I'm headed out on a decent road trip to Illinois this weekend with the family. We'll be taking my wife's 95 E300 which has always been good to us on long trips.

However, I'm still bugged that it still has a considerable vacuum when we run it low and try to fill the tank. I've looked on the forum and cannot find the tank vent. I've seen a picture or two from the parts catalog, but I can't find this thing under the car to save my life.


Has anyone actually seen the mystical fuel tank vent on a 95 E300 and what did you do to it?

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Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

The tank vent is a little cone shaped thing attached to the bottom of the fuel tank. I jack my car up, put it on jack stands, put boards under the tires (safety first) and use my creeper to get to it. I replaced it a long time ago when I thought it was not working. I tested it after removal and it was fine. Turns out the woosh of air that I was hearing when I uncapped the fuel tank was air coming out. Never did figure it out. Oh well. That was like 175,000 miles ago.

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

I wouldn't necessarily let this go, on my old 300SD it actually started to collapse the tank and the engine was starving for fuel on a road trip up to NH. The vent allows the tank to equalize with atmospheric pressure. On my 300sd, I had a heck of a time getting it to work right. I read some posts where it was recommended to take an air compressor and shoot air up it to blow it out, but mine was so clogged that didn't work for me. I tried running weedwacker line up out after I pulled off the little bell shaped thing near the fuel tank, but that didn't work for me either. Finally, I ended up pulling the trunk back panel off, found the vent line, cut it with a brake line cutter, and made a new vent line out of brake line (just connecting the old line to the new line with a short rubber hose).

Hopefully yours isn't so bad...my SD was considerably older. Connerm is right that the end of the line is underneath the car. If you back the car up on ramps or jack the car up considerably in the back, you should be able to find a little bell shaped piece. This is the end of the vent line, but the line runs all the way up to the top of the tank...this is how it equalizes pressure. If you follow the line from the bell shaped piece, you will find a valve in-line. This is a two way valve that allows the tank to either pull air in or push it out. Try blowing on it in both directions to see if you can easily move air both ways. You shouldn't have to blow very hard to make it do this...if it is hard to get air through try cleaning it with some brake cleaner or solvent and then test it again. If you have access to an air compressor, you will want to blow air through the line that runs up to the tank (with the gas cap off) as well. This should clear out any obstructions. If you don't have an air compressor, at least connect a short piece of rubber hose to see if you can blow air with your mouth up into the line relatively easy (again, this will only work if the gas cap is off).

If you don't feel like messing with all of this before your trip, you can drill a small hole in your gas cap for a temporary fix. I had to do this to get my SD back from that one roadtrip where the fuel kept starving due to the plugged air vent. When the vent line is free of obstructions, there shouldn't be much vacuum or pressure when you pull the gas cap off after driving.

Here is another thread that has a diagram...it may help you a bit: fuel tank vent?


Hope that helps!

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97 S500 (90,000 miles) - wife's car
87 300D (298,000 miles and a replacement #14 head)
94 Suburban K2500 - need something to haul firewood
83 300SD (343,000 miles) (sold)

Does anyone have a picture or a precise description of where the heck this thing is?

NOTHING CURRENTLY ON THE FORUM HELPS

I don't know how to state that any more emphatically than I have. I've been under the tank at least a dozen times looking for this thing and have yet to find it.

__________________
Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]

If you've been under the car at least a dozen times looking for the tank vent and still can't find it, then it's time to hand the job over to a professional.

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2009 E320 Bluetec 117,000
1995 E300D 306,000 Sold
1996 Ford Taurus LX 130,000 Sold
1985 300TD Still 225,000 Sold
2016 Ford Fusion 24,900

Expect pictures shortly. I peeked under my car to find the vent and found the whole area wet with fuel! I guess it's time for some new hoses.

Sixto
87 300D

get under the car and look above the subframe on the driver side - you will see a fitting with a flat shoe shaped rubber on it, if you take off the rubber cover you will see the cone shaped vent everyone talks about. Its attached to the tank with a 2 inch rubber hose, Dont worry you can take it off without drowning in diesel as the vent is from the top of the tank.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)