1970 280SL fuel capacity dilemma

[mmizesko]

OK guys,

I never let my fuel get down below R. but close to it, before filling.  when i do, it only takes about 14 gallons US.  then the gauge goes up to above F, and if i keep at it, the expansion tank and the whole car stinks like gas.  I just read again that the tank capacity is 82 L or 21.5 us Gallons. 

So is there really 7 gallons left in the tank below the R on the gauge?  Someone has got to know.  Help? Please?

Mike

[Kevkeller]

Very doubtful. You can always open up the plug and drain it or the access plate on the top to look inside the tank.

[mmizesko]

good advice.  Maybe I'll just drive the 5 miles to Joe Alexander's place.

Mike

[Lori]

Per my owners manual the light means 22-25 miles left which I believe would be about 1 gallon.

[yves]

I have recently emptied the tank to know excatly when the fuel reserve light light up because i have never seen it switched on as i refuel before the needle is too low. Also my gauge stay high after filling but goes down quickly after 2/3 or 1/2 .
What I saw is that the reserve light is on when  i have less than 5 liters .
Under is my scale when i have fulfilled my tank :

[Peter van Es]

Yves, I frequently fill mine to 65 liter of fuel (17.2 gallon) or on occasion 70 liters (18.5 gallon). Don't you ever get that high?

I never let my fuel get down below R. but close to it, before filling.  when i do, it only takes about 14 gallons US.  then the gauge goes up to above F, and if i keep at it, the expansion tank and the whole car stinks like gas.  I just read again that the tank capacity is 82 L or 21.5 us Gallons. 

Is the cork seal at the fuel sender unit intact or is it seeping with petrol?
Do you have a big dent in your tank?

[yves]

Peter  , the 40 lit level is not full , it is what I had in the tank when I have tested the reserve.

[lreppond]

I have noticed that my fuel gauge needle can be somewhat erratic (jumpy) depending on the road surface.  On a rough road, the needle can make huge swings.  On an incline or downhill, the gauge will always read differently.  I’ve pretty much just written off the fuel gauge as a poorly functioning system.  Im wondering if others have experienced the same.  As to the accuracy of the readings, I have lost all faith in mine.  I routinely do a fill up when the gauge reads 1/2 even though I have no idea how much gas is actually in the tank. 

[BobH]

Hello, my needle is pretty stable, but the slightest incline can move the needle significantly.  i guess the condition/resistance of the wiring and the sender unit can all play a part.  The only time i'm confident that the gauge is accurate is after i've filled the tank up, after that it's like Russian roulette!  I just get into the habit of filling it regularly and ignore the gauge, and the clock for that matter!

[zak]

My fuel gauge acts erratically when I first start and drive the car. It reads lower than it should.
But in 5 mins it seems to correct itself. It bounces around a good bit too. I also pretty much ignore it and fill up at a quarter tank.
...just one of those endearing aspects of owning a 60 year old classic car I guess.   

Mike M, hope you find the source of the gas odors.

jz