300TDT fuel capacity???

[Grey Ghost]

Last night I actually RAN OUT of diesel while on the highway (fortunately, I was in the right lane preparing to pull into a rest stop so was able to coast directly to a diesel pump). I had been monitoring my mileage and felt I had at least another 30 miles worth of #2 juice

To my surprise, from dead empty the tank took only 17 gallons! The manual tells me that fuel capacity is 18.5 gallons, with a 2.9 gallon reserve (presumably the amount remaining when the low fuel indicator light kicks on). At my present highway mpg, 2.9 gallons will get me almost 75 miles. I had traveled only 45 of those since the low fuel indicator appeared.

When I look back at the number of times I've filled up with 16+ gallons in the tank, I realize that I'm dam' lucky not to have been stranded somewhere inconvenient.

Can anyone else comment on this discrepancy between the manual specs and REALITY? It seems most un-Teutonic for MB to make a mistake as important as this...

[Tom Hanson]

70 liters

[Grey Ghost]

Tom, my tank only took 17 gallons! Is it possible that I have 1 1/2 gallons of SLUDGE in my tank??

[Al Cooper]

Tom, Is the fuel pick up line to the engine right on the bottom of the tank or up maybe 1/2" or so. I would think it is off the bottom somewhat to keep the 1 1/2gal of sludge from getting in the system

Al in MA:confused: :cool: ;) :D :)

[Tom Hanson]

The fuel line comes of the leading edge of the tank, and not from the bottom as on sedans and coupes. Maybe you aren't getting the full capacity of the tank available. I would think it is easily possible to have sludge in the bottom. You do have a screen in the bottom of the tank that is removable from the outside. Looks like a big nut from underneath. You might pull it outnest time you're close to empty and see what comes out besides clean diesel fuel.

[Grey Ghost]

thanks, Tom. I'll check that next time I'm close to MT

what is the name of your outfit? I'd rather order parts from you than the partsbin.com people...

[VLayton]

Skip,

I bought a 1985 300tdt that had been on a lot for quite a while (a year or so) I've heard of diesel sludge/algae. I've had it 2 1/2 years. Early in ownership it ran out to my surprsie, and after 2 starting gallons and priming, I drove about 5 miles for fuel and she only took a little over 13 gallons. When using the car, and fuel got low, the car would struggle, and perform badly. It made me nervous, but would barely ever take 14 gallons. It was worse up hill, and would clean up once over a crest. I've put 60,000 plus on this car in 32 months, with regular usage of various additives, and now can squeeze over 16 gallons when I push it, which indiacates to me I've been slowly cleaning the system naturally. This car warns me. Any sedan I've run out in there is no warning: you're driving along and suddenly, but not as suddenly as hitting a tree of course, you're not driving along any more. The wagon I mentioned has restarted after dying, very unusual. This isn't alway the case, however, another wagon once ran out 40 feet after refueling! I guess I'd just pulled air in the line at shut down at the pump.

I've run various cars out of fuel way too many times, but fourtunatley more often than not I've made it to a pump, it's quite an ambivolent feeling.

Cheers,

Vince

[Grey Ghost]

that could be used to dissolve the sludge?

I don't know what I'd do with 1 1/2 gallons of sludge once I collected it...

[Palangi]

Power Service Diesel 911 will disolve the sludge, but will clog the prefilter every few hundred miles for quite a long time afterwards.

[Tom Hanson]

Skip,
I'm at Caliber Motors in Anaheim CA. Not far from Disneyland (and I hang out there quite a bit. The wife works there). We have a full page ad in the Star. You can reach me there weekdays at 800 252-6877 ext 306 or hanson_anaheim@mbretailer.com . I hope to hear from you sometime.

[D.L. SWINFORD]

Tom;
In looking at the pre filter vs the main filter; Which is best?
Replies were made that when using a fuel additive to rid the tank of sludge that the pre filter would stop up frequently.
What would happen if you would not use a prefilter and let the main filter collect the goop?
Bad news?
A passing thought; not a suggestion!
Happy Trails Beep Beep from The Spiderman on The Gulf Coast, Don:p :p :p

[docphiliowa]

I have a similar experience with my 240D. I ran the fuel tank near empty so I could drain the tank and replace the first fuel hose. Using my 27mpg and stated 17 gallon tank capacity, I expected 3 or 4 gallons to be in the tank.

Imagine my surprise when only 1 gallon drained out when I removed the fuel tank drain plug.

The book talks about a 2 gallon reserve...where is this reserve?

Happy Spines Beep-Beep from a Chiro in the Midwest
Dr. Phil

[Tom Hanson]

If the tank has too much crud in it, remove it and get it boiled out at a radiator shop. Replace the screen in the bottom and change both primary and pre fuel filters. Should clear up any problems and not such a huge task.

[Jim Grillot]

Pull the plug in the bottom of the tank and see what comes out.

When you refill, put in a shock treatment (1 oz) of Power Service Diesel Kleen. Pre-dilute the Diesel Kleen.

By the way, I have tried to purchase a new drain plug/filter- screen assembly (goes in bottom of tank) three times. Once from our esteemed national technical director and twice from dealerships. Each time the wrong part was in the box. Specifically, the drain plug for a D instead of a TD. Comments, Tom Hanson?

[zak]

Keep the tank at least 1/4 filled. You guys are like my wife !

[Grey Ghost]

Ron at the garage drained the last of my fuel out (about 1.5 gal) and pronounced the tank clean (no sludge). He told me that the position of the fuel pickup makes it possible to run out of fuel when there is almost a gallon remaining (as Tom H suggested in his earlier post).

So, let's all take Zak's advice and buy fuel sooner than the low fuel light comes on!

[D.L. SWINFORD]

G.G.;
I've been watching your request for your fuel tank's capacity.
Per The Technical Data Passenger Cars Book, 1985 for various models, including your 300d.
On page #90 group 00- Filling Capacities, Fuel Tank,
Total 80 liters (17.59 USgal)
Reserve 11.5 liters.(2.52 USgal)
I don't believe this means a total of both.
My experience has been when filling after the reserve light is on; is less than 17.5 gals.
If you don't have this data book it can be obtained from MBNA.
Publication MBNA/MBC 2364.
It is the most valuable book about my Donka II I have.
Happy Trails Beep Beep from The Spiderman on the Gulf Coast, Don:p :p :p

[Grey Ghost]

Zak, you're right about waiting to fill up. In a perfect world, I'd fill up at 1/4 every time. BUT, being the cheapskate that I am, I try to "stretch" that tank out to get closer to a filling station with (relatively) low price per gallon. I paid $2.349 off I-95 this morning, which is $0.17 cheaper than filling up in the middle of Greenwich.

[D.L. SWINFORD]

G.G.;
Owners Manual 300D-TURBO DIESEL.
Inside back cover, quote "Fuel Tank capacity approx. 80l/21.1 US gal, this includes approx. 10.5l/2.8 US gal reserve."
Try these numbers.
Happy Trails Beep Beep from The Spiderman on the Gulf Coast, Don:p :p :p

[Grey Ghost]

Even it's a bit macabre to re-open this thread when Don "Spiderman" Swinford was the last poster, the fuel-tank-capacity issue continues to vex me.

Since June 2004, I have re-filled the Ghost 215 times, an average of 14 gallons per filling. Invariably I wait until the 'low-fuel' indicator illuminates prior to filling. My experience implies a tank capacity of < 17 gallons.

Owner's manual specs cite 80L=21.14 gallons as total capacity, including 10.5L/2.8g of 'reserve.'

That's a FOUR gallon difference...how can it be explained? Tank has no sludge, lines aren't reversed, and the tank is of normal dimensions.

Does the gauge sender fail over time, generating a "late" signal?

[Maxbumpo]

Skip,

My April 1985 edition of Technical Data for Passenger cars says, for all 123 wagons, fuel tank capacity is 70 liters total with 11 liter reserve; this equates to ~18.5 US gallons with ~2.9 gallon reserve. According to this book, your low fuel light should come on when there is about 16.6 gallons left.

So, either your tank has reduced capacity or your sender is incorrect. Any record of the sender being replaced or worked on? I wonder if your tank could be partially collapsed?

[musides]

I've had similar issues. I've filled up Xena 17 times. On average, I put in 16.6 gallons, I get 25.9 MPG, and my fuel warning light comes on at around the 15 gallon marker (e.g. around 415 miles: if I filled up then, it would only hold 15 gallons). What has made my experience a little different from yours is that I have put in 17, 17.3, 17.9, and 19.2 gallons. I have, however, never run out of fuel, and that is about as definitive as one can be.

My book also puts the fuel tank at 21 gallons. It is interesting. When I went 19.2 gallons, I was getting low mileage (about 22) because I was mostly doing 75/80 (Tucson to Phoenix). The low light indicator was on for about 90 miles. With all I've read, I wouldn't doubt that I was a second away from going dry, even though I should have had 2 more gallons.

[Grey Ghost]

So, either your tank has reduced capacity or your sender is incorrect. Any record of the sender being replaced or worked on? I wonder if your tank could be partially collapsed?Meade, my technician swears the tank is NOT collapsed. How could the sender fail? Does it have moving parts?

[Maxbumpo]

The sender has a float that moves up/down with fuel level, riding on two resistance wires. The variation in resistance is sensed and reflected by the movement of the needle in the fuel gauge. There is a set of contacts on the bottom of the sender and bottom of float, so that when it bottoms out, the circuit is completed and the low fuel light comes on.

So, I'm wondering if it would be worth the hassle for you to pull the sender, see if you can find a part number on it, and verify that you have the correct sender.

Did your mechanic drop the tank to make sure that it hasn't collapsed on the top (which would be hidden from view as long as the tank is in place)?

[Grey Ghost]

Did your mechanic drop the tank to make sure that it hasn't collapsed on the top (which would be hidden from view as long as the tank is in place)?I don't believe he dropped the tank; I will ask.

Given your description of sender operation, it would seem that there would be no way for it to register a 'false' positive signal, so I'm back to head-scratching.

What is the approximate cost of a replacement tank, and is the sender unit integral?

[dropnosky]

It would not be unusual for your sender to become inaccurate over time. As the float moves up and down, there is friction in the sender tube with the resistance strip. These can get worn, or gummed up or whatever. On my car, the sender is completely inaccurate after half a tank. Sometimes if the car spent a while parked with fuel in it, the line of the fuel where algae could grow could become inaccurate on the sender.

Take for example the sometimes seen accurate gauge, than when it gets to a certain point it jumps around, or goes to full or empty and generally acts crazy, then gets accurate again.

There is an awesome product I have on my other tank which was sold by the Tempo corporation (gone out of business now, but the product is still out there). It is a mechanical gear fuel gauge. Instead of ohm reading immersed in fuel, the float arm is connected to a gear which turns another gear, which in turn is attached to a magnet on the top of the sender. A second piece of the sender is a sight gauge with another magnet that screws to the outside of the sender. When the one magnet turns, it turns the one outside the tank completely in the sight gauge. That way your ohm readings and float arm are completely separate and there is no risk of any kind of contamination. Then your wires attach outside.