SushDawg

What would happen if gasoline is accidently pumped into 06CDI.

Family member in a emergency pumped about 1/4 tank of gasoline into a tank that had about 3 gallons of diesel in it. Instead of pushing the car to a location to have it towed, he started it and drove about 100 ft. Car is sitting at the dealership at this point after having it towed.

So question is
1. What kind of damage is he looking at.
2. What does he need to have done to avoid any issue.
3. Does this void the warranty
4. Is this a big repair?

Vik888

This is what they tell people with general aviation piston aircraft .. you can always put higher octane, but NEVER lower. Now this applies to non-diesel engines. No idea if that theory works on diesels.

Your story is slightly incomplete .. what happened after he put gasoline in it? Did anything actually happen or was it taken to the dealership as a precaution?

If you've admitted putting gasoline in a diesel, MB has noted it on record and I would consider the warranty on the engine void. The warranty on the other items like suspension, electronics might not be.

vettdvr

He might be lucky and the fuel didn't reach the engine yet. Destruction of the pistons/rings/rods/cylinders and cylinder heads is very possible.

NEVER start the diesel with gasoline. If you have gasoline in the tank pull the tank drain and flush all the lines.

Otherwise this is Not a big problem just buy a new "crate" engine from Mercedes and flush all the lines.


So this is really important,, DON'T START IT!

SushDawg

He had to take his wife to the hospital and in the mad rush put the wrong fuel in.

Well he moved the car 100ft - nothing happened. Just pulled to the parking lot adjacent to the gas station to call a tow truck. Dealer will be looking at it this morning.

I think gasoline of any octane could be bad. Reading on the internet that since diesel combusts at very high compression and gasoline lower, could be several issues. Others state that gasoline will leave the engine and could ignite in the exhaust system.

Trying to get the real story of what lies ahead and fixes that may done so the dealer does not try and fool him into a big fix.

SushDawg

Whats a crate engine? Too late started and drove 100 ft

Barry45RPM

A Crate engine is a whole new engine in a crate or on a pallet, ready to install with only a few minor components (interconnecting hoses, wires & misc. connecting fittings or "plumbing") that have to be reused from the engine in the car or bought new. In other words, the installer is not assembling the engine from several major subassemblies of "top" & "bottom" before installing the assembled engine.

emilner

Diesel engines ignite their fuel mixture by compression not spark (glow plugs are only used for startup). The significantly higher compression ratio of a diesel engine would probably result in very early detonation of the gas mixture causing severe knocking and or complete engine failure. If gas is ever added to a diesel tank adding oil to the gas would lower the octane rating to allow the gas to burn correctly.

With absolute certainty the engine warranty will be voided...

Clinton Horn

You are getting a lot of alarmist reaction here. Your relative is certainly not the first person to make this mistake. The amount of fuel in the line and filter is PROBABLY more than enough to start and run the motor 100 feet. Diesel will remain on the bottom as it is lower in the petroleum cracking order and I believe it has a higher specific gravity.The gas would rise to the top of the tank and away from the pump. My bet is the car is fine and just needs the tank drained. If the dealer declares an engine swap is in order, chances are he would sell or use it "as is "in a repower situation. Gasoline can cause a diesel to over rev out of control.This does not sound like the situation. Diesels can take ether in small doses and it is much tougher than gas for them to digest.

rjm

An acquaintance of my son did exactly the same thing about a year ago. He was in a hurry and on his cellphone and put gasoline into his MB diesel. He started the car and drove into the street when it died. He had to have it towed to the MB dealership. I think it cost him a couple of days and several hundred dollars to have it flushed out and repaired. It did not require replacing the engine, but it was a pretty involved repair. Apparently it is possible to put gasoline into a diesel fuel tank neck, but not diesel into a gasoline neck.

Diesel Benz

The new diesels have a small diameter tank neck. I guess this is because it would not accept high sulphur diesel, not sure, it's been quite some time like that (here at least). The small diesel pistol would go to the gasser neck, at least the one we have.

jimbo1mcm

No problem. Just fill it up all the way with diesel, and run it. There won't be any problems. The Benz dealer will charge an arm and a leg do stuff that is not necessary. When the tank is halfway down, refill it again with diesel.

blackE500

With that little amount of gas, just fill the tank all the way up with diesel and it will be OK. I have driven MBZ diesels for years and that does happen. You CAN cut diesel with no more that 1/4 tank of dgas in an emergency.

If it was a full tank I would then drain the tank, purge the lines and change the filters. thats it!

vettdvr

This was my first point.. Given it was only driven a short distance I don't think the gasoline made it to the engine and you are probably ok after you drain/flush the lines.

SushDawg

Thanks guys for all your input.

Does not sound like he will be in that much trouble with the car. Just hope the dealer does not do any un-warranted fixes and charge him unnecessarily or the warranty is not impacted.

Will let you know what I find out tomorrow.

csumt76

This happens all the time. They will have to drain the tank, and replace all the fuel filters. It takes some patience to try and get the gasoline out of the fuel rail/pump/injectors.

SushDawg

csumt76 - You will know.

1. Does this impact the warranty.
2. How will the shop determine if the gasoline got that far.
3. Could the repair stop at the filter else the pump as the furtherest point
4. Time required.
5. Approx Cost.

Thanks !!

Diesel Benz

If it had been a W123, I might have just filled up with diesel and drive, but this was a modern CDI, the flush, as csumt76 explained, is a precaution in place.

emilner

Within a few seconds the diesel will have reached the engine. In a fuel injected car the fuel pump builds up more pressure than is needed, the extra fuel is bled back to the tank in the return line. It is one constantly moving loop.

You mentioned that the car was stopped and towed, did it die on it own, or was it just riding rough?

Hopefully if it did die, you will have to only go for a fuel system flush and maybe some fuel system component replacement. After it has been repaired at the dealer (it will be at the owners expense) the warranty should be restored on the engine.

Diesel Benz

Yes but remember, this is a CDI, the major fuel loop is on the low pressure side. What is important is what the high pressure pump feeds to the rail and how much gas enters the rail. My guess is that one could drive a few miles with the amount of diesel fuel in the common rail. Then of course you would not want to spend it all because soon the high pressure pump would start feeding gas. The gas to diesel mixture should be perfectly OK for a mile or so still.

csumt76

1. No
2. Does it run like **** or not start?
4. Depends really on who is doing/how much gas is in there/if it is at the injectors
5. I would say filters, fresh fuel, 3-6 hours labor...

SushDawg

He realized the mistake, but panicked and drove ~100ft to the parking area of the gas station. Did not die. He then called the tow truck.


Runs fine - he just pulled to the parking area and stopped.

emilner

Then he should be ok with a tank flush and maybe a filter/ fuel system cleaning...

SushDawg

Dealer is just going to do a flush and replace the filter. This won't impact the warranty too. Guess he got saved.

Thank you for all your input.

Regards,
TS

csumt76

I have yet to see warranty deny anything... unless maybe you still had the nitrous kit installed in the car and the pistons were sitting in the underpanels.

Diesel Benz

Do you mean that even chip tuning should not avoid warranty? Odd if an engine failure from wrong fuel would be covered by warranty, it the failure can happen in the first place. Can you clarify?