'85 300D fuel line help

[sesameeyes]

The sequence of events:

Oil terribly low (almost dry) and an ominous knocking on the way up the mountain

Full oil change, 8 LITERS

Drove normally for a couple trips then loss of power and shutoff. After letting it sit for a bit we limped it a couple miles, loss of power shutoff...this happened about three or four times and the time in between getting shorter. It seemed to help letting it sit for fifteen minutes or so but eventually the battery ran out of juice.

Upon inspection there appears to be oil around all of the injectors and the exhaust manifold.

Prior to this we had run out of diesel probably 2 or 3 times and had to prime the system and pretty consistently run on the minimal amount required (to be young, wild, and poor)

Also.. EGR delete, ignition replaced, the vacuum lines are a bit of a mess hell if I can figure them out and definitely leaky (been having to shut of the car with the emergency shut off under the hood for awhile) and a rat moved in under the steering wheel but there doesn't appear to be any damage to the wiring.

We have been purging the fuel line on and off for awhile now, fuel coming from all the injectors and she will catch every now and then but havent gotten her fully started.


Ordered filters but they only sent the plastic one, waiting on the screw on.

What I am wondering is should I continue in my efforts to purge and prime prior to replacement and what are the chances that I am possibly getting air in somewhere? Copper washers? Maybe some entire other reason she wont fully start...(a friend mentioned the neutral safety switch?) Any encouragement, suggestions, insight, help, general unrelated advice appreciated. Tired of being stranded in these lonely hills.

Will post pics as soon as I get back to the car.

[Diesel911]

Originally Posted by sesameeyes

The sequence of events:

Oil terribly low (almost dry) and an ominous knocking on the way up the mountain

Full oil change, 8 LITERS

Drove normally for a couple trips then loss of power and shutoff. After letting it sit for a bit we limped it a couple miles, loss of power shutoff...this happened about three or four times and the time in between getting shorter. It seemed to help letting it sit for fifteen minutes or so but eventually the battery ran out of juice.

Upon inspection there appears to be oil around all of the injectors and the exhaust manifold.

Prior to this we had run out of diesel probably 2 or 3 times and had to prime the system and pretty consistently run on the minimal amount required (to be young, wild, and poor)

Also.. EGR delete, ignition replaced, the vacuum lines are a bit of a mess hell if I can figure them out and definitely leaky (been having to shut of the car with the emergency shut off under the hood for awhile) and a rat moved in under the steering wheel but there doesn't appear to be any damage to the wiring.

We have been purging the fuel line on and off for awhile now, fuel coming from all the injectors and she will catch every now and then but havent gotten her fully started.


Ordered filters but they only sent the plastic one, waiting on the screw on.

What I am wondering is should I continue in my efforts to purge and prime prior to replacement and what are the chances that I am possibly getting air in somewhere? Copper washers? Maybe some entire other reason she wont fully start...(a friend mentioned the neutral safety switch?) Any encouragement, suggestions, insight, help, general unrelated advice appreciated. Tired of being stranded in these lonely hills.

Will post pics as soon as I get back to the car.

I am not following what happened.

Your oil was low and you had knocking going up mountains. After that you changed the oil and filter. do I have that right so far?

"Drove normally for a couple trips then loss of power and shutoff." Does this mean it lost power and then the engine stopped running by without you shutting it off? And after starting again that situation repeated itself a few times?

When you found the oil everywhere what was the oil level when you checked the dip stick?
If your oil fill cap was not on correct oil could go a lot of places. If your crankcase pressure was too high or your venting tubing was restricted the pressure is going to go somewhere.
The high crankcase pressure can also shut off the engine.

Or the oil could be from a leaking valve cover gasket.

If it happens that your spin-on fuel filter is plugged up no amount of fooling with the system is going to change that.

Air can only get into the system from the old style hand primer with the shiny aluminum body or from the 2 sections of hose and the plastic fuel filter. Because that is the suction side.

Along with young, wild, and poor is impatience. Slow down and think about how things work.

Also there is an old saying. If you own an old Mercedes you are either rich or a mechanic.

Two other areas that can cut your fuel off are a plugged fuel tank screen and if the fuel tank vent to the front of the left side rear wheel area is plugged with mud or what ever.
If you drive with the fuel fill cap off and it runs normally, and you put the cap back on and it runs crappy that is an indication the vent is clogged.

You never mentioned if you could see anything inside of the plastic fuel filter.


Attached picture of a plugged tank screen.

[barry12345]

Did you lose oil pressure? Any oil showing on the dipstick now?

[mytimeyet]

I am reading 2 mostly unrelated issues, loss of oil and poor fuel flow. You will need to get the engine running again by getting the fuel problem 1st so you can track down the oil problem.
Filters are a good 1st step. Line inspection, primer pump, tank screen pretty much in order after that. You should be able to 'check' the primer while swapping the filters. You will be using it the fill the filters and pump out air. If you are seeing foamy bubbles in the clear filter there could be problems upstream at the primer or lines. When checking the lines look carefully at the clips that hold the lines to the body for wetness. (could be fuel or brake fluid!) Check where the lines go over the rear subframe, this is a place where dirt/salt/junk can accumulate and corrode the lines. (been there done that). Also the wetness reported around the injectors could be either oil or fuel from the fuel return lines or both. (Been there too)
Good luck and good hunting