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

renaissanceman · #1 09-30-2018, 02:50 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!