tank screen - fuel remaining - PeachParts Mercedes-Benz Forum

digieditny · #1 04-03-2012, 09:56 AM

1984 300td euro. Just a quick question... How much fuel should I expect to come out of the tank once I run the car to empty? I really need to tackle the tank screen but right now I only have a 5 a five gallon bin to empty the diesel into.

Also, once I do the work, is there anything special I need to do to get the car running again? Fill the tank and prime?

Digi

Phillytwotank · #2 04-03-2012, 10:02 AM

that's going to depend on how dirty or clogged is the tank screen. Also, if you "jack up" the car to gain access to the tank the the increased angle will send some of the fuel to the sides of the tank away from the screen. If you're using a lift and keep the car level then that wont be a issue.

pwogaman · #3 04-03-2012, 10:03 AM

A clogged filter will keep some fuel from working out by gravity, until you start to loosen the filter. Once you get as much out as you can, then tilt the car to one side as much as is safe to do, so what fuel is left will pool off center in the tank. If you are down to that level, five gallons capture capacity should be more than enough.

ah-kay · #4 04-03-2012, 11:36 AM

It depends on how you 'run it to empty'. On the SDL I pumped the fuel out from the feed line until NOTHING came out. I then removed the hose underneath the tank and it dripped ever so slightly so I thought the tank was empty. However, when I loosen the tank screen, a gush of fuel came out because the screen was clogged bad. It leaked into the trunk and what a mess it was. More than a few gallons came out.

So if I do it on another car, I would insert a hose into the tank and try to suck it as empty as possible. You may get luck if the screen is not too clogged.

charmalu · #5 04-03-2012, 11:55 AM

The tank screen is about 3 inches long, so depending how much is clogged up will depend on the amount of fuel to suddenly come gushing out when the screen is removed.

You might be able to remove the fuel return home from under the tank, and drain from that hose. use some 6" needle nose Vice Grips on the hose, remove the hose from the supply pipe, then place bucket under the area and remove the VC. may work, haven`t tried it.

I always thought the return line came in from the top of the tank. looking into a tank I just cleaned with a light, I see it sticks up in the middle of the tank bottom about an inch.

This currently running thread has some good info.
http://www.peachparts.com/shopforum/diesel-discussion/244831-w126-tank-screen-dilemma.html

Charlie

Biodiesel300TD · #6 04-03-2012, 11:58 AM

A really cool trick to avoid spillage that I've used many tims, is to put a shop vac into the filler neck. Make sure it's in there loosely, you don't want to collapse the tank. Turn it on, and then start removing the hose and screen. I've done this with tanks that have several gallons in it and not dropped a drip with the screen completely out. But be warned if the shop vac hose falls out you'll have a huge mess. So keep an assistant attending the hose. Also DO NOT DO THIS ON A GAS TANK, diesel only. The gas fumes can ignite, where as diesel will not.

Orv · #7 04-03-2012, 01:59 PM

On my wagon I just had the new screen ready...yanked the old one out, shoved the new one in, with a drain pan underneath. I only lost about a pint of diesel. Only problem was, the rush of diesel washed a lot of the crud off the strainer, and because of the way the wagon tank is designed a lot of it then ended up in my fuel filter. I don't think this would be a problem with a sedan, that strainer works differently.

The shop vac trick is super cool, I might have to try that next time.

digieditny · #8 04-03-2012, 02:28 PM

Orv. Interesting... How empty was your tank when you did this? When does the fuel start gushing out? Once you removed the tank screen completely or once you started unscrewing? Just want to know specifically what's going to happen so there's no surprises. What about the O-ring?

I never thought about doing it that way but now I'm thinking it might be the best way since I'll be doing this on the street.

ah-kay · #9 04-03-2012, 02:36 PM

I would not 'yank' it out and 'shove' it in. So many things in the way and you are on your back lying down. I would not use the Shop Vac either. You leave too much to chance and possibly another person. Just empty the tank as much as you could, or purge the tank with compress air to dislodge any debris before you try to drain it.

The other thing you can do is to cut the feed hose and shove a switch valve or something ( golf tee ) to plug the hose if necessary and drain it slowly.

Wear protective eye goggle. The last thing you want is diesel all over your face. Good luck.

Biodiesel300TD · #10 04-03-2012, 03:03 PM

It can be a messy adventure any way you go about it in my experience. I've done it when I thought the tank was "empty" after draining it out via the supply hose, but it still had a few gallons in it due to a clogged tank strainer not allowing all the fuel out. I've come out from under the car soaked in diesel, and I've come out with out dripping a drop. The shop vac trick works well, if you don't want to drain the tank, but there is definitely some room for ol' Murphy to drop in.

Yak · #11 04-03-2012, 10:32 PM

Keep in mind, he's got a TD. The screen on the TD does not have the supply line coming out the center, it's more like a stopper.

The wagon tank is different, flatter, with the "inner tank" bottom portion. Check out the other currently running tank threads.

In your situation in Brooklyn, make sure you've got the correct TD-style screen, the proper socket/wrench/tool to remove, and any other gaskets or O-rings necessary.

He's posted before about fuel starvation-like symptoms, so it's possible he's got a fair amount of crud.

Based on Orv's experience with the TD tank is there something else he should do or try first to assess or dissolve the gunk? Maybe pull the gauge sender as an indicator of the muck level? Or pull the sender and use a cheapy siphon pump from above? They're maybe $10 at Walmart.

Brian Carlton · #12 04-04-2012, 12:20 AM

Do yourself a huge favor and follow the procedure established by Kerry:

Disconnect the fuel return line from under the hood and route the line into a five gallon container (using some additional hose).

Start the engine.

Return to the house and have a cup of coffee.

Return to the vehicle (which has now stalled due to the lack of fuel), reconnect the return line, and remove the tank screen. You won't get more than one pint draining down upon your head.

All other advice............worthless.

ah-kay · #13 04-04-2012, 12:38 AM

Quote:

Originally Posted by Brian Carlton

Do yourself a huge favor and follow the procedure established by Kerry:

Disconnect the fuel return line from under the hood and route the line into a five gallon container (using some additional hose).

Start the engine.

Return to the house and have a cup of coffee.

Return to the vehicle (which has now stalled due to the lack of fuel), reconnect the return line, and remove the tank screen. You won't get more than one pint draining down upon your head.

All other advice............worthless.

WRONG. You made a incorrect assumption that the tank filter is not clogged. The tank strainer is about 2 1/2" to 3" high. If the bottom half of it is blocked then you are left with a lot of fuel in the tank though the car stalled. Ask me how I know.

Brian Carlton · #14 04-04-2012, 12:40 AM

Quote:

Originally Posted by ah-kay

WRONG. You made a incorrect assumption that the tank filter is not clogged. The tank strainer is about 2 1/2" to 3" high. If the bottom half of it is blocked then you are left with a lot of fuel in the tank though the car stalled. Ask me how I know.

If the vehicle is moving under it's own power, the procedure works. If it has stalled due to a clogged tank filter, only under that condition would you be correct.

Since no mention was made as to a non-running vehicle, my assumption is deemed to be proper.

ah-kay · #15 04-04-2012, 12:50 AM

What I am saying is that if the lower part of the filter is clogged then there would be fuel in the tank even though the car stalled. It does not matter that the car was or was not running. I am not a mechanic but all my posts are factual and based on my experience. Some are pleasant, some are not. This one was NOT.

It is not rocket science to drain a tank. Just to be careful and wear protective clothing and goggle. Enough said for me.