Thundridge: Put Petrol in a Diesel Car?
With that tank still holding the petrol and your engine not yet started, nearly every job takes only a drain, so leave the engine off. That result is settled in the minutes immediately after filling up, and not by the amount that got in. Across Thundridge and the rest of Hertfordshire, Petrol in Diesel drains the car and cleans it where it sits, whether by a roadside, on a driveway or at a forecourt. Just one call to us is enough: we will show you what follows after this. Do this straight away.
Petrol in a diesel: what to try next
- Give a petrol motor diesel and it will typically refuse to run at all, so the driver stops there and so does the harm. Feed a diesel petrol and the engine starts, it ticks over, it moves off — all right for a couple of miles. Motorists have that reversed, which is the part they get wrong about petrol in a diesel specifically. So do not crank it. And having started, don't trust it: that fuel system is wearing down while you drive.
- Leave your ignition be also. Diesel does two jobs: it combusts, and before it burns it protects that high-pressure fuel pump and the injectors. Petrol manages the first but not the second. Switching the ignition on is commonly enough to prime that system, which moves the petrol out of your tank then into exactly those parts.
- Do not pour diesel on top to weaken it. A diesel fuel system will not accept petrol by percentage as that advice presumes, and topping up clears nothing — it merely leaves you a bigger tank of the same mix. The type makes no difference either: super unleaded is just petrol.
- Remain where you are if you reasonably can. A vehicle that hasn't shifted is the quickest one to sort out, and we'd sooner come to an odd spot than have it started. If you are stopped on the verge on Poles Lane, switch the hazards on and keep it there.
- Before you phone, gather your whereabouts. Anything next to you with a name on it, plus a postcode starting SG12 0 — that is what determines whether our van shows up or circles.
- Phone 0333 366 0103. Anticipate three questions — what got in, approximately how much, and whether the motor has been started. Your responses determine whatever comes after.
Can petrol be drained from your diesel at a forecourt?
It starts at a pump, mostly. Quite often it wraps up on site as well. Still at JET? Then that is usually where it happens. Petrol station forecourts are routine for us, with the consent of the site.
The forecourt is the one location this gets spotted before the motor has run. Fuel pulled out of the tank and through the filter, right to the high-pressure fuel pump, is what occurs when your engine is fired up and your car is driven to where it is now: the car park, the driveway or the lay-by, anywhere other than the forecourt. So the flush includes the filter and the fuel lines together with the tank. That's still not a calamity, and we sort it out where the car stands. What decides it is whether the ignition was reached for in the seconds after your receipt was read.
Out from the petrol pump, the next motorist can get by — so yes, let the staff help you move it. Very much worth doing. Four vehicle lengths is not worth the risk.
How much fuel your pump has sucked is what we are really asking — not how long ago any of that was. So the enquiry we hope for goes like this: diesel Volkswagen Passat, some litres of unleaded, a couple of miles driven, now shut off outside Asda.
Your diesel BMW 3 Series will have felt completely ordinary on the way back from Thundridge Church of England Primary School. They do, and that is the trap with petrol in a diesel instead of the other way round. Put diesel in a petrol car and it mostly will not run, so the driver stops and the wear stops with them. Put petrol in a diesel and it fires up, idles and pulls away as though nothing has happened — all the while the high-pressure pump keeps working without the protection the fuel is supposed to be providing. Nothing tells you, because from the driver's seat there is nothing to caution you about. Phone us with about how far you travelled and how hard you pushed it; the second answer matters more than the first.
Clearing the Peugeot 3008, changing the fuel filter where there is a serviceable one, purging the fuel lines, putting clean fuel through the full circuit: that's the job, and it is shaped by the worst of that sitting in the fuel lines instead of in your tank by this point. Three things help when you phone from near St Mary — which side the filler is on, whether a van can pull up beside without blocking the road, and whether the motor has run since you filled up. On-street is the most common place our engineers work, so the location itself is hardly ever the problem. A cramped parking space is better than a motor driven somewhere more handy.
Hire car or company car? Call them before you phone us — some agreements want the hire firm to approve the work, and sorting that out first is a great deal quicker than sorting it after that. Then phone us about the Mercedes E-Class by Thundridge Village Hall, and don't worry that you cannot say how full the tank was. Almost no one can, in a vehicle they collected two days ago, and we work it out on site. The reason our technicians ask is that petrol in a diesel does its damage as a ratio: the same few litres in an almost empty tank is a far stronger mixture 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 that mixture, the more it rattles, smokes and goes flat.
No dashboard light exists for this, which is why motors in that position usually get driven again before anyone calls. Don't be one of them. The throttle went soft and your idle turned uneven after a few streets, and the diesel Audi A3 is now resting close to First turnpike house. Deadness there means fuel that cannot build pressure fully rather than an engine failing. Switch off. Phone us.
Coverage in Thundridge
Wadesmill, Cold Christmas, High Cross, Ware, Tonwell — each of these on our trips that bring us across to Thundridge as well, a village.
Not on this list? That means nothing. The names above are only the closest few, and nearly all places around Hertfordshire have a page of their own elsewhere on our site. Guessing is the mistake to avoid, above all on a border or somewhere a satnav fails. Call us and check.
Look at our map for the area covered here. The lot is territory our engineers cover: a kerbside, a forecourt, a drive, a car park. You never bring the car anywhere.
Roadside call-outs around Thundridge
Some people find no suitable spot to pull in at all. Hazards flashing in a lay-by somewhere, or pulled onto the verge beside Cambridge Road because you worked it out after setting off — we take that call often enough that it's the normal kind.
Whether you sit beside the vehicle or step clear of it turns on if being nearby looks wise. Never restart it to get to a safer place. It will go — a diesel on petrol normally obliges — and each mile of obliging drags the mix deeper into your fuel system. Driving on does your car far more harm than a van heading out to an inconvenient location, and that is no bother for us.
Already run it? Petrol in a diesel over some miles
Your A1(M) is the one that counts here, and it runs under 10 miles from Thundridge. It will frequently take you onto it, and some way along, before you notice a thing. Then it's some smoke, a lumpy idle and power ebbing away — not a clean stop. Wrongly fuelled diesels rarely give you one of those.
Don't start it to move it. Come off at the next sensible exit then turn off. On a longer trip — anything near the under 15 miles to the nearest city — assume the petrol has been through the fuel filter, your pump and the injectors, and tell us when you phone. It affects what our engineers bring.
Thundridge itself
Thundridge is a village in Hertfordshire, situated on the riverside at an elevation of 79 metres, with semi-detached housing being the predominant type. Thundridge lies near the villages of Wadesmill, Cold Christmas, and High Cross, and is approximately 14.3 miles from St Albans. Thundridge is also within commuting distance of London, being around 22.9 miles from the city. Thundridge has a population of around 834 residents.
What comes next when we reach you in Thundridge
- Our engineers find out what got in, how much, and whether the engine has run. The responses alter the work, which is why our engineers ask before giving a price.
- Out goes the polluted fuel.
- Fuel lines are flushed through and your filter cleaned, leaving nothing in your system that caused any of this.
- New diesel goes in, and then your system gets primed.
- The motor is fired up and tested to make sure it runs properly on clean diesel.
The vehicle is then ready for you to drive away. Permanent damage is very uncommon when it has been caught quickly, and since all of this is done where the vehicle is, it never has to go to a workshop.
AdBlue in your diesel tank by mistake, in Thundridge?
AdBlue rather than petrol? Then the opening instruction is unchanged — the engine stays off — while this issue under it's a different one altogether. Weakened diesel, and no protection left for the system that depends on it. That's petrol. AdBlue is urea dissolved in water, and in a diesel tank it brings rust and residue in its place.
Both are ours. There is a separate Thundridge page for AdBlue removal, with the full story on it — including the reasons it frequently turns out to be the worse of the two.
Thundridge prices for a petrol-in-diesel fuel drain
One price would not be honest here, as this is not one job. These are the things that move it:
- This is the key one: whether your motor has been run, or driven.
- The tank's capacity, set against how much of the wrong fuel got into it.
- Whether it was unleaded or AdBlue.
- Where the vehicle is, and if a technician can safely reach and work on it.
Tell us your car, the quantity and whether it has run, and you'll get a firm answer rather than a range. Motor at home, going nowhere, nothing pressing about it — is good for that.
Petrol in diesel: everyday questions in Thundridge
Fuel drains on a Thundridge petrol station forecourt
Yes — forecourts are where a good share of this takes place. Tell us which one you are at when you phone and we'll tell you whether our technicians can work there. With the station's agreement our engineers attend Esso and the other forecourts nearby routinely.
How much petrol is too much for a diesel?
Litres are not the measure. Ratio is, and far more than either, it counts if anything has been run. Five litres in an almost empty tank is a different case from five in a full one — but either way, the thing that settles how much work is needed is if that blend has been drawn through your fuel system.
Petrol in my diesel, and I have driven the car
Stop sensibly. Off. Nothing after that. Not restarting it is the single most useful thing available to you now. Driving does move the problem out of that tank and into the pump and injectors, yes, and it remains recoverable much more commonly than people fear.
Is a fuel drain going to void my warranty?
A drain and flush carried out properly is not a change and doesn't void a manufacturer's warranty. An argument over a warranty is likelier to come from running a diesel on petrol — so leave it turned 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 distinct fault. So no. Your tank still has petrol in it later, and the pump still has to live with it.
Does petrol in a diesel have to go to a main dealer?
Wherever the vehicle is, we drain and clean it there, so a visit to the main dealer does not come into it.
Is your car still with you?
Your engine stays off.
Already driven it? Then stop somewhere safe, turn off, and let the vehicle remain that way. Cold, stationary, going nowhere: that's the best position to be in. Motorists fear this a lot more than they need to.
At the kerbside, on the forecourt or at home — call-out fuel draining around Thundridge and throughout Hertfordshire.