I urgently need some advice.

E320CDi

I topped up my tank this evening, putting about 3 Gallons of PETROL on top of about 12 Gallons of Diesel.

Was going off tomorrow on long distance journey.

I drove home from the Gas Station, about 2 miles, and noticed nothing amiss.

I was putting the receipt into my expences file to claim when I luckily noticed it said Petrol.

I presume that I need to have everything drained out and the filters changed ?.

Mike Stone

Do a search, both have been discussed here. From what I remember draining and filter change is okey.

I would think you could just drive it and forget about it...you have about 80 percent diesel and 20 percent petrol. Kind of like burning kerosene...not the worse thing in the world.

I also dont see any need for a filter change..what effect will petrol have on filters that diesel will not???

If you are worried about this, drain half the tank and top up with diesel, then add a gallon of the drained material now and then.

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

I watched a guy put about 10% gas in every tank for years during cold months. I would play it safe though and drain it.

A couple of times we had some of our employees fill diesels with complete gas (during my Amoco days). After they died a mile down the road, we'd drag em back and drain them and refill them. Amazingly, I remember most of them working again.

Don

__________________
DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

It would be fine - just burn it off.

Since it has already been driven anyway - it would be just fine.

Hope all is well.

__________________
... Kerry

126 tailed by a 203, 129 leading the pack.

Phoned the Garage that looks after car this morning.

Their advice - Do not Drive under any circumstances.

Arranged flatbed to take Car to Garage.

Cost Estimate -
Tow-In £100 (AutoClub won't pay as it is a self inflicted injury)
Fuel Lost £70
Drain tank and fit New Filters £80
AND FINALLY
Disposal of the contaminated fuel £125

Total £375 (About $550) For a single moment of inattention.

Apparently the Diesel Fuel Pumps on MB's rely on the Diesel Fuel for lubrication.
A single pass of neat or near Petrol will rip the bearings out and put metal swarf into the piping and probably ruin the injectors.

Very quickly after this the Pump shaft will seize and the results are catistrophic.

Any clever thoughts as to a foolproof method of making sure this cannot happen to MB diesel drivers.

Apparently they do this job about 3 times a week regularly.

A fairly pissed off

Mike Stone

Not biting back at Bill but -

Have actually used the same Garage for 17 years.

Their advice and assistance has saved me a lot of money over this time period and I must say they are entirely transparent about the work they do.

Allow you on the shop floor if you want, as long as you are not a nuisance, to see the work being done.

Always talk you through the work done when you come to collect the car.

AND they always have waiting in a box the old parts to show you, if anything is replaced, even the filters etc. changed when you have a service.

I would consider it inconceivable that they would rip me off.

How many of the dealers that are used by the people on this site are that open about their business practices.

The largest amount, for the environmentally friendly disposal of the fuel, apparently includes a large element of tax.
The government takes it off you when you buy the fuel (About £3 a gallon) and then again if you don't want it.
Is there something wrong here or what.

Mike

Mike, I think your garage is being a little bit too protective! Its a well known truckers trick to put some gas in with diesel to thin it out in the winter. If you are worried about lubricity, put a few bottles of DFC in the tank, then drive and enjoy. Gee, I wonder what these guys think of the Soy and Hemp diesels!

He’s right about the fuel pump, diesel pumps are like that. That’s one of the secrets of diesels, to get oil to high enough pressure (1600 psi) to atomize into 22:1 (about 350 psi) engine near TDC. It does it by compressing a lubricating fluid, and depends on it being lubricating. Water will kill them, gas will probably shorten their life, but given how much they cost what you paid isn’t much. If it makes it into the engine it could cost far more, water will put holes in your pistons cause it doesn't atomize, and it might even explode. Consider it tuition

I had a theory of just matching viscosity. If you added thin gas you could add an amount of oil to bring the viscosity back up. The same technique could be used when its gets cold and thick, add some gas to thin it. How about a multi-viscosity fuel oil


And I wouldn't mind getting stuck behind a hemp diesel I wonder if they get many tailgaters

I was browsing alt.auto.mercedes this morning and found this..

It appears that if you put even 2 percent of petrol in with the diesel,
£4000 damage is done.

I made the mistake of putting 1.5 litres of petrol in a full tank of diesel.
This, says the dealer, erodes the coating on certain components in the fuel
pump. The erosion causes particles to be emitted from the pump which lodge
in the injectors causing uneven idle, etc.. To rectify the fault the fuel
tank, lines, injectors, filter, etc must be replaced.

It is common in Europe to mix small amounts of petrol with diesel to stop
the latter waxing in cold weather. Why are Mercedes CDI engines so fragile
to this treatment and why is no warning given?

nigel

I dunno about all this. VW used to recommend - in the owners manual - to add gasoline during the winter to prevent gelling. I think they permitted as much as 50% gasoline. I've sold my old 123, but its owners manual recommended adding kerosene during the winter to thin the diesel - up to 30% as I recall. As such, I just don't believe that 20% gasoline is going to do any harm. I might go purchase an additive which claims to enhance lubricity, but that's about it. Of course, my experience applies only to 'old style' diesels with a Bosch injection pump. Mike is driving a common rail diesel, which may be different. Alas, we don't have to worry about receiving those on the left side of the pond...

- Jim

I gave a fellow I know at the Local University a ring to try and make a little more sense out of this.

He asked a colleague, a lecturer in Fluid Dynamics, to give me a ring.

It was explained that what I had basically done was to float a layer of Petrol (2 Gallons) on top of the Diesel(12-13 Gallons) that was already in the tank.

Mixing would occur at the boundary layer between the two fluids.
If I had acted quickly, without moving the car, I could have, theoretically, pumped the Top Half of the tank contents off by going into through the filler cap. (Repeat theoretically)

As soon as the car started vibrating, through the engine being started, and the car being driven even the short distance to my home it is quite possible that intrusions of neat Petrol would start existing in the Diesel.

Think of it as water globules in oil.

Because the Specific Gravity of Diesel and Petrol are not very different (about 8%) these Globules will soon start to exist at all vertical levels of the tank.

Sooner or later , probably sooner if you allow for Sods (Murphys) Law, the pump will pick up a slug of neat Petrol -- and the rest will be history.


Apparently if you want to mix two liquids with similar, but not the same Specific Gravity, start with the item with the lowest SG and flood the higher SG liquid on top.
(Petrol first then the Diesel)

Even this is not foolproof as the colder it is the more problematical mixing becomes.

He certainly thinks I made the best decision to flush the lot.

Mike

Petrol is completely and rapidly miscible in diesel fuel...both consisting of a mixture of complex petroleum hydrocarbons of varying molecular weights. Diesel contains predominantly larger molecular weight compounds (longer carbon chains) and petrol contains smaller mol. wt. compounds, with some overlap...e.g. some of the longer chains found in petrol will also be found in diesel. Petrol has a higher volatility and thus lower flash point than diesel, but both substances are similar in that they are comprised of petroleum hydrocarbons.

The phenomenon of a "boundary layer" is used with reference to two liquids that are not miscible, such as diesel fuel and water. But this does not apply to diesel and petrol...you will not have globules of petrol floating around in diesel, e.g. you will not form an "emulsion"....a few gallons of petrol in a diesel tank will be completely mixed in very short time.

I also just dont buy the dealer recommendation to pump out the tank as such an expense.

If the lack of lubricity in gasoline was a concern, you could have just added a quart of straight 30 weight non detergent oil and run the car.

The discussion pertaining to the difference in specific gravity is not relevant here...yes the spec. grav. or even the difference in temperature between the two liquids will have a minor (theoretical) influence on how the pure products will tend to position themselves (e.g. which will tend to float above the other). However, with two liquids that are COMPLETELY miscible, such as diesel and petrol, the overriding factor is misciblity.....these liquids will very quickly dissolve into each other, forming a resulting mixture of petroleum hydrocarbons, containing a greater proportion of higher volatile, lower molecular weight, hydrocarbons than regular diesel fuel, but in the end, not so radically different from diesel fuel as to warrant pumping out at great expense. There simply will not be any globules of petrol floating around in the diesel fuel waiting to be picked up by the injection pump which will then suffer great harm....wont happen.

I'm not convinced, but then again, I'm not an engineer with Mercedes Benz, and I know absolutely nothing about the injection pumps on the CDI cars.


Mike, your E320CDi is a real sweet looking vehicle...the opinions of those of us who like to tinker with our old 123 diesels, which would probably run on shaving lotion, may not apply to the newer higher tech vehicles. I'm glad your car suffered no ill effects.

Mark

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

Shaving lotion sums it all up.
Keep the humour.

I have found that there is an upside to my fairly miserable and expensive day.

I used my old car, a 1983 190E - 96k Miles from new, this evening for the first time in a long while.
My wife took it over from me when I bought the 320CDI.

It still is a bloody GOOD car.
Fairly rapid, good handling, comfortable and not a million miles different from my new technoligical marvel.

I nearly sold it for £1400 a while back.
I must have been having another bad day to even consider it.
I was 39 when I bought it.
I have realised it is part of the family after all this time.

OK the steering wheel is large and it does not have a 6 speaker stereo with autochange CD.
Neither does it look like the bridge of the StarShip Enterprise when I turn the ignition key.

There is in fact a part of me that says "Why did you spend all that money on something that is not fundamentally better".

MB deserves a medal for the 190 Series.

I wonder if my technical miracle that is full of computers, air bags, digital information buses and gizmos will still be in as good condition as the 190E in 16 years time.

Mike