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New to the forum and I come in search of help - Petrol in a Clio 1.5dci

  Clio 1.5 dci
I'm new to the forum and have come in search of some help. And I am not sure if this is the correct place to put this, searching didn't bring up the answers I was looking for so with my introduction comes the questions.

I have a Clio 1.5 dci from 2005. It's been kept in fair condition and to this point it's been fairly low cost to keep it maintained, last year probably saw the largest bills as we had an overheating issue and ended up getting the head reconditioned, new water pump and radiator + labour, still it wasn't too crazy. We've just changed the engine mounts, shocks disks/pads, steering boot and track rod ends as part of general maintenance. With just over 289,000KM it's been a little legend to this point.. So onto the reason I require help..

Last wednesday on my way home with the fuel reserve light on I stopped to fill up the tank. Having filled up I headed on my way, my house is exactly 8KM from the petrol station and at KM 7 the car started running rough and then flashed all the lights on the dashboard including "STOP". At that moment I realised, I'd put in unleaded.....I managed to coast (engine running) to my house where the car is now.

So having siphoned the petrol from the tank I was thinking to top it up with 10 ltrs of diesel, use the fuel line primer to pull through the diesel and get rid of any petrol in the system. Then connect a new fuel filter (which I already have as its the last of the routine maintenance to be completed this year). Clean the pipes from the filter to the pump and hope all would be good.

So my question is, if the engine was still running when I got home would the above be the correct way to do this, if not, I would rather know now that I have more work to do than kill the engine on start up.

Thanks in advance for you advice...


Absolute wetter.
ClioSport Club Member
You filled the tank with petrol? How much did you manage to syphon out?

You don't wanna start the engine with only 10L diesel in the tank, it's gotta be brimmed to dilute the petrol out as best you can.
  Clio 1.5 dci
OK more diesel can be found.

So far I have emptied the whole system not including the pump and injectors. The tank was syphoned to get the majority and then I pulled the remained through using the fuel filter primer pump so there is almost nothing left in the system. I was planning to put diesel back in the tank and then hand pump it through, clean the pipes from the filter to the pump and prime the system. Thinking this through while doing it leaves me with a concern, will that be enough. Or do I really need to remove the injectors and purge the pump or I still risk damaging the motor.

Petrol in a diesel is better than diesel in a petrol ;) :D lol

Jeremy Clarkson said on Top Gear that it's a total ballache if you run a diesel dry, because you have to faff with clearing air out of the system (or something like that??) so as mentioned above, if it's still running (a bit) then I'd brim it with Diesel and then fire it up.

That would dilute any petrol left in the tank to the point that it made barely any difference.

It sounds like you've got as much out as you can without creating major work for yourself, so I think you'd be safe to 'run the risk'. If it is not a major pain to hand pump some through and clear out any petrol in the pump/lines, though, then that would be extra helpful, but I'm not sure how you'd split the lines off the connectors without risking air getting into the system.

*NB: I am not a mechanic and am dangerous with a spanner, so value this post at the amount you have paid for it ;) :D


ClioSport Club Member
  Clio 197
It definitely isn't better to put petrol in a diesel. Diesel fuelling systems rely on the lubrication that the diesel offers. It can cause big problems if people have run them on petrol for a while without knowing.

Just go with R3k's suggestion. Fortunately you've only used it for a few miles and it was running, so I doubt any serious damage has been done.
You'll have ruined the fuel pump

The delphi pumps on the K9K require sulphur for lubrication, even modern diesel will wear out these pumps over time (because new diesels don't contain sulphur) if you don't run 2 stroke with your fuel. You may get your car running again but unfortunately, it will never be the same again mate :(

Darren S

ClioSport Club Member
Sounds like you've done a great job trying to rectify the problem already.

Probably worth a new fuel pump as per @Yorkshire Pudding above - at least it would negate it being an issue should the car still run poorly for a while afterwards?

I'd assume that once you've got the car fired up, leaving it to idle for several minutes would be much better than instantly jumping onto an A-road/motorway with it?
  Clio 1.5 dci
Thanks guys, great advice, it gave me the confidence to carry out the fix. I drained the fuel tank, it was full of petrol (such as waste)... pumped the remainder in the system using the hand pump next to the fuel filter. Replaced the filter, put a can of injector cleaner in the tank and added 20 litres of diesel and pumped the fuel through the system. Loosened the pipes feeding the injectors and cranked the motor to purge the final contaminated fuel from the pump. Retightened everything and after a couple cranks she started, left it running for 10 minutes and now it seems to be running sweet.