We all know that putting petrol in a diesel car is not a good idea. Usually the problems are fuel system related like injectors not functioning or fuel pump failure. If you catch it in time, you can drain the entire fuel system, flush with diesel, drain again, change the fuel filter and then fill the entire tank with the correct fuel.

However, if you are unlucky enough to not catch it in time and the engine stops, don't think that just a drain and refill will do the trick. Even a small amount of petrol will change the burn temperature in the combustion chamber and you wouldn't know it. You car may run and you think you've got away with it, but the chances are you haven't.

We've seen a few piston melts recently and the story has always been the same; petrol.







This one was from a car that the owner hadn't noticed he was putting petrol in at the pump. The tank was 1/4 full and he put just over £20 of petrol in. He drove away and a few miles later the engine stopped. He called one of these 'wrong fuel' emergency call out firms. They drained the tank and put 20ltrs of diesel in with some sort of additive. They told him to drive slowly to the nearest fuel station and fill the tank right up. He did this and thanked his lucky stars.

50 miles later the engine started to make a strange noise while driving up the motorway. He kept it going to the next services somehow and the engine died as soon as it hit idle.

So, apart from not putting petrol in a diesel tank in the first place, make sure that if you use a 'wrong fuel' specialist, they know what the're doing and then, if you are VERY lucky, you'll have saved yourself a load of money having your engine rebuilt by us!

PS. A little tip when buying these cars; look in the filler cap to see if the yellow tag has been deployed. This would indicate that at some point a petrol filling hose has been in there!!! Joe

I was unfortunate once put 20£ of petrol in my 2.7 realised straight away before i left the garage so topped it up straight away with diesil drove sedately went down to 3 quaters and filled again did this for a few weeks ang got away with it and that was a few years ago

Is that the top of the piston that’s melted or something on the piston? Was the engine a write off or rebuilt....with new pistons.... 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

That is what's left of the piston! Joe

Looks more like what the facehuggers come out of in Alien! 2014 BMW 530d Touring, 2006 BMW 650i, 2018 Mini Cooper S

It’s got some life left....maybe not in an engine though. Good training aid or customer example.

Is the Con Rod shot too? 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

New rings, a quick polish up and it'll be fine

Seriously though, I would have never thought that incorrect fuel would have caused that. It begs the question then, are petrol engine pistons made from a different spec metal than diesel ones? They must be I suppose. Kev

MY2014 L405 RR Vogue SE 4.4 SDV8 in Corris Grey
MY2010 L320 RRS HSE 3.0 TDV6 in Stornoway Grey