Wrong fuel?
We’ll get you back on the road

Wrong fuel? We’ll get you back on the road

Mobile unit available in your area now

Avg. arrival time 46 mins

We fix it while you wait: roadside, forecourt or home

Your car won’t run on the wrong kind of fuel. On top of that, it causes expensive engine damage. Petrol in a diesel car, or diesel in a petrol car are both bad. We come and fix the problem now, while you wait, so you can quickly get back on your journey with no harm done.

First, don’t start the car. If you’ve already driven, park up safely. Keep your engine switched off, and wait for our engineer

Symptoms of wrong fuel

Car refuses to start after refuelling

Loss of engine power after refuelling

Engine runs poorly after refuelling

Car won’t start when engine has cooled

White smoke in exhaust after filling up

Dashboard warning light after refuelling

What does wrong fuel do to my engine?

Petrol and diesel engines are very different, and they can’t run on the wrong fuel. Wrong fuel damages your engine by blocking filters and washing away lubricating oil. If you act quickly, it will be fine. We fix it on the spot so you can drive on without concern.

We bring specialist equipment to remove the wrong fuel safely – including flushing your fuel lines, filters, pumps and engine. The procedure to drain wrong fuel, then re-set and re-start your car takes about 30 minutes.

We’ll give you fresh fuel so you can drive on. Once done, your car will be just fine. Our mobile mechanic will be with you soon after you call.

We have a large fleet of mobile units that provide local service across the entire country.

Ireland’s biggest wrong fuel specialists, country-wide coverage

5-star ratings on Google, Trustpilot, Reviews.io

Trusted by insurers, fleet managers & hire companies

Put the wrong fuel in and driven it?

Your car might go a short distance on the right fuel left in the tank. But as the wrong fuel goes through the system it will do damage. It needs to be fully removed. There’s really no safe amount of wrong fuel. If you’re not sure, call our hotline for sensible advice.

It’s very easy to misfuel without realising it. Hundreds of motorists do it every day. If your car won’t start, or runs poorly after filling up, you can check your receipt to see what kind of fuel you bought.

If you’re not sure, call our hotline now for sensible advice.

Environment Agency accredited, fully compliant

APEX, Safety Passport, CARS, EcoStar Approved

Fully insured and fully equipped

Why choose Fuel Fixer?

Several companies now offer fuel draining services, including reputable businesses such as the AA and Fuel Doctor. Unfortunately there are also less trustworthy companies without the equipment and training for a proper job. We have over 15 years experience and lead the field in service and technical expertise.

In the unlikely event you experience a problem afer we finish, you’ll have our hotline number for further advice and help.

Once our mechanic finishes the draining he’ll do a re-set and re-start procedure – after putting in some of the right fuel. Then you can get back to your journey.

He may also advise using a special additive when you next refuel to give extra engine protection. If so, he’ll explain and show you how to use it.

Full after-service support and advice hotline

We may follow up for quality purposes

Full paperwork and VAT invoices provided

Want to know more?
See answers to common questions here

Many people ask: “Have I damaged my engine?”, “What exactly does petrol do to a diesel engine?”, or “Will this affect my warranty?”
See the answers below, or call us on 01 506 0386

Petrol in a Diesel engine:
Petrol and diesel engines are very different. Petrol needs a spark to ignite, but diesel combusts slowly under the pressure created inside the engine.
Diesel is thicker than petrol, and more oily – diesel engines rely on this oiliness for lubrication. Petrol washes that oil away, leaving the internal components open to rapid wear.

Diesel in a Petrol engine:
Diesel in a petrol engine doesn’t ignite or burn.
It can drain down into the car’s oil sump, which can become overfilled and – potentially – cause catastrophic engine failure.

Further damage can result from the thicker diesel blocking fine fuel injection components.

Petrol dissolves the rubbers used in hoses and seals in diesel engines. The right-hand picture shows mixed fuel removed from a diesel car just 24 hours after misfueling. On the left is unmixed fuel.

Have I damaged my car?

Provided you act quickly, you’re very unlikely to suffer any serious damage. In the great majority of cases the car will be up and running again as soon as we have drained the wrong fuel from the system.
It’s best if you haven’t started your car, as that means there’s virtually no chance of damage. Even if you have started it, and maybe driven for a bit before noticing something was wrong, the chances of any lasting damage are slim. If you somehow managed to get home but then the car wouldn’t re-start, you’ll still be fine – but call us and get the wrong fuel removed as soon as you can.
However, the longer the wrong fuel remains in your tank, fuel lines, and engine, the more damage it will do. Left alone, it will gradually corrode rubber and plastic seals and tubes, and dissolve lubricating fluids.
It’s not advisable to continue to try and start the car, or to leave the wrong fuel in the system for any length of time. The simple fact is that petrol cars need petrol, and diesel cars need diesel. Anything else invites problems.

I drove a couple of miles after filling my diesel car with petrol. Have I done any damage?

The small amount of unmixed diesel that remained in your fuel lines, and the slightly mixed fuel in your tank can carry you a short distance.
But once the petrol has traveled through the low pressure sender pump, then the fuel lines, up to and through the filter (which holds about a pint of fuel), through the hoses to the high pressure pump, thru the pump, into the common rail reservoir, and finally through the high pressure lines into the combustion chamber – that’s normally the exact point that the engine stops turning. This is what happens if you put petrol in a diesel car. Petrol in a diesel system is bad news – it removes engine lubricants and corrode seals.
For these reasons, the because you likely want to finish your journey and continue using your car, the wrong fuel needs to be removed fully.
In the old days you could siphon petrol out of your fuel tank by sucking on a length of hosepipe but, besides the taste being quite evil, modern fuel tank designs make this unfeasible. It takes specialist equipment and expertise to do the job properly now.

What does petrol do to a diesel engine?

The pictures here show the condition of two hoses that were used to empty misfueled diesel tanks. In both cases the mixture was more petrol than diesel. They show what happens to the plastics in your fuel line if exposed to mixed fuel over a day.
Left: After petrol/diesel mix was removed within an hour. The hose is still clear. Right: After petrol/diesel mix was allowed to remain in the system for a day. The hose shows black fluid, caused by rubber from hoses and seals dissolving in the petrol.

What happens to the mixed petrol/diesel removed from the vehicle?

An environment agency licence is required to transport and store the mixed fuel we remove. It has to be securely and safely stored and is then ultimately re-refined and returned to the fuel supply chain.

What’s worse: Petrol in a Diesel car or Diesel in a Petrol car?

Both are bad news.
In small quantities, and depending on the individual engine design, wrong fuel does different things in petrol and diesel engines. In the short term, petrol in a diesel will usually stall the engine. Depending on the mixture, it might just still run but with reduced power and sounding like a bag of spanners. Diesel in a petrol car will make it lose power, and run flat.
The worst case scenarios (and these are the WORST) are:
1) Petrol in a diesel pump will eventually damage the pump by corroding rubber an dplastic compoments and by removing the oily lubrication that diesel fuel provides – If you are unlucky enough to get a mix that just runs. You would also have to do a fair amount of driving with a heavy foot, and be oblivious to the car’s behaviour. The same issues would sooner or later require replacement of: common rail pump, piezo injectors, fuel lines, and high pressure fuel pump (this last operates at around 28 thousand PSI of pressure and is a highly engineered, relying on passage of diesel for its lubrication. Petrol does not lubricate – in fact it dissolves the oils in diesel – hence petrol is good for cleaning out oil stains. No lubrication means metal grinding on metal in a high pressure environment. The metal chafe is then drawn thru to the piezo injectors and ruins them as well, and on through the cylinder linings. This level of damage is rare, but horribly costly.
2) Diesel in petrol worst case scenario: the diesel will enter the cylinder and not burn, it will slide past the piston rings, into the oil sump and therefore the cars oil system. It will then increase the oil level to a point that could cause total engine failure (mangled rods, bent pistons, complete block failure) – or the thinning of the oil can reduce lubrication to the engine leading to a full seizure, big end failure, and/or ruined propshaft. This extreme damage would not be an easy thing to achieve – the car would be very low on power and not running right, you would have to do a good bit of driving in it to achieve the above. But it’s not what you want going on under the bonnet.
In both cases, the cost of removing the wrong fuel is tiny in comparison – and you will meantime be driving around in a car that actually works.

My main dealer says I have to get it repaired in an official garage. I’ve heard of these repairs costing up to £10,000. Is that needed?

Sadly, some main dealers and “tooth sucking garages” look on misfuel cases as a winning lottery ticket. We’ve heard of people having their misfueled cars collected by main dealers from petrol station forecourts (cars that had not even been started, with only twenty pounds of wrong fuel added).
Entirely unnecessary replacements of very expensive components have then been carried out, at great expense and inconvenience. Hopefully, for the owners, the insurance companies picked up the tab. That’s fine until you lose your no-claims bonus, or it comes time to sell your car and have to explain why it needed so much major work.
It’s not economic for most garages to keep the specialist equipment we use to fully drain fuel from a car – many of them find it simpler and faster to call us to do the job.

Why don’t I just fill up the tank with the right fuel and let the wrong fuel gradually work its way out?

It’s not recommended, but yes you can try it. If it’s just a small amount of wrong fuel in a full tank of the correct fuel – yes, you might be OK. You’ll find the engine tends to run poorly, and you may well see some dashboard warning lights which will have to be cancelled at a garage. Also when you next try to start the car with a cold engine, you may find the engine won’t fire.
Having said that, what you risk is corrosion of rubber hoses and plastic seals, and possible damage to fuel pumps and engine components. Any of those are going to be fairly expensive to fix. Some will be very expensive.
Trying to dilute the wrong fuel in your tank is at best a gamble. Occasionally it might work, but the cost of filling up the tank to the brim, added to the potential damage, makes it a potentially expensive one. But it is very much hit and miss whether you will even be able to get the car going, or keep it going, or re-start it the next morning.
We’re reminded of the old saying: if you’re in a hole – stop digging.
Calling us to fix the problem fully, and get you properly back on the road, is still likely to be your best, and cheapest option.

Are there a lot of idiots like me who do this?

You probably feel like a muppet right now, but the best estimates suggest over 300,000 people a year in the UK put the wrong fuel in their car. The pumps look similar, you may be distracted, you are in a rush… there are plenty of very valid excuses you can give yourself. We do get a lot of calls from mums with toddlers in the car, but we also get plenty from professional gents who practically live for their cars. Not to mention the occasional tanker driver, ambulance, or taxi driver. And then there’s the boat owners who filled their huge tanks with the wrong fuel. So all we can tell you is you really are not alone.
We’ll do our best to deal with your problem very quickly, and let you put it in your rear-view mirror.

Does petrol float on top of diesel, or the other way round?

Neither. They blend very rapidly in the tank and it becomes a fairly even mixture, although they are different compounds. They both come from crude oil, and spend millions of years in the ground as part of one and the same thing. Technically speaking, the carbon chain in diesel is longer, but only refining separates them out, and once recombined they will mix and stay together until re-refined.

Didn’t lorry drivers in the old days put a little petrol in their diesel tanks to keep it fluid in cold climates?

Yes, this used to be common winter practice until about the 1970’s. Petrol does indeed work as an ad-hoc winter fuel additive for diesel in remote and freezing areas, such as the Arctic.
However diesel engines in those days were low-tech brutes. They didn’t have things like the high-pressure pumps that make today’s diesel engines smooth and efficient. Today’s engines are snowflake prima donnas by comparison.
In any case, Winter Fuel Additive is now standardly added to our supplies of diesel by the refiners as early as September, so there’s no need to try the old home remedies.

My engine management light has come on. What does that mean?

Your Engine Management light can signal a variety of problems, small or large. The Engine Management computers themselves are not very informative: they either say – “no problem” or “problem”. Petrol in a diesel car will often confuse them. They are designed to regulate things like air and fuel flow, air pressure, exhaust pressure, exhaust temperature, ignition timing – all to give optimum performance, economy and emissions.
The wrong fuel throws all that complicated measurement and computation off. Some very intelligent engine management units will try to “adjust” to the contaminated fuel, and when they fail to do so (as they always do) they will throw up a fault code which or may not be accurate.
The vast majority of fault codes generated by a wrong fuel scenario are temporary – once the engine is getting the right fuel, they will switch off. It is very rare that a light stays on after a fuel drain and restart, but our specialist engineers tend to know any peculiarities there may be for your make and model and will give you the best advice for your circumstances.

Do I need to get a new fuel filter?

No, you not need a new filter to correct the effects of misfueling. Some garages assume that the filter will be contaminated with condensed amounts of wrong fuel and thus continue to weep wrong fuel into the system. In fact a filter does not hold much fuel, and petrol and diesel certainly do not “condense”.
The filter is simply a housing with a cardboard/paper filament to catch solid debris. It also has a water trap to stop water going into the engine. It needs to be emptied on servicing, or by dashboard warning light sensor.
Diesel and petrol do not “sit” in a fuel filter. When a fuel drain is performed of a car to remove wrong fuel, the filter is a flushed (by pumping the correct fuel through the filter to purge it).
A note of caution: We’ve occasionally seen hyperinflated garage bills for replacing a fuel filter. In fact they cost a few pounds, and take a around 6 to 8 minutes to change.

Can’t I just syphon the wrong fuel out by sucking through a bit of hosepipe?

This used to be possible, and on cars older than about 30 years it still is – if you don’t mind the taste of diesel in your mouth for a week. And older engines were more tolerant of bad fuel, so it was less critical that the wrong fuel was thoroughly removed.
But today cars have things like anti-syphon devices to stop the hosepipe reaching the fuel, and saddle-shaped fuel tanks with internal baffles which a normal hosepipe can’t get into.
It took quite some ingenuity and persistence to devise the specialist equipment we now use to do the job.
There’s also the problem of getting rid of the mixed fuel. It can’t be legally dumped down the drain, and it’s of no other use. We collect it in approved storage areas and then send it back to the refinery.

What if my fuel is contaminated with something else, like water or another liquid?

The symptoms of contaminated fuel are similar to wrong fuel – in fact wrong fuel is really just a type of contamination. The cure is the same: fully drain out the wrong or contaminated fuel from the tank and fuel lines and engine, do any engine management reset needed, and fill up with the correct fuel. e deal with all of these peoblams daily.

I put some AdBlue into the diesel tank by mistake. Will that cause any damage?

Yes. It can happen very easily because the fillers are usually next to each other. And many people have the mistaken idea that AdBlue is type of fuel additive. It isn’t.
Adblue is one third urea (acidic) and two thirds deionized water. That acid solution gets passed through your engine along with the fuel – with predictable results. Starting the engine will make the problem worse.
AdBlue helps to remove nitrous oxide – a poisonous gas – from your car’s exhaust. It is used to clean exhaust fumes. It works to convert nitrogen oxide emissions in the exhaust gas of diesel engines, into nitrogen and water. A particulate filter then further reduces solid particulates from the vehicle’s exhaust emissions.
Furthermore it is prone to crystallisation, clogging injectors and fuel filters.Fuel filters that have had AdBlue put through them decompose and fall apart, like cardboard soaked in water. It happens quite fast.
The acidic urea and paper particles clog up and attack seals, fuel lines and injectors. It needs to be removed quickly, preferably before the engine is turned on.