How Worried Should You Be? Petrol in a Diesel Car in Johnstown
Unstarted? Then less anxious than you likely are. Until your ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank just waits there and does no harm. Which means the honest reply to the first Johnstown query — "have I wrecked it?" — usually no. To leave the car like that, ring Petrol in Diesel and leave your engine alone. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you don't do it again.
What petrol in a diesel does to the engine
Diesel has two tasks on its way through an engine. It protects first, and after that does it burn. Extremely fine clearances are built into your injectors and the high-pressure pump, and just your diesel flowing through stops those surfaces grinding together.
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 hear the rattling.
Seen together, they make clear what shape the problem has. Not contact but circulation is what causes the damage. All a tank with petrol in it amounts to is a fuel fault. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors further on.
Four situations our engineers see around Johnstown: how bad is petrol in a diesel?
Fuelled but not once started — as good as it gets. Only the tank has petrol in it, and so the job is emptying the tank and purging the system where your car stands. This scenario can only really occur at a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. Your system has been primed, so petrol has left the tank and reached the filter and your lines. Still generally straightforward: drain, flush, and the fuel filter seen to.
Driven a few miles. Now the pump has spent those miles labouring on thinned fuel. Miles is only half of it; how hard it was driven matters equally. Either way the work runs to that tank, the lines, the filter and fresh fuel through the whole system. Short trips, like the school run to the local primary school, are one thing. Getting as far as Wrexham, under 5 miles away, makes a very different task — as does any mileage on the M53, under 25 miles from Johnstown, with the motor running hard all the way.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. What you are hearing is your engine reporting fuel that no longer acts like diesel. Whether it's the verge on Bangor Road, a lay-by or a side street, stop there and leave it. What comes first is still the fuel drain and flush-through, and that sorts it out, with long-term damage very rare if a car is pulled over early.
What Johnstown drivers get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A fuller tank of the same mix is all it gives, since topping up removes nothing. Percentage isn't how a diesel fuel system copes with petrol, whatever that guidance supposes.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. Protection matters more on current diesels, not less, because their fuel passes through finer parts at higher pressure.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different problem. It does not put back what petrol has weakened, and the petrol is still in your tank later on.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in your filter and lines, ready to go straight back through your pump at your next start. Besides, petrol emptied into a can by the road is truly hazardous.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally will not fit a petrol vehicle, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in that direction.
Habit and the vehicle falling out of step is how it occurs. Hire cars, courtesy cars, and vehicles that are new to you. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Ruabon. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it happens. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel at your next fill-up in Johnstown
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what matters.
- The first fill in a strange motor is the time to check the filler flap — on it, or on the cap, plenty of vehicles state which fuel they take.
- One of each in the house? Mark your key to your diesel — a bright fob, a sticker — because intending to remember isn't enough.
- "Diesel", out loud, before you pick up the nozzle — every time a new or hired car gets its first tank. It sounds daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away and keep your mind on the pump.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- Less petrol means a thinner mix, and so stop the moment you notice — while remembering that your next stage is unchanged. It is still not to fire it up.
Already put petrol in a diesel around Johnstown?
In that case, there is just a short order of things. Don't turn your ignition on, and do not start it. The attendants at the forecourt — whether at BP itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Then ring 0333 366 0103 and tell us what went in, roughly how much, and whether it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate issue — Johnstown has a page all for it.
Why one petrol in a diesel task in Johnstown costs more than another
Four separate tasks sit behind the four situations above — which is why there is no honest single price. Chiefly, your cost moves with which one you are in. Beyond that it is the proportion — how much petrol got in against how much that tank holds — and after that where your car is and whether our van can reach it safely.
Three questions come first, before any quote, rather than after — what went in, how much, has it run — and this is the reason. The replies turn a range into a straight figure.
About Johnstown, briefly
Johnstown is a suburban area situated on the riverside in Wrexham county, with an elevation of 118 metres and a mix of semi-detached housing. Johnstown lies close to the nearby communities of Ponciau, Rhosllanerchrugog, and Pant, and is approximately 3.4 miles from Wrexham. Johnstown has a population of around 4114 residents and is located near the Welsh countryside. Johnstown's setting near the river contributes to its scenic surroundings.
Johnstown and Wrexham: where our fuel drain cover runs
The teams answering petrol in diesel calls around Johnstown, in the LL postcode area, also work the spots near it, Ponciau, Rhosllanerchrugog and Pant included. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our technicians work, and the vehicle does not need to move to us.
At the pump around Johnstown, still?
The best spot there is, then — that is where you are. Keep it off. Ring.