I had the diesel fuel injector resealed three months ago, since it was leaking oil. Also new injectors and new fuel lines at the same time. Found a fuel leak 3days ago (smell, dripping in parking lot). Took it to same mechanic, who could not find exact cause. He removed "diaper" (protective cover under engine which was wet from leak), wiped and sprayed, ran motor on lift, no obvious leak. So he said to take it home and put papers on garage floor, etc. It did not leak on the way home (7 miles), and did not leak over night. So I took it out and drove about 2 miles, brought it back into my garage and it started dripping fuel onto papers on garage floor. Any ideas why a leak would stop temporarily, then start again?

Are you positive it is diesel leaking and not coolant? I had a leak a few months ago I assumed was diesel (didn't look close enough) - turned out to be my radiator. It would stop leaking as it would heat up, and when it cooled - it would start again...

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1995 E300D - 225,000 miles - White Exterior, Grey Interior - original owner

Not sure what you mean about resealing "the fuel injector" as your engine has 6 of them, but anyway, there are a ton of places for fuel to leak, mostly having to do with the plastic fuel lines on the 606. But you say you had them replaced recently, so that's odd. It could still be a bad or out of place O ring on a fuel line, I suppose. I think visual is the best way to find the leak - if, as you say, it is leaking sufficiently that you can actually see it dripping on the floor, that is definitely a significant leak that you should be able to see happening. Prefilter O ring is an easy replacement, as is the main fuel filter itself (with associated O ring). Fuel line replacement is more involved as you have to take off the intake manifold.

Just my opinion.

Rgds,
Chris W.
'95 E300D, 214K

Sorry, I meant to say "injection pump". I had it resealed due to oil leak, and also replaced the six injectors and fuel lines.

Turns out it needed 6 rubber "O" rings and 6 copper seals at fuel injection pump. Car has 110,000 miles on it.

I had a leak spring up on my '95 also. I ended up replacing the fuel lines and have not had any problem since. My leak was the banjo fitting on the back of the IP. The rest you can replace without pulling the intake, not that one.
The lines were about $120 and I got the O rings for the intake and the manifold gasket also. I think my total was less than $150 and it took a good afternoon to do, but it should last at least another 100 thousand miles. Mine would leak after driving to work but not when I got home.
It is worth the trouble.

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Habits I support
95 E300 D 220,000 & counting (I think I'll call him Fritz)
02 Tahoe (Momma's ride)
98 GMC Sierra 120,000
57 Chevy Nomad (bought in '69)

My 95 starting leaking a couple weeks ago. Dealer replaced all the lines and rings... cost about $400 total

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1995 E300D - 225,000 miles - White Exterior, Grey Interior - original owner