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Bugger, Bugger, Bugger - petrol in a diesel
nick205 - 10/9/12 at 09:56 AM

Feeling a total idiot! Manage to put petrol in my diesel Passat yesterday

Unfortunately I drove it a few hundred yards before it konked out so petrol right through the system. It's being sorted this morning by my usual garage so fingers crossed for no lasting damage.

Numpty sticker firmly attached to forehead for the next few days

RichardK - 10/9/12 at 10:02 AM

Should be ok, it's the other way round when bad things happen.

Cheers

Rich

phelpsa - 10/9/12 at 10:04 AM

quote:
Originally posted by RichardK
Should be ok, it's the other way round when bad things happen.

Cheers

Rich


Really?

Petrol in diesel causes fuel pump and injector issues, the other way round just causes a lot of smoke in my experience!

MikeRJ - 10/9/12 at 10:10 AM

quote:
Originally posted by RichardK
Should be ok, it's the other way round when bad things happen.

Cheers

Rich


No it isn't, petrol in a diesel is far worse than diesel in a petrol.

jollygreengiant - 10/9/12 at 10:15 AM

quote:
Originally posted by MikeRJ
quote:
Originally posted by RichardK
Should be ok, it's the other way round when bad things happen.

Cheers

Rich


No it isn't, petrol in a diesel is far worse than diesel in a petrol.


Correct there. Unleaded, even a small amount, nadgers up the seals in the fuel line, eventually leading to, worst case scenario, injection pump failure.

zetec - 10/9/12 at 10:29 AM

Depends on the system used. My old Ford Focus TDDI went 5 miles down the motorway before dying. System flushed out and still nothing wrong 30K later. Something said for old tech diesels.

emwmarine - 10/9/12 at 10:32 AM

quote:
Originally posted by jollygreengiant
quote:
Originally posted by MikeRJ
quote:
Originally posted by RichardK
Should be ok, it's the other way round when bad things happen.

Cheers

Rich


No it isn't, petrol in a diesel is far worse than diesel in a petrol.


Correct there. Unleaded, even a small amount, nadgers up the seals in the fuel line, eventually leading to, worst case scenario, injection pump failure.


Don't agree. People used to put up to 10% petrol in diesel in winter before winter diesel additives became more effective.

My good lady put 15 quid worth of petrol in our diesel disco. Having then filled it up fully with diesel it drove a bit smily but was ok. Ran for another 100k ok.

But even a small bit of diesel in petrol will kill the injection system and the Cat if it gets through.

RichardK - 10/9/12 at 11:42 AM

I guess Nick will let us know who's right, I know I put about 2 litres of petrol in my octy vrs diesel early on in it's life but as soon as I realised I brimmed it with diesel and never had any issues.

Maybe I was lucky?

Cheers

Rich

chillis - 10/9/12 at 11:49 AM

Yeh I've done that er twice
Second time managed to get from uxbridge to dunstable before I even re-alised. Got me home but was V difficult to get started the next day.
Just drained it out and put fresh in but it was painful having to bin 30 odd litres of super unleaded!

D Beddows - 10/9/12 at 12:05 PM

quote:
Originally posted by RichardK
I guess Nick will let us know who's right, I know I put about 2 litres of petrol in my octy vrs diesel early on in it's life but as soon as I realised I brimmed it with diesel and never had any issues.

Maybe I was lucky?

Cheers

Rich



Naaaah I've done exactly the same with my Golf PD TDI (only I put just under 6 litres in), did exactly the same as you afterwards and kept it brimmed for a couple of weeks - 10,000 miles later it's never even hiccuped.

nick205 - 10/9/12 at 12:05 PM

Garage just called to say all OK - PHEW!

Had to take the low pressure pump out of the tank to get the fuel out, but a full flush through showed no debris in the system and it's running perfectly. Fuel filter replaced as a matter of course.

Off to collect now!

BenB - 10/9/12 at 12:29 PM

I think people panic too early. My mate filled up his (almost empty) Transit Connect diesel van with RON95 and drove all the way from Leeds to London! Wouldn't start after switching it off- presumably the sparks weren't doing much and it was just dieselling on the petrol. A quick drain and all was good. No signs of problems even a year later when he sold it on.

ian locostzx9rc2 - 10/9/12 at 01:17 PM

Modern Common rail diesels dont like it have seen loads of car which are drained correctly new filters fitted etc then 3 to 6 months down the line high pressure pumps destroy themselves and metal filings deposit all through the fuel system ...

nick205 - 10/9/12 at 03:47 PM

Mine's a PD (pre-common rail) motor so hopefully less sensitive in this respect! It seems to be running OK, but time will tell.

MRLuke - 10/9/12 at 04:02 PM

quote:
Originally posted by ian locostzx9rc2
Modern Common rail diesels dont like it have seen loads of car which are drained correctly new filters fitted etc then 3 to 6 months down the line high pressure pumps destroy themselves and metal filings deposit all through the fuel system ...


Isnt that why you have a fuel filter?

MikeRJ - 10/9/12 at 04:04 PM

quote:
Originally posted by emwmarine

But even a small bit of diesel in petrol will kill the injection system and the Cat if it gets through.


Sorry but this simply isn't true. Too much diesel will certainly stop a petrol engine from running, but it's is extremely unlikely to cause any permanent damage to the injection system. Enough petrol in a common rail diesel is almost guaranteed to cause expensive damage if not caught very quickly, since the high pressure pumps rely on the lubricity of the diesel to work.

ian locostzx9rc2 - 10/9/12 at 04:50 PM

Fuel filter filters from f/tank only high pressure pump goes directly to injectors so if pump drys out due to petrol in system the damage is done!

StevieB - 10/9/12 at 05:03 PM

quote:
Originally posted by emwmarine
quote:
Originally posted by jollygreengiant
quote:
Originally posted by MikeRJ
quote:
Originally posted by RichardK
Should be ok, it's the other way round when bad things happen.

Cheers

Rich


No it isn't, petrol in a diesel is far worse than diesel in a petrol.


Correct there. Unleaded, even a small amount, nadgers up the seals in the fuel line, eventually leading to, worst case scenario, injection pump failure.


Don't agree. People used to put up to 10% petrol in diesel in winter before winter diesel additives became more effective.

My good lady put 15 quid worth of petrol in our diesel disco. Having then filled it up fully with diesel it drove a bit smily but was ok. Ran for another 100k ok.

But even a small bit of diesel in petrol will kill the injection system and the Cat if it gets through.


Yep - I did pretty mucht he same thing in Penrith once then brimmed it with Diesel once I'd realised my mistake then drove it home quite nicely to York without problems (I stopped again at Scotch Corner and filled it up again with Diesel to thin it out more).

If I'm honest, it actually drove a little bit better with the petrol mix, and certainly did another 50k without any issues.

Fatgadget - 10/9/12 at 05:12 PM

I thought it was impossible to insert a petrol pump nozzle into a diesel tank nowadays?

Davegtst - 10/9/12 at 05:45 PM

quote:
Originally posted by Fatgadget
I thought it was impossible to insert a petrol pump nozzle into a diesel tank nowadays?


Hell no, it's how i make my living. Puttting diesel into a petrol is alot harder due to a diesel nozzle being wider than the petrol one but it still hapens. I've done 4 cars today, keep em coming



Fuel contaminations

Dave Ashurst - 10/9/12 at 07:16 PM

I don't know why but my petrol car runs noticeably better with a dash of diesel in the tank.

NS Dev - 10/9/12 at 07:58 PM

friend of mine put petrol in his common rail diesel, tank almost dry before he put it in..............it made it about 2 miles, said he wondered why it cut out a couple of times.........

new high pressure pump required, I saw the innards of the old one......... absolute scrap.

[Edited on 10/9/12 by NS Dev]

JoelP - 10/9/12 at 08:05 PM

I was stood at the pump once cursing it because it wouldnt go in That was shortly after i went back to petrol after years of diesels. Very lucky near miss!

SteveWalker - 10/9/12 at 08:42 PM

quote:
Originally posted by Fatgadget
I thought it was impossible to insert a petrol pump nozzle into a diesel tank nowadays?


No. Diesel nozzles are the same size as leaded petrol ones used to be, so it is perfectly possible to put the smaller unleaded nozzle in by mistake.

I think you can buy something that fits into the nozzle and prevents a nozzle being inserted unless it is big enough to operate the release mechanism.

nick205 - 10/9/12 at 08:49 PM

quote:
Originally posted by Davegtst
quote:
Originally posted by Fatgadget
I thought it was impossible to insert a petrol pump nozzle into a diesel tank nowadays?


Hell no, it's how i make my living. Puttting diesel into a petrol is alot harder due to a diesel nozzle being wider than the petrol one but it still hapens. I've done 4 cars today, keep em coming



Fuel contaminations



Interesting.

As someone who deals with this professionally can you comment on experience of likely/possible long term damage?

Car in question is a 57 plate Passat 2.0 TDI PD, no DPF. It was driven 2-300 yards out of the filling station before it died. First thought was I'd stalled it so tried re-starting, but immediately obvious it wasn't going anywhere so pushed/towed from there. The fuel light had just come on and I brimmed it with unleaded at 3pm Sunday. It was drained and cleaned 10am Monday.

Davegtst - 10/9/12 at 09:18 PM

You will be absolutly fine. I hear the scare stories about this all the time, most of it coming from garages who haven't got a clue what they are doing and replace eveything just to be sure. I once phoned my local Honda dealer up with a bogus misfuel just to see how much they charge and they told me i would need a complete new engine, pump, injectors and even a new tank! There is so much bs people will tell you i could be on here all night. It's a shame i didn't know about your passat earlier, i could have told you how to do it very easily.

dinosaurjuice - 10/9/12 at 09:19 PM

modern diesel is very different to old diesel. and modern diesel injection systems are very different to new ones.

petrol kills a diesel in 3 ways (generally). not usually all, but at least 1 will give problems.

Reactions with the seals and various rubber components used in pumps and injectors.

Lack of lubrication (this is the biggy) to modern vane pumps and CR injectors.

Heat! Burning petrol in a lean diesel engine makes them hot, can destroy turbos or valves etc. Not so common, takes a while.

Never done it myself. Have been stopped by people twice when filling kitcar with diesel