Decided it was time to change the fuel filters on both of my E300TD's. Read some posts about how to do it before I jumped in. Everyone made it sound easy, no problem.

Went ahead and changed both of the filters(can & screen), was a pretty easy. Filled the filter full of clean diesel prior to putting back on. So far so good. Cranked up after quite a few tries, but finally got going. Let idle for a while, all seemed well. Shut car off, and went and did the other one. Same thing, all appeared good so far. Went ahead after all was said and done, and decided to go for a drive in one of the cars. Got about 3000ft, and died. Damn.

Checked the filter, no fuel in the filter. Filled filter back up with fuel, cranked for a long while, got going again, drove back to house. Decided I was going to let run for a long while this time before I went anywhere. Turns out both cars will run until the fuel filter runs out of fuel, then the car dies. If you refill the filter, car will start and run again, until it runs out of fuel in the filter, then it dies. Did this about 15 times now, same results every time.

WTF is all I have to say. Both cars ran sweet prior to this filter change. Kind of kicking myself now for changing, but figured it could not hurt, yea right. Now have 2 dead cars, neither will run for more than about 3 minutes. Thought that maybe there is some kind of air buble in the fuel intake line, but can not find it. Even tried sticking air compressor hose in the fuel tank, and adding air pressure to push fuel towards filter, but that does not seem to help much. I am at a complete loss here.

Someone with some idea's please help.

Thanks,

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1982 Mercedes-Benz 300CD
1982 Mercedes-Benz 240D - stick

Been there! Try not to get too pissed off, your first fuel filter change on these engines is sort of a 'right of passage' test. Here's the 3 things to remember:

1. A new pre-filter does not come with the O-ring - it is sold separately. Don't ask me why, but without installing a new O-ring perfectly will be a large vacuum leak source.

2. In order to change the pre-filter, you will have to disturb the short fuel line from the heater to the top of the prefilter. If this line looks a little brownish, replace the whole line not just the O-rings. Trust me!

3. Fill the new spin-on filter right to the top with diesel fuel. It will save a recharge on your battery. Even with some air bubbles making their way into your fuel system, a fully topped-off spin-on filter should give you a few minutes of idling time until it starves - just enough time to look for air bubbles in the lines.

I'd also recommend replacing the fuel shut-off valve O-ring while your at it. You don't have to remove the intake manifold for this - just unbolt the windshield washer fluid bottle and push it out of the way.

If the other fuel lines look a little brown as well, go ahead and replace those too (should be less than $100). All the lines except the return back to the fuel tank can be replaced without removing the intake manifold - just unbolt the filter manifold and you should have enough room to get to the rest. The return line can probably be skipped anyway until the next fuel line replacement.

__________________
Scott C.

2006 E320 CDI (120k miles)
FOR SALE: 1998 E300 Turbo Diesel - Black w/Tan Leather - Euro delivery (236k miles)

scott,

Thanks for the wisdom. I am not sure I fully understand, so I will ask some more questions.

1. Both cars only have less than 50K, so all the fuel lines are clear, can see the fuel and air bubles traveling through the lines.
2. The only O-Ring I see is where the fuel line sits on top of the pre-filter. While I do not have a new O-Ring, I am not certain, but the seal at this point seems good, I can hardly pull the hose out of the top once it is seated into the pre-filter. It appears to be very tight, though I will try to procure a new O-Ring, at this point will try anything, can not hurt.
3. I have also tried cracking open the front 3 injectors since these are faily painless to get to. Got the car running, and left injector off until fuel was pumping out like it should, then tightened back up. This usually works to blead air out of my big tractors and other diesel trucks, but has not seemed to help in this case.
4. I have never touched the fuel shut off valve or hose, so not sure about that, but will check it out.

If you think of anything else, please advise, definatly appreciate any help.

Thanks,

scott,

You are so the man. Bigger than sheet, there was a missing gasket/o-ring on the inside of that pre-filter. I had to go dig the old ones out of the trash to figure it out, but there is an o-ring, that I would have never found in a million years, missing. Took the old ones off the old pre-filters, and put them on, started right up, and have been runing smoothly for a while now. Will let them run for about 30 min to make sure, but all the lines are solid with fuel and no air bubbles.

Damn the simplest things always get the best of me sometimes. Would have never guess that the new prefilters did not come with these o-rings. Will go buy some tomorrow, to replace the old ones that I used.

Thanks for all your help and wisdom.

Scott was right on with his advice....anytime you see ANY air coursing thru ANY line backtrack and check the seals of whatever you were messing with.

We've ALL been there and done that with these cars.

If you encounter a difficult seal, lubeing the o-ring with a small amount of silicone grease can help.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Now, if you want to be sure that all is well, clean the entire area off with brake cleaner to make sure you don't get a false positive. Check after a few days. You are reusing an O-ring and you never know what can happen. When we had a leak around the fuel shutoff valve, it was because they replaced the valve and reused the old o-ring. The valve was shiny but the o-ring already had a form. It started but the starting was hard because of the air and it leaked.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Been there too! Glad I could help.

__________________
Scott C.

2006 E320 CDI (120k miles)
FOR SALE: 1998 E300 Turbo Diesel - Black w/Tan Leather - Euro delivery (236k miles)