in a Diesel Car in Coleraine
Far less than you likely are, provided it hasn't been started. Till the ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank simply rests there and does nothing. Which makes the truthful reply to that first Coleraine question — "have I ruined it?" — usually no. Petrol in Diesel is who to call, with the engine kept off, so it stays that way. Below, this page sets out what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you again.
The engine and petrol in a diesel: what goes on
Passing through an engine, diesel does two things at the same time. It ignites, and before it combusts it lubricates. Designed to extremely fine clearances, the injectors and the pump depend on your diesel flowing through them to stop their surfaces wearing against one another.
Petrol handles the first job poorly and the second not at all. The rattling comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication your system depends on, and any pump working on that mix is wearing itself.
The shape of the problem is plain once you put those together. It is circulation that does the harm, not contact. Where that petrol is only in your tank, it is a fault of fuel, nothing more. 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 fuel injectors beyond it.
Four scenarios our technicians see around Coleraine: how bad is petrol in a diesel?
Filled but never started — as good as it gets. At a forecourt, and truly only there, that petrol is still confined to your tank — because anywhere else your car was driven to reach it. The job is emptying and purging on the spot.
Ignition on, or started for a moment. With your system primed, the lines and filter now hold petrol that has come from your tank. That is generally still an easy job — a drain, a flush, and the filter seen to.
Those few miles driven were the pump running on fuel diluted by petrol throughout. Miles is only half of it; how hard it was driven counts just as much. Either way this work runs to that tank, the lines, the filter and clean fuel through the whole system. The school run to the local primary school is one matter. Very different once more: a trip to Derry, under 50 miles away, or any mileage on the M77, over 50 miles from Coleraine, where the motor never stopped labouring hard.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The fuel isn't behaving like diesel any more, and the engine is saying so. Whether it's the verge on Rock Street, a lay-by or a side road, stop there then leave it. Permanent damage is very uncommon when a vehicle is stopped early, and the drain and flush-through that still come first sort it out.
Petrol in a diesel myths Coleraine drivers hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed by topping up — you're left with a bigger tank, still the same mix. A diesel fuel system does not accept petrol by percentage in the way that advice supposes.
Myth: a newer diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through more precise parts: that is how a newer diesel moves its fuel, and so the lubrication matters for more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there's no damage done." Any petrol engine fed diesel generally will not run, and so the driver stops and the harm stops with them. Feed petrol to a diesel and it normally starts, idles and pulls away as if nothing has happened — all the while its pump is wearing. Fine and running are not the same thing.
An outdated fix for a distinct fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It does not put back what petrol has thinned, and the petrol is still in your tank after that.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in your filter and lines, ready to go right back through your pump at your next start. Draining petrol into a can at the kerbside is also genuinely dangerous.
How petrol ends up: petrol in a diesel
It's rarely carelessness, and nobody does it on purpose. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol motor at all. So the mistake runs one way.
Habit and the vehicle falling out of step is how it happens. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A rushed fill en route to the nearest station 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. Throw in a back seat full of kids, a phone call or rain, and habit wins.
How to avoid petrol in a diesel on your next fill-up around Coleraine
- Check the pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on every forecourt. The label is what counts.
- The first fill in an unfamiliar vehicle is the time to check the filler flap — inside it, or on the cap, many cars state which fuel they take.
- Label your key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It sounds silly and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- While you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop reading the pump.
- As soon as you notice, stop: less petrol in your tank makes a thinner mix. What to do next doesn't change, though — still don't start the car.
Coleraine: already put petrol in a diesel?
Then the order of things is short. Don't switch your ignition on, and don't fire it up. Ask the attendants to help you roll it away from the pump if you're still at the forecourt, whether that's the nearest petrol station or anywhere else. Then ring 0333 366 0103 and tell us what got in, roughly how much, and whether it has run.
Corrosion and deposits are the trouble with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Coleraine page.
What makes one Coleraine petrol in a diesel job cost more than the next
There's no honest single quote for this, because the four scenarios above are four separate tasks. The situation itself does most of the work of moving your cost. After that it's the share — how much petrol was put in against how much your tank takes — and then where the vehicle is and whether a technician can reach it safely.
Ahead of any quote, not after, we ask three questions: the fuel that got in, its volume, and if it has run. That's why. Given the answers, you get a straight figure rather than a range.
About Coleraine
Coleraine is a town in County Londonderry, situated inland near the River Bann. Coleraine sits at a relatively low elevation of 12 metres, approximately 27 miles from Derry. Coleraine is surrounded by nearby places such as Ballyrashane, Macosquin, and Portstewart, and its population is around 10,214 people, predominantly living in terraced housing.
Across County Londonderry and in Coleraine: fuel drain cover
Ballyrashane, Macosquin and Portstewart are among the locations around Coleraine that the same vans work, answering petrol in diesel jobs across Coleraine's BT postcode area. No need to move your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations we drain.
Coleraine: still at the pump?
In that case, you could not be in a better place. Keep it off. Call.