Put Petrol in a Diesel Car in Tolmers? Don't Start It
Petrol in Diesel drains and cleans wrongly fuelled cars where they stand, on the forecourt, by the roadside or on a drive, throughout Tolmers and the remainder of Hertfordshire. The very first thing to do is not to start the engine. While the motor has not run and the petrol is still inside that tank, a tank drain is nearly always all it needs, and the next few minutes decide that, not how much got in. Phone and then our team will show you what happens next before you attempt anything else.
Petrol in a diesel: what to do first
- Feed a petrol motor diesel and it will typically refuse to run at all, and so the driver stops there and so does the wear. Give a diesel petrol and the thing starts, it ticks over, it drives off — fine for a couple of miles. Motorists have that muddled, which is the bit they get wrong about petrol in a diesel in particular. So never fire it up. And if started, do not believe it: the fuel system is wearing down as you drive.
- Two things, diesel: it combusts, and on the way through it keeps that high-pressure fuel pump and injectors greased. Petrol only does the one. That is why the car's ignition stays off as well — turn it on and you frequently prime the system, and that is petrol leaving the tank for exactly those components.
- Topping up clears nothing. It gives you a bigger tank of the same blend, since a diesel fuel system does not handle petrol by percentage as that advice assumes — so never put diesel on top to weaken it. Grade is irrelevant too: super unleaded is petrol.
- Stay still if it's wise to. Hazards on, motor off, keep the car. Wherever you have stopped — the verge on Hill Leys, anywhere — a tricky place for us is better than a started motor, and nothing is simpler for us to sort than a motor that never moved.
- Have your whereabouts ready before you phone. A postcode starting EN6 4 and whatever is next to you with a name on it is the difference between a van turning up and our van circling.
- Three details determine the entire visit: the fuel you tipped in, the ballpark volume of it, plus if anything has been going since. The number is 0333 366 0103.
At the forecourt: draining petrol from a diesel
A fair part of the job gets done at a forecourt, as that's where it usually kicks off. Still at Elliott Motor Company? Then that is generally where it happens. Petrol station forecourts are normal for us, with the agreement of the station.
At the forecourt, it is stopped with the motor never started, and nowhere else manages that. The few seconds between checking the receipt and going for the key decide how much needs flushing. Everywhere other than the forecourt — a car park, a driveway, a lay-by — the car was started and driven to get there, so fuel was sucked from that tank, through the filter then into the high-pressure fuel pump. That means the fuel lines and your filter require rinsing as well as your tank. It's not a catastrophe, and we can still deal with it where the car is.
The attendants will normally happily push the car out from the petrol pump so the next motorist can get by. That's worth doing. Shifting the car four lengths doesn't merit firing it.
How much fuel the pump has drawn is what we're really asking — not how long ago any of it was. So the call our technicians hope for runs like this: diesel Renault Clio, some litres of unleaded, a couple of miles covered, now shut off outside The Co-operative Food.
What our technicians will want to know is whether that trip there was brief and cold, because that's where petrol is slowest to burn fully — and whatever doesn't burn can work past the piston rings and into the sump. Right up to the moment somebody drives it home, a diesel Ford Focus parked in the car park by The Plough with a tank full of petrol in it is a straightforward job. Nothing worsens whilst it waits, so leave the car there overnight and phone us in the morning.
Here is the whole mechanism. Diesel needs enough body to seal the tight tolerances it goes through, and petrol takes that away. That is it. Which accounts for the normal Home Wood call — a diesel Mercedes C-Class, out there without a murmur and back down on power, lumpy at idle, perhaps a bit of smoke. Injection systems work hydraulically as well as chemically, so your fuel has to hold pressure and not just burn; weakened, it bleeds past those tolerances rather than building, and delivery comes poorer, later, less even than the engine was designed about. Not a failing motor, though. Fuel that has stopped behaving like diesel. Put that right and it stops.
Hire car? Company car? Ring them before us. Some agreements want the firm to sign off the work, and that is much quicker dealt with up front than after that. Then ring us about the Peugeot 3008, the diesel one, by Cuffley Hall. Don't worry that you cannot say how full that tank was — nearly no one can two days into a motor, and it's something our technicians establish on the spot. The reason for asking: damage from petrol in a diesel is a matter of proportion. A few litres in a nearly empty tank make a far stronger mixture than in a full one, and petrol is built to resist the very thing a diesel needs of that, which is igniting when compressed. Stronger mixture, more knocking, more smoke, flatter throttle.
Somebody certain will tell you to drain it and put fresh diesel in. Half true, that. Try it on a diesel Citroen C3 close to Cuffley Library and your engine will start — which is exactly why it sounds like sense. Here is the trouble: there's petrol left in the filter and the feed lines, and the first thing your engine does is pull it back through your pump a second time. Draining a tank achieves nothing about fuel that already left the tank. Ring us. Your system gets purged, your filter comes off where there is one worth removing, and that's what separates a fixed vehicle from one that simply starts.
Can our technicians cover your part of Tolmers?
Cuffley, Newgate Street, Goffs Oak, Lucas End, Tylers Causeway — all of those on our trips that take us over to Tolmers too, a small village.
There are pages for nearly all places in Hertfordshire, and the ones mentioned above are merely the closest neighbours — so yours being absent from the list tells you nothing about if our technicians come. Guessing is the mistake to skip, especially on the border or anywhere the satnav fails. Call us to enquire.
This map is the ground this page spans. Roadside, forecourt, drive, car park: every bit of it is ground our engineers serve, and none of it asks your car to come to us.
Kerbside stops across Tolmers
The chance to pull in anywhere suitable doesn't come to everybody. If you noticed after setting off and landed along the verge on Thrush Lane, or at a lay-by somewhere with the hazard lights on, that's a common call for us and not an odd one.
Whether you sit beside the car or step away from it hangs on whether staying nearby looks safe. Don't fire it up to get to a safer place. It will go — a diesel on petrol generally obliges — and each mile of obliging draws the blend deeper into the system. However awkward the location, it's no bother for us to get to it, and that is far better for the car than carrying on.
Run it already? Pull over, and check below
under 3 miles out of Tolmers, your M25 is what counts now. A loss of power, an uneven idle, some smoke: those are the signs when they arrive, rather than a clean stop — and a misfuelled diesel will frequently get you onto it and some distance along before anything seems wrong at all.
Take the first junction that's safe, stop there, and don't restart the vehicle to reposition. It affects what our engineers bring, so mention it when you call: on a longer drive — anything approaching the under 15 miles to the nearest city — take it the mixture has been through your filter, your pump and your injectors.
A little about Tolmers
Tolmers is a locality in Hertfordshire, situated on the riverside at an elevation of 68 metres, with detached housing being the predominant type of accommodation. Tolmers lies approximately 14.4 miles from London and 10 miles from St Albans, placing it within commuting distance of both cities. Tolmers is surrounded by other nearby places, including Cuffley, Newgate Street, and Goffs Oak, and has a population of around 1380 residents. Tolmers occupies a scenic position in the Eastern region, with the River Lea flowing nearby.
What happens when our engineers get to you in Tolmers
- We ask first, price after. What was put in? How much? Has the motor run? Those replies alter what the work really is.
- The polluted mixture comes from the tank.
- Lines purged, filter cleared. Whatever remains later is not the thing that caused the trouble.
- Priming follows, once new diesel is in.
- It is started with new diesel in it, and our engineers make sure that it's running smoothly.
From there, you're ready to set off. There is no need to go to a garage at any stage, since the work is all done where your car is, and when it's spotted soon, long-term damage is very unusual.
Tolmers AdBlue removal is a distinct problem
Don't crank it: that first rule holds whether what went in was AdBlue or petrol. What differs is this issue itself. Petrol weakens the diesel and strips the lubrication the system depends on. AdBlue is urea dissolved in water, and in a diesel tank it causes rust and residue in its place.
Both are ours. There's a separate Tolmers page for AdBlue removal, with the detail on it — including the reasons it often turns out to be the worse of the two.
What a petrol-in-diesel fuel drain costs in Tolmers
Our engineers can't put one price on this page frankly, since this job is not one job. What moves it:
- This is the big one: whether your motor has been run, or driven.
- How much of the wrong fuel was put in, set against how much the tank holds.
- Which got in: unleaded or AdBlue.
- Whether a van can safely get to the car and work on it, which hinges on where your car is.
The car, the quantity, whether it has run — give us those and the answer comes back firm rather than as a range. Not urgent, with the car at home and going nowhere? Then is fine.
Petrol in diesel: common questions in Tolmers
Fuel drains on a Tolmers petrol station forecourt
A large share of this work takes place there, so yes. Tell us which one you are at when you ring and we'll tell you if we can work there. With the owner's agreement our technicians work at Shell and the other forecourts around town routinely.
Is there a sensible amount of petrol in a diesel?
Litres aren't the measure. Proportion is, and a lot more than either, it matters whether anything has been run. Five litres into a nearly dry tank isn't five into a full one, no. But both land on the same query in the end: has that mixture been pulled right through, or has it not?
I put petrol in my diesel and drove the vehicle. What next?
Pull over somewhere safe, turn off, and keep the car off. It's recoverable a lot more often than drivers assume, even though driving is what shifts the trouble from the tank into the pump and injectors — and the single most helpful thing you can do now is not restart it.
Fuel drains and manufacturer warranties
It is not a modification, and so a drain and flush carried out correctly doesn't invalidate a manufacturer's warranty. A disagreement over a warranty is likelier to come from running a diesel on petrol — so leave it switched off.
Could I put some two-stroke in and just drive?
No. Two-stroke oil is an old remedy for a separate issue and it does not restore what petrol has thinned. The pump still has to live with it, as the tank still has petrol in it afterwards.
Do I need a main dealer for petrol in a diesel?
No. We drain and flush the car wherever it is, so there's no need to bring it to a franchised dealer.
Is the vehicle still with you?
Keep it turned off.
If you have already driven the car, pull in somewhere safe, switch it off and keep it off. This is recoverable from much more commonly than people assume, and a stationary, cold motor is the best position to be in.
Throughout Hertfordshire and around Tolmers: call-out fuel draining, at home or on the forecourt or at the roadside.