Petrol in a Diesel Car in St Columb Major: How Worried Should You Be?
Far less than you probably are, if it hasn't been started. Everyone in St Columb Major starts with "have I wrecked it?", and the fair answer is usually no: petrol resting in your tank of a diesel remains harmless until priming, cranking or driving pulls it into the fuel system. To leave it that way, call Petrol in Diesel then leave the motor switched off. Read on 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.
Petrol in a diesel: what does it do to the motor?
Passing through a motor, diesel is doing two things at once. It burns, and before it burns it lubricates. Made to extremely fine tolerances, the fuel injectors and the pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
The second task petrol does not do at all, and the first it does poorly. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump running on the mixture wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the clattering.
Put those together and the shape of the problem is clear. Not contact but circulation is what causes the damage. Where that petrol is only inside the tank, it is a fault of fuel, nothing more. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Four situations our engineers see in St Columb Major: how bad is petrol in a diesel?
Fuelled but not once started — as good as it gets. The petrol is in your tank and just your tank, and the job is a drain and a flush where the car sits. This is the one situation that can only really happen at a forecourt, as anywhere else your car has been driven to get there.
A brief spell of running, or merely the ignition on. With the system primed, the lines and filter now contain petrol that came from the tank. Normally little more than clearing, purging and sorting the fuel filter, and so still straightforward.
Driven a couple of miles. Now the pump has spent these miles running on weakened fuel. How hard the vehicle was driven counts as much as how far, and the work covers that tank, your lines, the filter and clean fuel through the entire circuit. Short trips, like the school run to St Columb Major Academy, are one matter. A run as far as Truro, under 15 miles away, is a very different job. So is any distance on the M5, over 50 miles from St Columb Major, where the motor has been labouring hard throughout.
Driven on until it complained — clattering, smoke, a lumpy idle, a soft throttle. The fuel is not behaving like diesel any more, and your engine is saying so. Stop wherever you are — the verge on Broad Street, a lay-by, a side street — and leave it where it is. What comes first is still the fuel drain and flush, and that takes care of it, with permanent damage very unusual if a vehicle is pulled over quickly.
What St Columb Major people get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." A fuller tank of the same mixture is all you get, since topping up takes out nothing. The idea behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." More precise components and higher pressure are how a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
The myth that catches people out: if it starts and drives, it must be unharmed. The motorist of a petrol motor fed diesel normally stops, because it will not run, and the harm stops there. Whilst your pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Fine and running are not the same thing.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, meant for another problem. What petrol has weakened stays diluted, and that petrol remains inside your tank anyway.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol sits in the fuel filter and lines, waiting to go straight back through the pump on your next start. Clearing petrol into a can by the kerbside is also genuinely risky.
How does petrol in a diesel happen?
Nobody does it on purpose, and it is rarely carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it easy, and the error runs one way.
Habit and the vehicle getting out of step is how it occurs. Hire cars, courtesy cars, and cars that are new to you. One petrol and one diesel on the driveway of the same household. A forecourt you know, but with its pumps arranged differently. Fuelling up in a hurry on the way to St Columb Road, with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. The hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up in St Columb Major
- The label is what matters, so read the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- Many motors state the fuel type inside the filler flap or on the cap, and so check there on the first fill in any vehicle you do not know.
- Label your key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Before the nozzle leaves the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, yes, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away and keep your mind on the pump.
- Some diesels have a filler built to block a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Less petrol makes a weaker mix, and so stop as soon as you notice — though remembering that your next step is unchanged. It's still not to crank it.
St Columb Major: already put petrol in a diesel?
The order of things is brief, then. Starting it is out, and so is turning on the ignition. If you're still at the forecourt — Gulf or anywhere else — ask the staff to help you push the vehicle away from the pump. What got in, roughly how much, and whether it's run: tell us that when you phone 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different problem — St Columb Major has a page just for it.
One petrol in a diesel job in St Columb Major costs more than another. Why?
Four separate jobs lie behind the four situations above — which is why there's no fair single quote. Chiefly, your cost shifts with which situation you are in. The proportion counts next, meaning how much of your tank is petrol, followed by the position of the vehicle and whether getting to it is safe for a van.
That is why we ask three questions before pricing rather than after: what got in, how much, and if it has run. With the answers, there is a straight figure instead of a range.
About St Columb Major and its setting
St Columb Major is a town in Cornwall, situated inland at an elevation of 94 metres, approximately 12.8 miles from the city of Truro. St Columb Major has a population of around 3663 people, with a predominance of semi-detached housing. St Columb Major is surrounded by smaller settlements, including Gluvian, Lanhainsworth, and Tregatillian, and is located about 222.1 miles west of London.
Fuel drain cover in St Columb Major and across Cornwall
Petrol in diesel call-outs around St Columb Major — part of the TR postcode area — go to teams that likewise cover the spots round it, Gluvian, Lanhainsworth and Tregatillian included. The vehicle does not need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
St Columb Major: still at the pump?
The best position there is, then — that is where you are. Phone, and keep it switched off.