Diesel Fuel Leak!! - PeachParts Mercedes-Benz Forum

jbach36 · #1 07-06-2006, 06:38 PM

I have a '91 300d with 90k on it. Got home, opened the hood to do an oil change, and there's fuel leaking from the upper part of the engine. I tried to trace it up to the source, no exact source found. There are the 5 tubes (copper lines?) going into the engine. They have nuts on them that can be tightened. I sort of doubt those are the problem, and I'll check those for tightness, but if they got loose once, they'll do it again. I can't have fuel on my engine. Any thoughts on the problem?

Thanks,

Jeff

ohiomike · #2 07-06-2006, 06:54 PM

Check on the drivers side back of engine as there is a small hose there which serves as a cap. often it gets old and leaks fuel. Or check at the emergency shut off on side of engine as it might need a new o-ring.

stephenson · #3 07-06-2006, 10:59 PM

I'm still giggling ...

You are doing your oil changes yourself, but can't identify the fuel lines from the injector pump to the injectors?

I salute you!

Perhaps a shop manual is a good idea?

orthotomeo · #4 07-07-2006, 03:17 PM

Those 5 brass looking lines run fuel to your injectors. Your problem is probably the injector return lines. Those are the tiny rubber (or cloth braided) looking hoses that go from injector to injector all the way to the fuel filter. They call it "weeping" and they probably need replacing.

A short term alternative is to clip off the bottom 1/4 to 1/2 inch of each return line (or whichever it is leaking) and reconnect, because that's likely where the leak is coming from (no tight seal).

Dervman · #5 07-07-2006, 05:08 PM

Quote:

Originally Posted by jbach36

I have a '91 300d with 90k on it. Got home, opened the hood to do an oil change, and there's fuel leaking from the upper part of the engine. I tried to trace it up to the source, no exact source found. I can't have fuel on my engine. Any thoughts on the problem?
Thanks,
Jeff

The 603 engine in my '87 SDL has a small continence problem also. The bottom cover gasket on the Injector Pump is leaking slightly so that over a period of a few weeks it will seep out enough fuel to fill the crevice in the LH motor mount and coat the side of the block below the pump. The previous owner said it was like that when he bought it 5 years ago and it doesn't seem to get any worse. I tried tightening the bottom cover bolts but it didn't help much. When I get to having to rebuild the injection pump I'll tackle it then, for now it is so minor I don't worry about it - you can't smell it in the cabin.
One weird thing though, the leak gets worse if the car is left idle for a few weeks then reverts to normal seepage once I start using it again.

stephenson · #6 07-07-2006, 07:14 PM

Dervman,

My IP had bottom plate leak also, but I think it was oil that was leaking instead of fuel ... are you sure that is where the fuel is coming from?

Mine got worse and worse ... finally had it fixed during front end work ... was a real mess - but, no alternative.

jbach36 · #7 07-09-2006, 04:06 AM

I took my '91 300d to a shop, they sold me 5 rubber washers and 5 metal washers. I think it's at the delivery valve area? Not sure of the names of the parts. I used a torx wrench to get the 3 collars off, but need to figure out how to do the rest. The shop said that I do not loosen the large nut above the splined nuts at the base. Not sure how to do this. I've also been warned these things are under a lot of pressure. Do you know how to replace these washers? If I knew how to post pictures, I would, to show you the area. How do you post pics along with messages?

Thanks,

Jeff