Should You Worry? Petrol in a Diesel Car in Trelewis
Provided it has not been started, you can worry far less than you probably are. Until the ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank simply waits there and does nothing. Which makes the honest reply to the first Trelewis query — "have I ruined it?" — usually no. Petrol in Diesel is who to phone, with the engine kept off, and so it stays that way. Keep reading for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and ways to make sure you don't repeat it.
What petrol in a diesel does to the motor
Diesel does two jobs on its way through an engine. It protects first, and only then does it burn. Your high-pressure pump and your injectors are designed to extremely fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against one another.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump running on the blend wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the knocking.
Taken together, they show what shape the issue takes. The harm is done by circulation, not by contact. Where that petrol is only inside that tank, it is a fault of fuel, nothing more. After the pump has been working on that petrol, a mechanical issue has begun: anything shed by a pump that is wearing travels onward to your injectors with the fuel.
Trelewis, petrol in a diesel: four cases, from mild to serious
The best case there can be: filled up, not once started. At a forecourt, and genuinely only there, the petrol is still limited to the tank — because anywhere 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. With your system primed, the fuel lines and filter now hold petrol that came from your tank. That's usually still an easy job — a drain, a flush, and the filter seen to.
Driven a few miles. Now the pump has spent these miles working on thinned fuel. Tank, lines, filter, then fresh fuel put through the entire system: that is this work, and the way the vehicle was driven matters as much as the miles. Driving the children to the local primary school is one kind of trip. A run as far as Cardiff, under 15 miles away, is a very different task. So is any mileage on the M4, under 10 miles from Trelewis, where your engine has been labouring hard the whole time.
Driven till it complained. Rattling, a ragged idle, smoke, a throttle that has gone soft. What you are hearing is your motor signalling fuel that no longer acts like diesel. Pull up where you are — on the verge on St. Mary Street, at the kerb, down a side road — and do not move it again. The drain and flush still go first, and they deal with it: if a car is pulled over soon, long-term damage is very uncommon.
What Trelewis people get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It doesn't. Topping up takes out nothing; it gives you a bigger tank of the same mix. The assumption behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through smaller components: that's how a current diesel moves its fuel, so the protection counts more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops there. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Fine and running are not the same thing.
Myth: "Add some two-stroke oil and drive it home." It's an outdated fix for a different fault. That petrol is still in the tank afterwards, and whatever it has diluted isn't put back.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in your filter and lines, ready to go right back through your pump at your next start. And, a can of petrol filled by the kerbside is truly dangerous.
How petrol ends up: petrol in a diesel
No one does it on purpose, and it is seldom carelessness. 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, whilst a diesel nozzle mostly won't go into a petrol car at all. So the slip runs one way.
Routine and your car getting out of step is when it takes place. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. A train to catch, and a rushed fill on the way to Quakers Yard. 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 takes over.
Avoiding petrol in a diesel next time you fill up around Trelewis
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- Inspect the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on the first fill in a car you do not know.
- Label the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the pump the first time you fuel a hired or new motor, say "diesel" out loud. Silly, perhaps, but it works.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away and keep your mind on the pump.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- Stop as soon as you notice. Less petrol inside that tank makes a thinner mix. It does not change what to do next, which is still not to fire it up.
Already put petrol in a diesel in Trelewis?
Then, there's just a short order of things. Leave it unstarted, with the ignition switched off too. The attendants on the forecourt — whether at Gulf Treharris Service Station itself or wherever you filled up — will normally help push it clear of the pump if you ask. Ring 0333 366 0103 next, with three answers — the fuel, the rough quantity, and if it's run.
If it was AdBlue and not petrol, say so. That's a different fault — corrosion and deposits rather than lost protection — and it has its own page for Trelewis.
Why one petrol in a diesel job around Trelewis costs more than another
A fair single price doesn't exist here: four situations, four separate tasks. What shifts your cost is mostly which of them you are in. Beyond that it's the proportion — how much petrol was put in against how much the tank holds — and then where the car is and whether a technician can get to it safely.
Three queries come first, before any quote, rather than after — what went in, how much, has it run — and that is the reason. With those answers, there is a straight figure rather than a range.
About Trelewis, for a moment
Trelewis is a small village in Merthyr Tydfil, situated near the lakeside and surrounded by rolling hills. Trelewis has a population of around 1068 people and is characterized by its predominantly terraced housing. Trelewis is located near the Taff Merthyr Garden Village and other nearby communities such as Treharris and Melin Caiach. Trelewis sits at an elevation of 152 metres, approximately 14 miles north of Cardiff.
Across Merthyr Tydfil and around Trelewis: fuel drain cover
Trelewis rests in the CF postcode area, and the teams that answer petrol in diesel jobs there work the places near it as well — Treharris, Taff Merthyr Garden Village and Melin Caiach among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Still at the petrol pump in Trelewis?
In that case, you couldn't be in a better position. Switched off it stays; then ring.