1995 MBZ E300 Diesel idle

[1995E300D]

Hi all,

I recently picked up a 1995 Mercedes E300 Diesel with 169k miles on it.

Motor mounts were shot, I replaced both engine mounts and transmission mount for good measure.

There was fuel leaking out of the delivery valves, so I bought the socket to replace the delivery seals and crush washers. I made sure to clean the area as best as I could before removing each DV. Installation went reverse of removal. All of them threaded back in easily. One worry of mine was that whatever was below the DV might not center properly or the spring might not seat properly.

Anyways, I also replaced all 5 of the plastic fuel lines with new lines, new fuel filter and o-rings, new pre-filter with new o-ring. I also replaced all the glow plugs while I had intake manifold off, one of them was very stubborn, but I got lucky and it didn't snap off. My wiring harness is in bad shape and will need to be replaced ASAP and the breather vents under the plastic valve cover need to be replaced asap.

I do notice that 2 of the 5 fuel lines, you can see some air bubbles inside. Is that normal? Does the video below of it starting and idling sound normal? The other line you can see air bubbles in is the one that foes on the reverse side of the pump with banjo bolt. I'm wondering if the new pre-filter isn't seating all the way and letting air in.

https://youtu.be/oEInJo5EVwc

Other than that, the power is about the same, probably starts a little better than before changing out the seals.

I just wanted to make sure that this normal for these N/A OM606 diesel engines and if not, what I may need to do to remedy this.

Thanks for any help!

[vstech]

Bubbles are normal after fuel line service, but it should quickly clear up and not return.

[jbach36]

Sounds good.

[1995E300D]

Thanks, I took it for a test drive and about 1 minute into it, I heard some pretty hard hammering, though no loss of power. I was just going around the block so I pretty much coasted into the driveway and back on the ramps.

It appeared that two of the injector lines on the deliver valves were not tightened properly. This made me second guess everything, so off went the intake manifold and disconnected each fuel line from each DV, undid the clips that hold the DV's in place, and one by one, removed each delivery valve to confirm the spring was still where it was supposed to be. Everything appeared OK, but I wanted to be sure. I didn't mind too much as I also wanted to R&R the oil pressure sender, the original one was giving a rating of 3 bar at all times...even with the engine off. Now that reads as it should.

This time, I tightened the DV in three steps and centered it before tightening anything, torque, then back off, torque, then back off, then a final torque. Put everything back together and I don't see any leaks so far. I do still see some bubbles in one line, fairly consistently, how long before this "normally" goes away? All new plastic lines came with their own seals.

The breather ports for either cylinder 2 or 3 aren't seating properly due to brittle age, other than some extra blow-by in the engine compartment, would that give me that much extra noise? I'm hoping to have those parts in soon.

Here's another video I made after the above work:
https://youtu.be/Se1B_jFu-yk

I test drove it and there didn't appear to be any substantial nailing like before. Everything looks fairly dry.

[Chris W.]

After the DV seals were done on my car it had some nailing for a surprising amount of time, many minutes before it slowly declined to normal. At 169K your engine has a great deal of life left in it, so if you like the car, take good care of it!

Rgds,
Chris W.
'95 E300D, 460K