Putting Petrol into a diesel's oil system

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Hi im just wondering if anyone nows of some one or has themselves put petrol into a diesel oil system. my sisters car developed a fault after a drive to cornwall and her boyfriend phoned one of his mates (instead of me or the aa) and they decided it was a blocked oil strainer in the sump, he was then told he should pour petrol into the oil system to what i can only assume to act as a thinning agent. im now wondering if i can expect any problems from this. Its not an idea im familiar with any advice on this would be great thanks in advance

Mike

Hi

Sounds like a recipe for disaster. a diesel engine will normally tolerate a 5% dilution of the engine with diesel, after that things get critical. Petrol is a finer spirit and is a good if volatile cleaning agent and shouldn't be used to thin oil down, you also run the risk of having a gaseous explosion in the crankcase (this might just blow the dip stick out or split the sump, worse case you'll be making a claim on the F part of the TPF&T section of the insurance.

What were the symptoms of the fault that necessitated such drastic action?

Regards

Stuart

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Basically I replaced the turbo on her focus (the retaining nut inside the turbo came off and mashed the fins) over 500 miles happy motoring later all fine until she was 5 miles from her destination in cornwall the oil light came on. they got to there destination shut the car down checked the oil levels all was fine. they came to start it back up and it wouldn't start apparently it was putting out blueish whiteish smoke at 1st he thought the number 3 injector had melted wasn't the case he rang a mate n between the two of them they decided something in the oil system was blocked hence trying to thin the oil with petrol. how they came up with the idea i dont now. he managed to start it eventually but ran like a dog but now all seems fine. I managed to twist her arm call the AA no codes recorded so he couldn't do anything but im guessing they never gave the AA man the whole story. But its having the oil drained flushed and the strainer is been replaced tomorrow.

But I'm still at aloss as to why his mate would even suggest putting petrol into the system and judging by your posts they have been very lucky so far, just hope it hasnt done any damage :/

Thanks for the quick replies all help muchly appreciated

Its an old military trick but its parrafin not petrol so they got their wires crossed. It thins the engine oil and acts like a deturgent. Its what they used to do to de-coke dirty multi fuel engines in the field. It also stops the oil freezing in the sump when its really cold. A half a pint of parrafin to every gallon of engine oil. If petrol has been used as long as its flushed and changed it will not have done any damage to the engine. Its like having an OMD oil in it for a short while.

A wee bit of diesel maybe, as it has detergent in it, but petrol doesn't sound like a good idea as it would wash the oil off the cylinder walls under the pistons.

petrol is definitely a no no if you get a miss fire and it blows past the rings or the valves it could cause the engine to go with a bang

this happened to my mates frontera after it ended up with petrol in the oil this just blew the rocker cover to bits but it could just as easily been the sump

I take it it was a 1.6 Focus?

This is a common failure of the turbo. Unfortunatley its not just a simple swap the turbo job.
You need to replace oil feed and return pipes, drop sump and clean out/replace, Change oil pick up pipe, change oil and filter, measure oil feed to turbo, run engine, change oil and filter again, check oil feed again....and if all checks out ok then road test. Then remove oil return pipe from turbo and re check for metal filings in oil, if ok release car.

If you just strap on a new turbo, engine will usually fail within 500 miles....been there, done it, cost us a turbo, but we saved the engine. Had two others that we couldn't clear the metal filings....they needed engines. At least one other dealer down here missed the Ford instructions and got caught for two turbos' and an engine.

My advise...avoid 1.6 focus diesel...the later ones with DPF need the DPF fluid topped up every 37500 miles and the Filter itself replaced at 75000 miles....at cost of circa £800....again if this isn't done the engine will fail, and 80000 isn't a high mileage for a diesel.

the 1.6s arent bad any more. used to see a lot more of them than i do now (ford Tech) they seem to have removed the additive system on the new ones too

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Rich that is some nasty damage still having trouble convincing my sister and her boyfriend how lucky they have been. Spoke to her today and unfortunatly shes convinced it was the right thing todo :cry:

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Meooo yep it was a 05 1.6 focus and my 1st turbo change had to change the oil feed pipe. According to my local part supplier with her model focus theres a few different turbos on their system the original turbo was a mitsubishi part and the original pipes had to be changed, but other than dropping the sump amd cleaning the internals of that out i did everything else mentioned, inspected the oil filter on the last of the oil changes clean as a whistle.

I had been told that the 1.6 focus had problems with sludge collecting in the turbo oil feed and return pipes leading to the turbo failing hence the change to the original pipes.

found the offending nut stuck in the air pipe connecting the air box to the turbo but will now be keeping a very close eye on the car from now on and will be getting a very close inspection when it gets back

thanks for all the feedback on this potential disastrous situation

Its not sludge thats the problem, its metal filings from the initial turbo failure. There is a filter in the oil feed pipe to the turbo you have to change also, as well as the feed pipe...