Petrol in a Diesel Car in Lower Feltham: How Worried Should You Be?
Provided it has not been started, you can worry less than you likely are. Petrol sitting in a diesel tank does nothing to your engine till something draws it through the system — the ignition priming your pump, the starter, or the drive itself. So the truthful answer to the first question anyone around Lower Feltham asks, "have I ruined it?", is normally no. Leave the motor off and ring Petrol in Diesel — that is how you keep it like that. Further down, 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.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey round a motor. It ignites, and before it burns it lubricates. The high-pressure fuel pump and your injectors are made to extremely fine clearances, and the diesel passing through them is what stops those surfaces from wearing against each other.
The second task petrol does not do at all, and the first it does poorly. The knocking comes from petrol being designed not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection the system depends on, and any pump working on that mix is wearing itself.
Taken together, they make clear the shape the trouble has. The harm is done by circulation, not by contact. Petrol in a tank is a fuel problem. The beginning of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors beyond it.
Petrol in a diesel in Lower Feltham: how serious is it? Four situations
Filled but never started — as good as it gets. The petrol is in that tank and only your tank, and the job is a drain and a flush where your car stands. This is the one scenario that can only really take place on a forecourt, because anywhere else your car has been driven to get there.
Started for a second, or only your ignition on. Petrol has come out of your tank and got to the filter and the lines, because your system has been primed. That is usually still a straightforward job — a drain, a flush, and your filter dealt with.
The pump has worked a couple of miles on thinned fuel — that's what driving it does. Mileage is only half of that; how hard it was driven counts equally. Either way this work runs to the tank, your lines, the filter and fresh fuel through the entire system. On the school run to Oak Hill Academy West London, the mileage is short. Any distance on the M3, under 3 miles from Lower Feltham, means the engine has worked hard throughout, and a run to Westminster, under 15 miles away, makes a very different job too.
Driven on until it protested — knocking, smoke, a lumpy idle, a dead throttle. That is the engine telling you its fuel has stopped acting like diesel. Stop where you are — on the verge on Briarwood Close, at the kerb, down a side road — and do not move it again. The drain and flush still come first, and they deal with it: if a car is stopped soon, permanent damage is very rare.
Lower Feltham motorists and the petrol in a diesel myths they hear
"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 — the tank just carries more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance supposes.
"Modern diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through more precise components: that is how a newer diesel moves its fuel, so the protection counts more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up most drivers than any other. Diesel in a petrol motor normally means a motor that won't run: the motorist stops, and so does the damage. Feed petrol to a diesel and it generally starts, ticks over and drives away like nothing has happened — all the while its pump wears. Running is not the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, meant for another problem. The petrol is still in your tank after that, and what it has weakened isn't put back.
Once the engine has run, part of the petrol sits in the filter and your lines, not your tank — and the next start pulls it right back through the pump. So the myth "drain the tank yourself and you are sorted" doesn't stand up. And, a can of petrol drained by the kerbside is genuinely risky.
How it happens: petrol in a diesel
A careless moment is rarely the cause, and nobody means to do it. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol motor at all. So the error runs one way.
The moment routine stops matching the vehicle is the moment it occurs. A car that's new to you — a hire car, on loan as a courtesy car, or just bought. Two motors on one driveway, one petrol, one diesel. A forecourt you know, only with its pumps arranged differently. A train to catch, and a hurried fill en route to Feltham. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Add a back seat full of kids, a phone call or rain, and habit wins.
Next time you fill up in Lower Feltham: avoiding petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is just a clue.
- Plenty of motors state the fuel type inside the filler flap or on the cap, and so check there on your first fill in a motor you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, for a household with one of each.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems silly. It does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices are available for cars without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- The moment you realise, stop: less petrol in that tank makes a thinner mix. What to do next doesn't change, though — still do not fire it up.
Already put petrol in a diesel around Lower Feltham?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition off as well. Ask the staff to help you push it clear of the petrol pump if you are still on the forecourt, whether that is Tesco or somewhere else. Then ring 0333 366 0103 and tell us what was put in, roughly how much, and if it's run.
Say so if it was AdBlue instead of petrol: it's a separate fault, with its own page for Lower Feltham, since AdBlue brings corrosion and deposits rather than lost protection.
Why one petrol in a diesel job around Lower Feltham costs more than another
Four different tasks lie behind the four scenarios above — which is why there is no fair single price. The scenario itself does most of the work of moving the cost. The ratio counts next, meaning how much of the tank is petrol, followed by the location of the car and whether getting to it is safe for our van.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and that is the reason. The answers turn a range into a straight figure.
About Lower Feltham and its setting
Lower Feltham is a suburban area in west London, situated approximately 13.8 miles from central London. Lower Feltham has a relatively low elevation of around 13 metres, and is characterised by its semi-detached housing stock. Lower Feltham is located near several other suburban areas, including Felthamhill, Ashford Common, and East Bedfont.
Lower Feltham and Greater London: where our fuel drain cover reaches
Petrol in diesel calls around Lower Feltham — part of the TW postcode area — go to vans that also cover the locations around it, Felthamhill, Ashford Common and East Bedfont included. Our technicians drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the pump around Lower Feltham, right now?
The best position there is, then — that's where you are. Keep it off. Ring.