OM603 Delivery Valve seals replaced, jury still out - PeachParts Mercedes-Benz Forum

renaissanceman · #1 09-30-2018, 01:50 AM

In my quest to eliminate air bubbles in my return lines, and hopefully smooth out some cold engine injector nailing, I (finally) took care of the delivery valve reseal job today. New crush washers, o-rings and springs.

At some point before I owned the car, someone had replaced the o-rings on valves 1, 2, 3, 4 and 5 with some type of pale cream colored o-ring that was slightly too big. They also seem to have greased the threads pretty liberally, which made for a lot of greasy debris floating around in the pool of diesel after removing the valve cover (no idea what that part to which the injector lines attach is called). I pippetted as much of it away as I could, and replaced it with a 50/50 mix of kerosene and two stroke oil that I had been pre-lubing the new parts with. This made me very nervous after trying so hard to be "surgically" clean.

Anyway, after servicing all 6, she fired up after about 10 seconds of cranking. What a racket! Once the engine would run without applying the accelerator (another 20 seconds or so) The nailing was pretty bad at idle, but the idle was also about 500 rather than the 650 or so it usually is.

I went out and topped off my half tank of #2 with 8 gallons of Propel HPR and 8 ounces of 2 stroke oil and then drove on the freeway at 75mph for about 10 miles. The nailing got a lot better after that, but it used to always go away completely after about 10 miles.

So we'll see if it helped anything. At least I seem to have done no harm by letting all that greasy garbage into the valves. It seemed to be unavoidable, so I shrugged it off and just continued resealing at the time. Hopefully a few good hard runs on the highway will clear anything that might be remaining in the valves and/or injectors.

I'll update as I have more miles on the job. Now to tackle the exhaust manifold flex coupler to get rid of the exhaust leak, and all the major jobs will be done on this car after 4 years of ownership and lots of wrenching!

vwnate1 · #2 09-30-2018, 02:58 AM

Keep us posted please.....

Diesel911 · #3 09-30-2018, 12:13 PM

People have experienced nailing for several 100 miles after replacint the delivery valve O-rings.
Nailing after IP O-ring change
Possible cause of “nailing” after crush washer and "O" ring replacement - PeachParts Mercedes-Benz Forum

More Nailing List of causes
NAILING - Page 2 - PeachParts Mercedes-Benz Forum

Nailing Caused solved by Changing Delivery Valve Seals
A Question for the Injection "Masters" - PeachParts Mercedes-Benz Forum

Nailing stopped after solving air leak or removing air
Runs Rough In The Morning - PeachParts Mercedes-Benz Forum

Note the white greasy stuff sounds lie Lubri-plate (don't know if that is the correct spelling) some mechanics use that on nearly anything that needs to be lubed like Head Bolt threads and so on.

Diseasel300 · #4 09-30-2018, 02:56 PM

Did you torque the DV holders correctly? There is a tighten/loosen cycle you go through to make sure the washer seats correctly. The final torque value is critical.

As mentioned above, if any of the DV plungers were disturbed (and it's hard not to), you can potentially have a bit of nailing for several days afterwards.

And of course there's air issues. If there's air in the system, forget about the DV's, you need to find and cure the air ingress issue first.

renaissanceman · #5 09-30-2018, 07:27 PM

After 25 miles of driving, the nailing has settled back to nearly where it was before the change, and my idle and off the line power seems to be slightly improved. The delivery valve plungers did slide around a tiny bit on a couple of them.

I torqued and loosened twice, and then settled at 26ft-lb for the 3rd torque. This was through a universal joint, so the value may have varied a touch (I couldn't get the half inch drive torque wrench into where the DVs were...

On the air -- the fuel thermostat was a large issue, and I've since bypassed it (about 2k miles ago). Where else should I look for air getting into the line? O have a lot of air in my return lines pulsing back and forth...I was under the impression that the DV o-rings could introduce a ton of air.

Diseasel300 · #6 09-30-2018, 07:51 PM

Unless the DV O-rings were just pouring fuel on top of the IP, it's unlikely to be your air source. The O-rings on the DV holders are a secondary seal.

You already bypassed the most common source of air ingress - the fuel heater thermostat.

Other common sources of air leaks are the crush washers on the fuel filter housing, the O-rings on the nut on the fuel filter housing, the flare nut on the lift pump, the O-rings in the lift pump itself (I wrote a whole thread on my saga with said pump), the rubber fuel lines in the engine bay, and the clamps holding said rubber fuel lines.

A lot of folks swear by 5/16" fuel line in the engine bay. I guess I'm one of the minority that absolutely could not get it to seal adequately on my car, no matter what I did. I ordered the correct 7mm fuel line and haven't had an issue since. Another thing that makes a difference is the clamp you use - make sure you use fuel injection hose clamps. Worm drive clamps WILL leak air (ask me how I know!).

renaissanceman · #7 09-30-2018, 08:33 PM

DVs were lightly seeping. Probably not the source.

I replaced the fuel filter in 2014, and come to think of it, that may have been about the time that I started getting air ingress...or at least noticing it. I have the o-rings for the lift pump on hand, I should probably replace those.

I also have a good bit of 5/16 fuel line on this car, and probably a few worm clamps from my semi-emergency autozone parking lot fuel preheater bypass. I will have to order some of the correct line and install and replace any worm clamps with the fuel injection hose clamps I have gathering dust in my garage.

Do you have a link to the thread you made on the lift pump? I remember reading it a while back, but I don't have it handy.

What about connections at the fuel tank? I have not even looked at those connections to this point, but I do remember that the original fuel line I replaced while bypassing the fuel preheater was quite cracked at the connection points.

Diseasel300 · #8 09-30-2018, 08:50 PM

Here is my thread on the lift pump O-rings:
http://www.peachparts.com/shopforum/diesel-discussion/383438-om603-602-601-lift-pump-re-seal-o-rings.html

If it's been since 2014 that the fuel filter was last changed, it's probably due. Good time (and excuse) to change the O-rings on the filter bolt while you're at it.

The rubber lines back at the tank are worth a look. If they're oily or cracked, time for replacements. If they're dry and look ok, probably can ignore them for now and focus on the more common under-hood stuff. They're not subject to the heat and stress of the engine bay and tend to last longer. I pulled the originals off my SDL back in 2016 when I R&R'ed the fuel tank and they were still fine but I replaced them anyway.

dieselbenz1 · #9 09-30-2018, 09:19 PM

5/16 fuel lines were also problematic on my car and that caused air to be detected in the return lines. I did use fuel injector clamps but they needed retightening every 6 months. I've been running 7mm hose for over a year now and no issues.

renaissanceman · #10 09-30-2018, 10:06 PM

I checked and most if not all underhood fuel lines are 5/16 and are attached with the original fuel injection type clamps.

The fuel filter may be from 2014, but I think I have only put 8,000 miles on the car since. I can't remember whether I replaced the o-rings or not, but I'm guessing I did because I'm usually pretty good about replacing any seals I come across when servicing other parts -- yesterday I found a metric o-ring assortment in one of my boxes of Mercedes parts from my last move that would have been packed up shortly after replacing the fuel filter.

The first order of business will be to find some metric line to buy to replace all the new 5/16 line. I thought that the stock line was 7.5mm though?

renaissanceman · #11 09-30-2018, 10:12 PM

I shot a quick video of the idle 25 miles of driving after the re-seal job. The car had been driven about 10 miles 2 hours before this video was shot.

https://www.youtube.com/watch?v=NXxNivimpjA

renaissanceman · #12 10-02-2018, 06:53 PM

I measured a new Wix 33006 inline fuel filter and found the following:

Inlet:
Tapers from 7.60mm to 8.10mm over a 25mm barb length.

Outlet (90 degree):
Tapers from 7.95mm to 8.10mm over an 18mm barb length.

The Wix site specifies 5/16 fuel line. These two things lead me to believe that 7.5mm fuel line is appropriate. I'll order some from Pelican -- they have braided and non-braided. The price is close, so I think I'll just buy braided for a higher quality look.

Sidenote 1: the Wix filter is made in Russia, which is outside the China bubble which is pretty cool.

Sidenote 2: The nailing is a little better after another 10 mile drive (city miles). So far it's 50 miles post re-seal. I think a good hot run on a mountain highway for a few hundred miles will help a lot. I'll probably take the Benz out to the coast next time I go to give it some hard driving on the passes.

Maxbumpo · #13 10-03-2018, 01:55 PM

Quote:

Originally Posted by renaissanceman

I torqued and loosened twice, and then settled at 26ft-lb for the 3rd torque. This was through a universal joint, so the value may have varied a touch (I couldn't get the half inch drive torque wrench into where the DVs were...

Mmmm, not good enough. You may have to remove the intake manifold so you can get a clear shot at each delivery valve with no universal joint. Painful I know, but if you want to make sure you get a good result, you've got to do the job right.

I did pretty much exactly what you did but only with one delivery valve on my OM603. I could not get the torque wrench to fit under the intake manifold, and I didn't have the time to R&R the manifold, so I did my best. I've got a bad knock like your engine at idle, it goes away completely once the RPM climbs over 1000.

renaissanceman · #14 10-03-2018, 02:21 PM

Quote:

Originally Posted by Maxbumpo

Mmmm, not good enough. You may have to remove the intake manifold so you can get a clear shot at each delivery valve with no universal joint. Painful I know, but if you want to make sure you get a good result, you've got to do the job right.

I did pretty much exactly what you did but only with one delivery valve on my OM603. I could not get the torque wrench to fit under the intake manifold, and I didn't have the time to R&R the manifold, so I did my best. I've got a bad knock like your engine at idle, it goes away completely once the RPM climbs over 1000.

I'll grab a 3/8" to 1/2" adapter today and I should then be able to get my smaller torque wrench under there...Removing the manifold is a PITA (been there, and didn't know about delivery valves at the time..)

I ordered the 7.5mm braided fuel line, so hopefully that will solve my air in the injection pump issues...which may also solve the nailing. We shall see.

vwnate1 · #15 10-03-2018, 06:15 PM

O.K. ~ that clear plastic intake screen is cheap and Pep Boys stocks them in Purolator brand for $4, O'Reillys has both Wix and cheap brands for about the same .

The Pep Boys ones don't have the tapered ends but that's not a big thing, -DO- use the proper #13 band typ hose clamps and carry a spare in the glove box ! .

The crud (if any) will settle on the underside, inside where you'll miss it unless you tilt it up to look every time you check the oil .

ANY coffee grounds looking stuff in there no matter how slight means FUNGUS IS GROWING so if you see any, immediately add some brand of Diesel fungus killer ~ not just Diesel Kleen etc.

That engine sounds sweet to me but I'm old and like the rattle of vintage Diesel engines .