Putting petrol in a diesel engine
 

A friend of mine has just put 9 litres of petrol into his new diesel Mercedes, then topped it up with diesel.
Will it be ok?
Thanks

how big is the tank?

60 litres maybe

depends on the pump,

some are more tolerant than others,

seat / vw non pd engines actually reccomend petrol in wiunter to aid starting

he,s dumped just over than 10% so he may be ok, best bet just kep it brimmed with diesel at every oppertunity and treat it gently...


if i recall my limit it 3 gals (approx 15ltr) max petrol to diesel

but if he,s that worried he needs to go to a garage,

i,m a brain surgeon ;) what do i know about cars :eek2:

Mart

If it's a CDi engine DO NOT run it. They run a high pressure injection pump which are prone to failure in this situation, the tank should be drained and all lines cleared.
If its an earlier setup with a mechanical fuel and lift pump you might be ok, the worst thing to happen is that it might run a bit lumpy until the petrol is out of the system.

HTH

He clearly needs one of those electronic gadgets that shout "THIS IS A DIESEL CAR" each time he opens the cap.

Yes. Assuming he bunged in another 70 or so litres of diesel. If you search in Gen Technical there was a useful thread about this a couple of weeks ago (it was actually diesel in petrol but expanded). dl

Hopefully there'll be enough diesel in there to maintain lubricity of the injection pump etc. He may want to get a lubricity additive like MIllers Diesel Power Plus (from Halfords) and add a double dose to the tank as an extra precaution.

With 10% petrol in the tank it's hard to say if it will affect reliability / cause the diesel pump to have an early bath.

But if the car's been run since, keep topping up with diesel, sling some MIllers in and keep fingers crossed.

Thanks for replies lads. Bit of a mixed bag. Personally I would run it, but I dont think he wants to take the chance with 65k of new Merc.

Just taken it down to have it all drained off. Expensive no doubt, if only for the fuel.

Daz

Think he's done the right thing -- it might have carried on fine with no damage but if it DID knacker the pump, a new injection system on a big Merc is gonna be approaching 10K ....

Apparently latest-generation Mercs prime the injection system when you plip the remote to open the doors, so if you have accidentally filled with petrol, even unlocking the car can cause the damage ...

This is from this article in the Telegraph motoring section: bear in mind this is really about filling the tank with petrol, not sticking in a few litres then topping up .... but it's interesting reading.

http://www.telegraph.co.uk/motoring/...7/mfdies27.xml

"But if a motorist who has used petrol all his or her life buys or borrows a new diesel car then uses the wrong nozzle at the filling station, costly damage can be done even before the ignition key has been inserted, because unlocking the doors also energises a diesel's fuel pump.

"That puts the fuel under pressure, ready for instant injection into the engine, which is why modern diesels start so quickly. The old-fashioned waiting time for preliminary ignition "warm-up" might appear to have been eliminated, but in reality it has simply been electronically absorbed into pre-driving procedures. It is a clever and convenient development but it comes at a price for the absent-minded.

"Petrol wrecks diesel engine lubrication processes and is particularly damaging to a diesel engine's costly, high-pressure fuel pump, which operates at up to 2,050bar (30,000psi). Petrol removes the pump case hardening and if a film of hardened metal disintegrates into swarf it will greatly harm or even wreck an engine's internal organs.

"At best, if the engine is not started or perhaps run only very briefly, the fuel tank and its internal pump, fuel lines, main high-pressure pump, fuel injectors and filters will all require removal, clearing and re-installation (which might include some renewal) at a cost of up to £7,000. At worst, several parts will need replacing, even the engine itself, at a potential cost of £12,000, or more for a top executive car.

In practice, misfuelling is widely excluded from motor insurance policies. And it is automatically excluded for a vast number of companies that insure their vehicles third-party only to avoid high premiums. They pay for their own vehicle damage repairs.



Some links:

http://www.telegraph.co.uk/motoring/...2/mferor12.xml

Blimey! What job does he do that pays enough for someone to afford a £65000 car but requires such a low level of intelligence?! I want some of that! ;)

LOL, Politician? :D

Banker? ;)

What diesel merc did he buy for £65k? You'd struggle to spend that much even on an s class. Unless it was a 25 tonne lorry of course :idea:

My gf filled our year 2001 vag 1.9TDi with £15 of petrol about 6 months ago. The car was near empty so the mix was pretty grim. It ran for about 10 miles before cutting out at a junction and refusing to start. The guy who picked up the car via our breakdown cover gave her horror stories about having to go to a 'decontamination' centre and bills upwards of £3000. She phoned me and I asked for the car to be towed to a m8's garage. A quick drain and flush, fitted a new fuel filter and all is well over 10K later.

The m8 says his garage does at least one car per week and he's only had to replace a fuel pump twice in the last year, both BM's.

:D:D

I must have had some time on my hands on that day LOL ;)

Car back from dealers same day.

Apparently they tested the fuel, and it was not worth draining for such a small amount of petrol (9litres). Just keep topping it up hence watering the petrol down.

Had figured it would be ok. In my handbook (Seat not Merc) it says you can actually put up to one third petrol into a diesel engine in case of being unable to find any diesel !

Wasn't sure how this related to new Mercedes anyway. But not too different in principal it seems.

I did wonder if it would seperate though..

Daz

Specced up S class 3.222 Diesel.

He was wise to take it to the dealers to check though.

Les

He would be wise to get a big fook off sticker on his filler flap too :)
DIESEL

you need to do this as a practical joke, and other stuff too lol

Credit to the dealers for not spinning the guy a ****ty one and taking more cash from him than was necessary.

Mind you as he was a customer who spends that kind of money on a car they probably thought wisely.

Nobody ever knows whether its a diesel you can tun on petrol or vice versa, its like the can you feed a cat dog food or the other way round !

9 litres of petrol in a 60 litre diesel tank will have made it run so f*cking hot (and thats nothing to do with the temperature gauge!) its untrue. Are the dealers competant?

id take it to a dealer and get them to flush the system imho!

if anything does decide to give up the ghost due to the mix . the warrenty or insurace wont cover it , and he will be lookin at a huge billl!