Hook Street: Put Petrol in a Diesel Car?
Never turn on your engine. While the fuel is still in your tank and the engine has not turned over, a tank drain is nearly always all it takes — and that's decided in the next few minutes, not by how much got in. Petrol in Diesel drains and flushes wrongly fuelled cars where they stand, all over Hook Street and the rest of Wiltshire, on the forecourt, at the roadside or on a driveway. Ring us before all else starts, so you'll know what comes after that.
Your first five steps: petrol in a diesel
- Never start it — and never trust it if it fires up. Here is the thing motorists get wrong about petrol in a diesel in particular. A petrol motor fed diesel typically just will not run, so the motorist stops and the damage ends with them. A diesel fed petrol usually starts, ticks over and drives off quite happily for several miles. It isn't okay. It is grinding your fuel system while you drive.
- Two jobs, diesel: it combusts, and on the way through it keeps the injection pump and injectors oiled. Petrol only handles the one. That is why the ignition is left off too — switch it on and you often prime your system, and that's petrol leaving the tank for exactly those components.
- Topping up clears nothing. It hands you a bigger tank of the same mix, because a diesel fuel system does not tolerate petrol by percentage in the way that guidance implies — so don't tip diesel on top to thin it. Octane is beside the point too: super unleaded is petrol.
- Our team would sooner travel to an odd location than have it started — so if you safely can, stay still. Nothing is quicker to handle than a motor that has never shifted. On the verge on Hook Street, that means hazards on then keep it.
- Before you ring, gather your position. Anything closest to you with a name on it, plus a postcode starting SN4 8 — that is what decides whether the technician arrives or circles.
- Phone 0333 366 0103. Tell us what was put in, approximately how many litres, and also whether the car has started. Those three replies determine the entire visit.
Can petrol be pumped from a diesel on the forecourt?
Much of this work starts at a pump, meaning a fair part of that is done at one. Our technicians work on station forecourts routinely, with the site's consent, and so if you're still at Esso that is usually where the drain gets done.
No place other than a forecourt can it be caught with the motor still unrun. Our engineers can still sort it out where it is, even away from the forecourt. In a car park, on a driveway or in a lay-by, the vehicle has been switched on and driven there, and that drew fuel through the fuel filter and into your high-pressure pump, all the way from the tank. None of that is a calamity, though the flush then has to reach past that tank to your lines and your filter, and the few seconds between checking the till receipt and reaching for the keys are what decide that.
Away from the petrol pump, the next customer can get by — so yes, let the staff help you move the vehicle. Very much worth doing. Firing it for four car lengths? Not a chance.
Areas we reach in Hook Street
Being a village, Hook Street has a frequent call, and the villages round about come along on the same round: Hook and Lydiard Green, Greatfield and Lydiard Millicent, Coped Hall.
If yours is not on that list it does not mean we do not come — there are dedicated pages for the majority of places across Wiltshire, and the ones mentioned above are simply the immediate neighbours. Close to the boundary, or somewhere your phone struggles with? Contact us to enquire rather than assuming.
The map is the patch the page covers. The car never needs to come to us. Our technicians work across the lot — kerbside, forecourts, driveways, car parks.
Nothing tells you, because from behind the wheel there is nothing to be warned about. The diesel Peugeot 308 will have seemed perfectly ordinary on the way back from Lydiard Millicent CofE Primary School, and they all do — which is the snag with petrol in a diesel and not the reverse. Diesel in a petrol car usually refuses to run, stopping the driver and stopping the harm with them. Petrol in a diesel starts, ticks over, pulls away as though nothing had happened, and all the while your pump does its work without the protection its fuel is meant to supply. Tell us about how far, and how hard. The harder matters more.
Do not chance it. The journey home from The Bolingbroke Arms is entirely possible, which is precisely the problem — a diluted tank does not stop a diesel starting or pulling away, it just wears the parts the fuel is meant to protect. Call us, then let the Ford Focus stay where it sits.
Here's the whole process. Diesel needs enough body to seal the fine tolerances it goes through, and petrol takes that away. That is it. Which accounts for the usual Park Copse call — a diesel Mercedes C-Class, out there without complaint and back down on power, lumpy at idle, perhaps a bit of smoke. Injection systems work hydraulically as well as chemically, so the fuel has to hold pressure and not just burn; weakened, it escapes past those tolerances and not building, and delivery comes poorer, later, less even than your engine was designed about. Not a failing engine, though. Fuel that has stopped behaving like diesel. Put that right and it stops.
Hire car or company car? Ring them before you phone us — some contracts want the hire firm to approve the work, and sorting that out first is a great deal faster than sorting it later on. Then ring us about the BMW 1 Series by Lydiard Millicent Parish Hall, and don't worry that you can't say how full the tank was. Nearly nobody can, in a car they picked up two days ago, and our technicians work it out on site. The reason we ask is that petrol in a diesel does its damage as a ratio: the same few litres in a nearly empty tank is a far stronger mix than in a full one. Petrol is rated on how well it withstands igniting under pressure, which is the opposite of what a diesel needs — so the stronger the mix, the more it rattles, smokes and goes flat.
Drain it and put new diesel in — that's the suggestion you will get, usually from somebody certain, and it is only half right. Do precisely that to a diesel Citroen C3 close to Jungle Parc and it would start, which is what makes the advice sound plausible. What takes place next is the issue: your engine at once draws the petrol still resting in the filter and the feed lines straight back through the pump, as draining a tank does nothing about fuel that has already left it. Call us instead. Our technicians flush your system and take the fuel filter off where the car has a working one, which is the difference between the car being repaired and your car merely starting.
Stranded by the roadside somewhere around Hook Street?
Not everybody gets the chance to pull in somewhere sensible. Set off, then noticed? Finished up by the verge beside M4, or sat in some lay-by with the hazards flashing? That is a routine call here. Not an odd one.
Clear of the car while it isn't wise to sit in it, by it if it is. It will frequently oblige. A diesel running on petrol limps along perfectly willingly, and that is the catch: restart it to get to somewhere handier and the mixture goes further into the system with every mile covered. We will bring the van to an inconvenient place without any trouble, and for your car that is a lot better than driving on.
Driven it already? Pull over, then check this
This is where the local M4 comes in, under a mile away from Hook Street. A misfuelled diesel will frequently take you onto it and some distance along before anything seems wrong, while the signs when they come are usually a loss of power, an uneven idle and some smoke rather than a clean stop.
Pull off at the next sensible exit, turn off, and never start the car to reposition. It alters what we bring, and so mention it when you call: on a longer trip — anything near the under 25 miles to the nearest city — take it the mixture has been through the filter, the pump and the injectors.
A bit about Hook Street
Hook Street is a small village in Wiltshire, situated on the riverside at an elevation of 129 metres, with detached housing being the predominant type of accommodation. Hook Street lies near the villages of Hook and Lydiard Green, and is within commuting distance of the city of Bath, which is 24 miles away. Hook Street remains a quiet residential community with a population of around 531 people. Hook Street is also close to other nearby places such as Greatfield, and is about 75 miles west of London.
What happens when our engineers reach you around Hook Street
- The replies change the work, which is why we ask before giving a price: what got in, how much of that, and if your engine has run.
- The tank is emptied of everything.
- Our engineers flush the fuel lines and clear the filter, and so what's left in the system is not what caused the problem.
- New diesel goes in, and then your system gets bled.
- It's started with new diesel in it, and our engineers check that it's running correctly.
That has it ready to pull away. There is no need to go to a garage at any point, as the work is all done where the car is, and when it's noticed soon, lasting damage is very uncommon.
Hook Street AdBlue removal is a different problem
If what got in was AdBlue instead of petrol, the opening step is the same — do not fire it up — but the fault is not. Petrol weakens your diesel and strips the protection the fuel system relies on. AdBlue is urea in water, and in a diesel tank it causes corrosion and residue instead.
Both are ours. There's a separate Hook Street page for AdBlue removal, with the full story on it — including the reasons it frequently turns out to be the worse of the two.
Hook Street prices for a petrol-in-diesel drain
Truthfully, no single price fits on a page like this. This job changes. Here is what varies it:
- Started? Driven? Either answer counts more than anything else on this list.
- The tank's capacity, set against how much of the wrong fuel went into it.
- AdBlue or unleaded, whichever went in.
- Where your car is, and whether a van can sensibly get to and work on it.
The vehicle, the quantity, whether it has run — give us those and the answer comes back clear and not as a range. Motor at home, going nowhere, nothing urgent about it — is fine for that.
Hook Street motorists ask us these about petrol in diesel
Can you do a fuel drain at a petrol station in Hook Street?
Yes — forecourts are where a big share of this takes place. Tell us which one you are at when you ring and we'll tell you whether our engineers can work there. With the owner's consent we work at BP and the other forecourts around town regularly.
How much petrol is too much for a diesel?
Ratio settles it instead of litres — and more than either, whether the motor has run. What settles how much work is required is if that mix has been pulled through the fuel system — because even though five litres in an almost empty tank is a distinct situation from five in a full one, either way that is the question.
I drove the vehicle after putting petrol in my diesel. What now?
Somewhere sensible, then stop, then switch off and keep it off. Driving is what moves the problem from that tank into the pump and injectors — but it's recoverable much more commonly than motorists fear, and the single most helpful thing you can do now is not restart the vehicle.
Fuel drains and manufacturer warranties
No. Carried out properly, clearing and rinsing is no alteration at all, and the warranty from your manufacturer is untouched by it. Running a diesel on petrol is the thing likelier to cause an argument with one, which is another reason to leave it switched off.
Can I just add two-stroke oil and drive home?
What petrol has weakened isn't put back by two-stroke oil, which is an old fix for a different problem. So no. Later on? Still petrol in that tank, and a pump that has to put up with the stuff.
Do I need a main dealer for petrol in a diesel?
Wherever the car is, our engineers drain and flush it there, so a drive to the main dealer does not come into it.
Waiting next to it?
Switched off is how the car stays.
Switch it off somewhere safe and leave it off, if you have already driven it. Cold, stationary, going nowhere: that's the best place to be in. Motorists fear this much more than they need to.
Emptying misfuelled cars, Hook Street and the rest of Wiltshire, wherever they are. Kerbside. Forecourt. Home.