Hey, everybody, I have a question about my wife's 300 D reserve light. The manual says it should come on when it's down to about 3 gallons, but the light regularly comes on when it's between the 1/4 and 1/2 marks, then doesn't normally budge from there until we fuel it up. The other day I had driven about 30 miles on it, without it moving any, put 2 gallons of fuel in it just to see what it would do. It then went down to just above empty, for the first time that I can remember, (even though I usually fill it up when it's at this point). Is this the normal thing for an 81 300, or does mine have a glitch that I need to get fixed. If so, what is the fix? Thanks for any help in this matter. Lee

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"Knowing is not enough, we must apply.
Willing is not enough, we must do." Goethe

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1951 Chevy 3100

2003 Indian Chief Roadmaster

1983 GMC 1 ton Dually

1982 Chevy 1 ton Dually, service body (sold)

'90 GMC Suburban 6.2 "SS Veg-Burban"
(single tank WVO\diesel conversion) SOLD

'81 300D ~ Mama's car...my job (now my car)(but still my job) SOLD

'83 300sd ~ rescue car SOLD

2005 Ford Taurus (Mama's new car)(NOT my job!)

It's sounds like you fuel level sending unit needs a cleaning. You can access it if you remove the First-Aid box on the back window deck. Then there is a nut on the bottom of the sending unit that you remove then you can take the unit apart for cleaning. Be gentle with it because there are three wires inside that you don't want to break. Clean it with some brake cleaner, let is dry and re-install.

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Or try putting some biodiesel in the tank. After about a week of mine behaving much like yours, the bio loosened it up and now it seems to work properly. Good luck.

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1998 E300D, 287k, barely broken in.

Mine comes on somewhere around 1/8 tank which I believe is correct. I agree that you sender is probably sticking.

I experienced the same issue in my 300CD. Fuel light was on even though the needle was above the 1/4 mark. Removed the fuel sender, carefully opened it and found the reason why - see pics.

After carefully cleaning the sender with brake cleaner and re-assembling, it works fine. It took a while to remove all of the gloop, but the float now moves smoothly and the fuel light does not operate prematurely.

In the meantime, the bottom of the fule tank was coated in the same black gloop. So after following Dave Morrison's removal procedure (thanks Dave!), I took it to a radiator shop for cleaning. The shop did a good job of removing the gloop, but this has revealed surface rust in the bottom quarter of the tank. Nothing serious, but I am planning to re-line the tank using a POR-15 tank sealer kit. Will attempt to post pics of the before and after.

Cheers!

Attached Thumbnails

   

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Neil.


1991 190E 2.6 170k
1995 E320CA 57k
1999 Chevy Tahoe 98k
2000 R1150GS 45k
1983 300CD 178k - sold, but not forgotten

Yee-uck! Wow, that's some nasty looking stuff. Thanks for all the help. It wasn't a real major problem, but it seemed really strange for it to kick on right after passing the half tank mark. I really appreciate the info on how to get rid of the problem, too. Thanks for the replies and especially the step by step on what to do. I'd have never figured out where to start by myself. What a great forum! Lee

__________________
"Knowing is not enough, we must apply.
Willing is not enough, we must do." Goethe

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1951 Chevy 3100

2003 Indian Chief Roadmaster

1983 GMC 1 ton Dually

1982 Chevy 1 ton Dually, service body (sold)

'90 GMC Suburban 6.2 "SS Veg-Burban"
(single tank WVO\diesel conversion) SOLD

'81 300D ~ Mama's car...my job (now my car)(but still my job) SOLD

'83 300sd ~ rescue car SOLD

2005 Ford Taurus (Mama's new car)(NOT my job!)

Yup- I have seen a lot of those icky sending units down here in FL . If yours looks this bad you might want to pull the tank and clean it out before you run into trouble with the tank, filters etc.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

how would one go about removing the tank? Isn't there some screen/filter somewhere that needs cleaning too?

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1963 Ford F100 - Cummins Swap?
1985 Mercedes 300SD - 210K
1992 Ford Festiva - 92K
2001 Ninja 250 - 8K

Tank comes out through the trunk. The fuel strainer in the tank is accessable under the car, drivers side, just a bit behind the half axle. Note, drain the tank before pulling the strainer.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Mine, not at all. I learned the hard way.

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1980 300TD-China Blue/Blue MBTex-2nd Owner, 107K (Alt Blau) OBK #15
'06 Chevy Tahoe Z71 (for the wife & 4 kids, current mule) '03 Honda Odyssey (son #1's ride, reluctantly) '99 GMC Suburban (255K+ miles, semi-retired mule) 21' SeaRay Seville (summer escape pod)

Also - be careful when you drain your fuel and keep it from dribbling all over your CVJ axle boot. I ignored this sage advice and guess what?

Several months later I found a tear on top - right under the tank. Awesome.

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1981 240d - 135k - Arlene