Foaming at the pump. - PeachParts Mercedes-Benz Forum

Newguy · #1 12-19-2007, 10:35 AM

I bet you thought that I was going to complain about high diesel prices

Even though diesel is $3.35 / gal in Colorado, that not the subject.

Whenever I fill up my tank, I seem to get a lot of foaming. This causes the tank to appear full, even though it isn't.
A 1/2 day later and I can get several more gallons in.

This isn't that big a deal except two things:
1) I can't easily get a full tank, therefor I have to fill up more often.
2) It makes it really hard to determine my fuel economy.

Does anyone else have this issue? Just curious.

vstech · #2 12-19-2007, 10:38 AM

is this on a trucker pump or a car pump?
trucker pumps REALLY pump out fast, causing more foam.
try filling at 1/4 squeeze on the nozzel. have fun.

Newguy · #3 12-19-2007, 10:45 AM

Thanks, I guess I usually do fill up at a farm station. But I have noticed in town as well.

TX76513 · #4 12-19-2007, 10:56 AM

Velocity will cause diesel to foam but it should quickly disperse. Oil companies treat diesel fuel with organic additives, such as detergents, cetane improvers, viscosity breakers and occasionally perfumes (collectively referred to as "DAP"). Each oil company has its own preferred DAP which it typically uses only for mixing with its own fuel. All of these organic additives must be compatible with the defoamer.

Diesel fuels delivered to filling stations also may contain some amount of dispersed or dissolved water which can adversely affect the performance characteristics of previously known defoamers. The water causes a decay in defoaming characteristics and in some extreme cases, may cause the defoamer to enhance foaming, rather than suppress it. Such wet defoamers also can result in increased sludge deposition in the fuel tank. Standing foam is an indicator of fuel with a moisture content.

#5 12-19-2007, 12:27 PM

I never fill with the nozzle handle beyond the first hold stop (There are usually 3). It takes longer but I don't have to mess with foam.

Newguy · #6 12-19-2007, 12:31 PM

OK, I'm just glad I'm not the only one seeing this.

TX76513 · #7 12-19-2007, 01:17 PM

The SDL can take the big hose and fill 20 gal. in a couple minutes. The SD won't gobble (swallow) as fast maybe postion 2 on a good day.

vstech · #8 12-19-2007, 01:18 PM

hmm, I wonder why the sdl is better with the high flow? they must have changed more than the legroom back there.
My SD handles the high flow fine, but it does have to be burped to top it off.

F18 · #9 12-19-2007, 01:54 PM

I also notice winterized Diesel fuel with the additional additives seems to foam more. I usually have to stop filling and burp the tank on the 98 E300 by putting a little of my body weight into the side of the car and give the vehicle a jiggle.....then I can top off the tank. On my old K-1500 Diesel Blazer I use to jump on the rear bumper to dislodge the trapped air from the foam in the tank to help filling.
Cheers!

turbobenz · #10 12-19-2007, 02:18 PM

yea its annoying. I went to autozone and asked them if they have an antifoaming agent, they asked me "what are you talking about, foam"??

drskipper · #11 12-19-2007, 04:08 PM

Sounds like Rabies

it needs its shots.

TX76513 · #12 12-19-2007, 04:10 PM

Quote:

Originally Posted by vstech

hmm, I wonder why the sdl is better with the high flow? they must have changed more than the legroom back there.
My SD handles the high flow fine, but it does have to be burped to top it off.

The neck sizes are different. The SDL can take the big hose all the way in

The SD can only swallow a couple inches.

LUVMBDiesels · #13 12-19-2007, 04:19 PM

This is what I do for the 300SD...
I pour 3 or 4 ounces of Disel Kleen and 2 ounces of Lucas Fuel treatment into the tank.
Than I fill it until the pump shuts off automatically. It doesn't matter which 'stop' I use on the nozzle, in fact in NY and Pa they remove the auto hold feature on self service pumps. (guess they want us morons to hold the darn thing the whole time)
Once the pump shuts off, I bounce the car and get it rocking. This gets the air out as I slowly fill it. I canusually get three or four burps out of it before fuel not foam comes all the way to the top of the filler pipe. Once I think I am really full, I bounce her again and maybe get one more burp. then I fill it again.

I get it filled all the way that way...

TX76513 · #14 12-19-2007, 04:22 PM

Quote:

Originally Posted by LUVMBDiesels

Once I think I am really full, I bounce her again and maybe get one more burp. then I fill it again.

I get it filled all the way that way...

I do that too, but not at the pumps

toomany MBZ · #15 12-19-2007, 04:33 PM

Yes, I get that sometimes, it won't even trickle in, I fill up across the street. This happens at the same pump I've been using for a year or more. The last two times it happened I spoke with the person inside, and told 'em I'm taking my business elsewhere. Seems the fuel velocity can be adjusted in the pump somewhere. Better now.

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