Petrol in ML270 Deisel

[Timchambola]

For all the idiots out there like me! Last week my fuel light came on and I only had a £20.00 note on me. Called into the service station and put £20.00 in (which took the needle to just under half). Drove home (1.5 miles). Came out to the car an hour later and it wouldn't start. Gradually through a process of elimination (and smelling the filler) it dawned on me that I'd put £20.00 of unleaded in! Rang Merc dealer and was told that I probably had ruined the whole thing and the last one they did cost £3,000.
I went and bought a small pump (fits on to a hand drill). Undid the fuel line from the fuel pump and attached it to a hose which was attached to the pump and then a large bucket. Pumped out 38 litres of fuel (until it ran empty). Put in a can of deisel and again pumped it through. Put everything back together. Started first time and has been perfect since. £3,000? Paaah!

 

[Uncle Benz]

I have had loads of customers do this, and after draining and filter change they have been fine. They say that the lack of lubricating effect of petrol compared to diesel can damage internals of high pressure pump, but I have yet to see it. Maybe if you do it regularly you may damage something but most people seem to only have the embarassment once !!!!!!!!!!!!!

 

[mioba]

The dealers think we the loyal customers are stupid and would happily pay 3K.
To be honest I doubt they would do 3K worth of work, probably like you a drain and refill, yet happily charge you the full wack.
Some pople put alot faith and belief in dealers who are clearly ripping us off.

 

[jberks]

The dealers do tend to insist everything is replaced on the modern CDIs but everything I have heard implies that in 90% of cases this simply isn't necessary. A friend of the wife fulled her new 2.8 cdi Jeep with unleaded. Ran it until it died. She rang me and I repeated what I'd heard - could be a £3k job. Like you, they drained it and refilled with diesel - it's run fine ever since.
I actually haven't heard of a single case where the anything more has been needed. I suspect its like many things, there is an official answer, and a real one.

 

[psmart]

As some of you are probably aware...

... I ran my ML270 on a 33% petrol mix quite happily for the Ski season, sub-zero temperatures, then autobahn storming in high 100's. True, Ive had to get the Turbo-Cat seal replaced and will probably change the Turbo in the not too distant future (due to it whistling out of the actuator bearing, even though Merc-Care insist it is 100% ok, just my nightmares over previous Turbo experience).

Some of the Germans and Austrians I mix with in Austria regularly mix in Petrol, even though there is an advisory by most manufacturers against doing this, they havent had troubles.... theoretics against pratical. Running Diesel at -30 (-40 or more with windchill) or a non-running car!

 

[Blobcat]

... I ran my ML270 on a 33% petrol mix quite happily for the Ski season, sub-zero temperatures, then autobahn storming in high 100's. True, Ive had to get the Turbo-Cat seal replaced and will probably change the Turbo in the not too distant future (due to it whistling out of the actuator bearing, even though Merc-Care insist it is 100% ok, just my nightmares over previous Turbo experience).

Some of the Germans and Austrians I mix with in Austria regularly mix in Petrol, even though there is an advisory by most manufacturers against doing this, they havent had troubles.... theoretics against pratical. Running Diesel at -30 (-40 or more with windchill) or a non-running car!

With non CDI diesels up to 25% unleaded was a recommended mix for winter use. With the advent of high pressure CDi Engines and Winter Diesel this is no longer recommended.

BTW many flags stuck on cars overthere at the moment?

 

[Sprint'n'Go]

A customer of mine put unleaded in his 2 year old diesel Kia Sedona and ran it till it died. It passed through the hands off 2 garages before the insurance company moved it to a specialist to do the full job and get it going again.

It cost around £4K to put it right and fortunately his was one of the few insurers to cover this as accidental damage.

This just goes to show that it does happen sometimes.

 

[psmart]

I probably wont try adding petrol again this year, the TDI club has put the willies up me with info, and as my glow plugs are all new and I never had starting issues in subzero temps before, no point pushing the envelope and causing unneccessary damage.

 

[martthefart]

Recently, 5th gear did a bit on this, running a diesel on petrol and vice versa. They made the same point about what a garage would say and the cost of job. They ran both untill they died, drained the tank and put the correct fuel in and they both ran with no apparent ill effects. In fact i think the diesel engine faired better than the petrol! The cars used were old and they suggested that modern CDi engine mght not fair too well due to the lack of lubrication in fuel pump and higher operating pressures/temperature.

Just goes to show...

 

[Tomkinsm]

I develop pumps for flammable atmospheres and have a warning: Just be careful with the pump you choose. Petrol vapours can be ignited by the sparking in electric drills. Petrol/petrol-vapour could also be ignited by failure of the mechanism inside the pump. £3k might sound cheap when you've blown up your car and burnt your face! Its only a risk, but it could happen.

Probably best to drain as much as you can by siphoning or hand pump, then filling back to full with diesel. As psmart has pointed out, a small amount of petrol in your diesel tank is fine.

 

[Hibbo]

Good for you Tim! Far too many people worry about far too much about the good old petrol/diesel mix-up chestnut. I read on this very site about someone who had put 60p (yes, 60 pence worth) of petrol in the diesel and was convinced their car was going to explode, even after everyone on here telling them that the engine wouldn't even notice such a tiny difference they still were on about taking it to the dealer for the 3 grand scam!

Good to see some people don't rise to the scaremongering!

PS. I was going to say 'some people have the common sense not to rise to the scaremongering', but that would be a bit of an oxymoron on this thread subject!

 

[psmart]

Popular belief is that petrol is highly combustible, which is true, but only in strict conditions. Hydro-carbons can soak up an immense amount of energy without detonation, ie. Common Rail in a Diesel engine without going bang. Petrol will only ignite in the correct air/fuel ratio, either in the presence of a spark because it has reached its flash point (>-43') or because it reaches its auto-ignition point (>300') but only in a correct air/fuel mix. Diesel figures are >55' for flash point and a similar figure for auto-ignition point.

Take a simple Eberspacher or other oil heater, which burns fuel by auto-ignition (at startup) by blowing it through a vapourising chamber onto a glowing cherry-red glow plug and forced into a combustion chamber by compressed air. If you put petrol into one of these units which is meant for diesel oil, the auto-ignition wont occur because it is feeding in air at a diesel-air mixture rate, but take away the compressed air by stopping the fan, and auto-ignition occurs. Same principle applies to lpg gas.

Dangers in a diesel engine is that petrol may burn at a higher temperature, or it may not burn at all in the power stroke and possibly backfire in the exhaust system as the air/fuel mixture becomes ideal! Other possibility is the fuel pump not getting lubrication, but if these arent piston pumps, but vane pumps, then I dont think its as bad as its made out to be. I havent disected my high pressure fuel pump, so cant say on its design.

The people I know in Austria use petrol in the height of winter as it helps in stopping Diesel waxing, but there are better compounds for this, only a lot more expensive, so its a tradeoff for them. Ive used Petrol in a 2.8JTD Ducato for 3 years without a hint of problems, but I have had a few problems in my ML, both cars are common rail diesel. I dont think the problems I have are related to the petrol.

 

[Frank Patten]

I was chatting about this to my mechanic on Friday after he had serviced my E220CDI.
He told me that the electric pump in the fuel tank will not be harmed by petrol, only the high pressure pump in the engine bay. To flush petrol out of the system, disconnect the fuel line coming out of the high pressure pump and switch on the ignition. The pump in the tank will pump the contents of the tank out through the high pressure pump (which is not working because you have not started the engine).

When the tank is empty, put a few gallons of diesel in the tank and repeat the process. The entire system has now been pumped through and flushed with diesel, you can reconnect the fuel line out of the high pressure pump, fill the tank with diesel and start up. Check the high pressure connection for leaks!