A mate of mine (no, really) put petrol in a diesel a while back. It’s a 2005 astra 1.7d. He had a quarter tank of diesel and added £20 of petrol by mistake. Drove the car another thirty miles (without problem) before stopping by choice. However, the car wouldn’t restart. Got it towed and drained and it seems to have been fine since (good few months). It seems he got away with it. Does this mean it’s fine or will it die next week? If it does damage, is it obvious or is it a ticking time bomb?

it’ll be fine.

probably…

It’s fine.

Would you buy a car with a history like that?

Would you buy a car with a history like that?

Would you know?

probly be fine if its been driven since with no problems since.
my mate did it, empty to full.
he got away with it, just cost him a tank of fuel and the filters.
while he was in the garage he found out there had been 4 other instances that week alone, all involving the exact same type of car (accord 2.2i-ctdi) his was the only one that didnt cost 4k to fix.
hed driven about a mile, stopped by choice because the engine didnt sound ‘right’.
so, if your mate has driven 30 miles it will probly be ok.

I doubt when selling it that would be mentioned, would you?.

Five seconds on Google gives us,

http://www.theaa.com/motoring_advice/fuels-and-environment/misfuelling.html

Diesel fuel pumps operate on very fine tolerances and are lubricated by the diesel fuel itself.

Petrol in diesel acts as a solvent – it reduces lubrication and can cause damage to the pump through metal to metal contact.
…
If the car’s still under warranty check with the franchised dealer regarding their advice and correct remedial action – running with even a small amount of petrol in the tank might invalidate the warranty.
…
Generally a small amount of incorrect fuel should not damage the engine as long as you have not started the car and top up fully with diesel.

If you’ve added more than 5 litres of petrol – Drain the tank and refill with diesel
If you’ve added less than 5 litres of petrol – Top up with diesel and run normally unless the manufacturer has advised otherwise

Cheers for the advice guys. I know about it because he told me when it happened. I still know now I’m considering taking on his car.

I’ve seen the internet advice that talks about the petrol stripping the lube but they don’t make it clear if running diesel again puts that back or if the damage is permanent but not evident straight away.

been there, done that, drain, replace fuel filter, pretend it never happened.

I’d check the price of a replacement fuel pump for an Astra before making a final commitment.

worst case you’ll know what you’re letting yourself in for.

bloke on here paid £1200 for a Renault diesel fuel pump so they can be expensive…

Would you know?

How many cars have we bought ourselves where this has happened in its past? Bet there is at least one.

As above- fuel filter and a couple of bottles of red-ex diesel cleaner.

cheers guys. The internet is full of scare stories of massive damage and huge bills but no one tells you if you know instantly or if it hits you months/years later.

Runnign diesel back in it will of course put the lubrication back, because the diesel IS the lube. However it will have been run for a time with less lubrication, which will have added wear to the pump. How much is anyone’s guess. There’s a pretty good chance that it’ll shorten the life from say 250k miles to 200k miles maybe, but the car might rust away by 150k for example. So it’s anyone’s guess 🙂

I think the ECU stops the car being started it it detects somethings wrong. Thats what mine did anyway. Had it drained, put fuel back in, carry on as normal.

I bet most diesel cars have had it done at somepoint!

That sounds interesting Horatio. I’d imagine that 1/4 tank of diesel being heavier than petrol would have been at the bottom of the tank and been more than enough for the 30 miles. Is it possible that the car was being clever and stopped anything happening before it did any harm? Would the ECU monitor anything in the tank or pipe wotk before the pump?

i’ll second that renault fuel pumps can be the best part of a grand and they have two.. one thankfully is much cheaper than the other. i used to manage a couple of PFS and wrong fuel was notified to us about twice a week, we had 12 pumps at each selling about 150k liters at each PFS per week so it happens but aint no big problem.
recovery services usually insist on taking you to a repairers and getting the full drain and flush treatment. worst case scenario was a petrol beemer that had a complete fill with diesel and was driven for 20 miles before stopping then a flush still would nt work.. the two yr old car was written off and we were presented with bill.. two short words sorted that out..

I too have done this (twice).
Modern Diesels, its the kiss of death due to common rail technology and higher pressures.

Older engines like the one you are talking about will be fine.
In fact my one has run smoother and had more power ever since.

My wife filled our diesel up with petrol when there was about 1/4 tank of diesel left. The car stopped working after about 50yds.

Had to get it drained and that was it, the car ran fine for another 10k or so until we sold it.

The guy who did it said DO NOT tell the dealer about it if the car is under warranty as they could use it as an excuse not to pay out if some thing later went wrong with the engine.

cheers all. This is acrually sounding pretty reassuring. No one has a story of doing this, thinking it wasa fine and then the car dying 6 months down the line which is my big worry.

Older engines like the one you are talking about will be fine.
In fact my one has run smoother and had more power ever since

probably due to the petrol giving the system a good clean! 😉

My dad did it about 5 years ago, drove it until it stopped running, towed to a garage. Garage didn’t drain the tank properly, he ran it until it stopped running again, tank drained properly…..his car has been fine since (he still has it).

Now that’s a reassuring post. Now tell me that turbos and dual mass flywheels never go wrong and I’ll be happy.

They don’t go wrong as often as you think! Turbos will die immediately though if you run the car low on oil and there isn’t enough oil to lubricate it. So keep an eye on the oil.

I’m always hesitant of buying (high value)things from mates in case they go wrong. If you did buy it and the engine packs up in a months time then it’s awkward time for you/mate.

I accidentally used the green pump a few weeks ago and put about twelve quids worth of petrol in .

Just filled it with diesel and chucked in a bottle of Forte diesel additive. No probs what so ever in starting or running. I’ve done this quite a few times over the years without any problem

Do agree though newer cars are much more sensitive to the point you’ve got to be careful which fuel additives you can use.

My mum has done it several times although has never put quite that much in. she topped it up correctly and then ran it but it didn’t run thorugh until it had properly diluted it all.

I appreciate the “buying from a mate” comment. In fact, I offered the same advice the other day. However, this chap is selling his car because he’s off travelling and then planning on relocating when he gets back. So yes, I can see the risk, but it’s a lot less of one.