Leak at injection pump fittings, 300SDL - PeachParts Mercedes-Benz Forum

cmac2012 · #1 07-04-2017, 04:16 AM

I deleted the thermostatic valve thingy but lately fuel leakaga has started anew. Alas and alack. I took a look and it wasn't hard to find. Fuel is seeping from under a couple of the flat metal things under the knurled nuts:

I have a viton set of O-rings on the way from Squiggle Dog. Not sure that some of those will be inserted here, I found a couple of older threads here, one mentions plastic bushings.

Anyone done this? I gather one needs a specialty wrench for the gnurled nuts, the multi toothed things.

Here's a thread from '06, he links to another thread in post #5.

Leaking Injector Pump at Fuel line to Injector -- OM603

sixto · #2 07-04-2017, 08:33 AM

If you're sure it's not dribbling from the injector line fittings, it sounds like delivery valve seal time. You need a splined socket for the delivery valve holders. It's easier for both access and keeping things clean if the intake manifold is off. You should replace the o-rings and washers. Some replace the springs. Mind which way the barrels are fitted. There's a notch around the barrel to orient you. The tightening sequence is key. It's something like 20Nm, loosen, 20Nm, loosen, 25Nm. The sequence isn't in the FSM so look for the post of the TSB by gsxr or advice of forum denizens you trust.

Sixto
98 E320s sedan and wagon

Diseasel300 · #3 07-04-2017, 11:41 AM

You need to replace the O-rings and copper sealing washers. Yes, you need a splined socket to get the delivery valve holders off. You CAN do this job without removing the intake manifold, but it does make it very tight.

Tightening sequence for the DV holders is 30NM, release, 30NM, release, 30NM, then final torque to 35NM. That's torque and release to 30NM 3 times, then final torque to 35NM.

If you do the tightening too loose or fail to torque and release, expect loud injector nailing or difficulty starting when the car has sat. Been there, done that.

If you're ordering parts, do the springs as well. They will have to come from a dealer, or one of the dealers who sells parts online. They're not expensive and you will notice the difference in length and stiffness.

Critical: Make sure everything is SPOTLESS (as in you could perform delicate surgery) in the area you're working. Any dirt that accidentally gets in the system can cause you problems later!

cmac2012 · #4 07-04-2017, 02:18 PM

Great advice. Not sure what the 'torque and release' thing is though. What, go around to each one in sequence and recheck it at the same setting?

I've read that the manifold does well to be taken off to put in new glow plugs. I had thought I might need new ones owing to no glow plug light and rough starting. But then you mentioned the relay issue. Also with the new starter I gnashed my teeth over, startup is really fine, so maybe my plugs are fine.

But dang, if I'm going to go to the trouble to pull the manifold, maybe I should go all marathon and do both.

Where does one get the splined socket? I guess I could search on that.

Diseasel300 · #5 07-04-2017, 02:35 PM

Torque and release means exactly that. Set your torque wrench to 30NM and tighten until you reach torque. Break torque (release/unthread/back-up) on the DV holder, then re-torque to 30NM twice more. Set the torque wrench to 35NM and do a final torque setting.

The splined socket is sold by the host of this forum as well as in various other places. I picked mine up on Amazon for less than $20. Considering how many times my DV's have been in and out of my car for various reasons, that socket has earned its keep.

If you have the manifold off and you have no idea how long the glow plugs have been installed, it wouldn't hurt to change them out and ream the holes. Make sure you install a new manifold gasket if you do take it off. If you aren't missing out or nailing loudly when cold-starting, you likely don't have a glow plug issue. In that case, I'd do the DV seals without removing the manifold. Little trick that helps: Drop the socket down over the DV holder, then snap the wrench onto it. It's easier than trying to get the whole thing in there at once.

cmac2012 · #6 07-05-2017, 03:28 AM

I have so much work now - feast or famine - that I like the idea of not taking the manifold off. I want to stop the fuel leak but I just don't have the kind of time to take on all three - plugs, manifold, and O-rings/washers. And it is starting well. There is, I gather, a chance one can run into a difficult glowplug extraction. Given that the starting is more than acceptable, if it ain't broke ...

Thanks for the explanation of torque and release. I can see how that would yield the best final position.

Maxbumpo · #7 07-05-2017, 09:14 AM

Torque and release (30Nm - 30 - 30 is correct): You don't need to back of very much, just loosen a bit. This is done to ensure (1) the correct torque is reached and (2) the aluminum body of the injection pump is not warped in the process. Final torque is 35 Nm, don't release the last 30 Nm before hitting 35 Nm.

Glow plugs: I agree with NOT changing these until required.

Other fuel system o-rings and rubber fuel lines: definitely change all these as well, especially the fabric covered lines between injectors.

Another item: the PCV tubing is an octopus that vents crankcase into each of the six runners of the intake manifold. It is probably all baked and brittle and will crack apart when you take the manifold off, so be prepared with new rubber parts for that as well.

Diseasel300 · #8 07-05-2017, 09:44 AM

Quote:

Originally Posted by Maxbumpo

Another item: the PCV tubing is an octopus that vents crankcase into each of the six runners of the intake manifold. It is probably all baked and brittle and will crack apart when you take the manifold off, so be prepared with new rubber parts for that as well.

Not on an OM603 it isn't. It's just a simple tube that runs from the valve cover next to the oil filler cap to the rubber boot at the turbo intake. You're thinking of an OM606.

Maxbumpo · #9 07-05-2017, 09:50 AM

Quote:

Originally Posted by Diseasel300

Not on an OM603 it isn't. It's just a simple tube that runs from the valve cover next to the oil filler cap to the rubber boot at the turbo intake. You're thinking of an OM606.

Doh! Correct, I need another cup of coffee....

cmac2012 · #10 07-05-2017, 10:47 AM

Quote:

Originally Posted by Maxbumpo

Doh! Correct, I need another cup of coffee....

No head smack warranted. Good advice above. I mentioned in another thread that the PO must have deleted the PCV at some point. I was unaware of the history of that part when I bought the car. I had read about the head cracking problems from the particle filter thingy and when I saw this non-stock looking part I enquired here and learned the news:

I have mixed feelings. I'm generally an eco-friendly kind of guy but I'm not sure I want to jump through hoop$ to reinstall a PCV arrangement, especially since it would probably result in some power loss. I have yet to try to adjust the alda on this - I did so on my '81 300SD about 8 years ago and experienced the power boost from it. I should research that more, not sure if doing something with that would be another layer of eco-criminality. My power is not bad, I have nothing to complain about.

But yeah, on the glow plugs, there would be some hard head smacking did I run into a small disaster with those. If it ain't broke, don't fix it. I don't have a Jay Leno auto-rebuild budget.

Diseasel300 · #11 07-05-2017, 11:58 AM

You're thinking of the EGR. The PCV (breather hose) is the plastic pipe that runs from the valve cover next to the oil filler cap down to the rubber boot at the turbo inlet. It is to suck fumes from the crankcase into the intake air to burn instead of just venting.

Regarding the EGR: Leave it alone. On these cars I doubt you'll see any real difference in emissions with it connected vs with it disconnected. At the age and mileage of these cars now, there are other factors dictating how "dirty" their exhaust is. What will happen if you reconnect the EGR is a gradual sooting up of the intake manifold. Over time, the engine will lose power and burn MUCH dirtier, producing more soot, and rapidly clogging the intake. My SDL was so clogged with soot when I got it that the intake runners were down to 1/2" holes bored through a solid mass of soot and goop. Talk about a mess to clean up!

Before I'm taken down in flames regarding the EGR as an emissions control device, I believe in emissions controls that work. EGR is a half-assed attempt at controlling emissions on the cheap. It may work fine when the vehicle is new, but over time it causes more problems than it solves, even on gas engines. Put some miles on the engine and you wind up with soot and buildup on the valves and intake manifold. If you don't think that increases emissions, think again.

cmac2012 · #12 07-05-2017, 01:38 PM

Ah yes, the EGR. I recall now. Similar to the PCV thing but different. I suspect you are correct on the inadvisability of hooking it up. Unfortunately I know practically nothing of the history of this car. The welds are really good on the bypass thing so there was some good work done on it here and there I'm guessing.

Point being on the history, for all I know they took off the manifold, saw all that gunk, cleaned it up and deleted the EGR.

So have you done anything with your alda?

Diseasel300 · #13 07-05-2017, 06:31 PM

I have a 3.5L IP on my car, so I have the ALDA turned way, way down. With the stock ALDA setting it was rolling coal like crazy, so much so that I was getting fuel dilution in the oil. Still not ideal and I'm on the lookout for a proper 3.0L IP for the car. I have a couple threads on this forum detailing the IP saga I went through on that car. The 3.5L pump got the car running and at that point I just left it!

It's easy enough to determine if you have a clean intake or not. Pull the crossover pipe and take a peek inside. If it looks like it's full of coal dust, you know it's probably worth pulling the intake and cleaning it out.

cmac2012 · #14 07-08-2017, 05:09 PM

Quote:

Originally Posted by Diseasel300

Torque and release means exactly that. Set your torque wrench to 30NM and tighten until you reach torque. Break torque (release/unthread/back-up) on the DV holder, then re-torque to 30NM twice more. Set the torque wrench to 35NM and do a final torque setting.

The splined socket is sold by the host of this forum as well as in various other places. I picked mine up on Amazon for less than $20. Considering how many times my DV's have been in and out of my car for various reasons, that socket has earned its keep.

If you have the manifold off and you have no idea how long the glow plugs have been installed, it wouldn't hurt to change them out and ream the holes. Make sure you install a new manifold gasket if you do take it off. If you aren't missing out or nailing loudly when cold-starting, you likely don't have a glow plug issue. In that case, I'd do the DV seals without removing the manifold. Little trick that helps: Drop the socket down over the DV holder, then snap the wrench onto it. It's easier than trying to get the whole thing in there at once.

Is this the one you referred to?

https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dautomotive&field-keywords=splined+sokcet+mercedes+fuel+injection

Would be nice I would think to have a 3/8 drive version, and shorter, but if it's not out there, l'il old me is not going to make it.

Diseasel300 · #15 07-08-2017, 06:37 PM

That tool should work. The one I have is a Kokon 4133, but the same tool. Mine is also 1/2". I use it with a 3/8" socket and a 3/8-1/2" adaptor.