603 engine tap - PeachParts Mercedes-Benz Forum

C Holmes · #1 10-22-2005, 06:44 PM

I have a 300TDT and when I start and let idle I can hear a tapping in the engine. If I run on the hwy for awhile it goes away. I assume that this could be a hydraulic lifter. If so is this easily repaired for a DIY er?

t walgamuth · #2 10-22-2005, 06:46 PM

hydralic valve adjusters are sensitive to oil. quality and probably cleanliness as well. a change of oil brand or if your oil happens to be dirty might be causing the problem.

tom w

Hatterasguy · #3 10-22-2005, 07:43 PM

Mobil 1 or Amsoil seems to help a bit, but usualy replacing them is the best fix.

I don't know the exact procedure because I havn't done them yet on my car. But you need to pull the cam thats about it, depending on your skill level it could be a diy job.

#4 10-22-2005, 08:02 PM

Most common knocks, pings, bangs in a 60X are:

1. Injector, or more than one, commonly referred to as "nailing" the sound is similar to hammering a spike into an oak plank. Can be detected by backing off the nut atop each injector from fuel supply tube. If no nailing sound when you do this you've found the noisy one!

2. Hydraulic lifters..almost impossible to hear which one is tapping. Switching to 5-40 synthetic helped stop several violators in my 603, but one tapper always returns! Running the engine up to 4500 rpm for a short blast (in gear) will stop tapping in my engine for 100 miles or so, but as mentioned, one always returns. The cam has to come off (special removal sequence..see service library for sequense) after the cam is off you just take a magnet and pluck them out. A weak one will compress in your fingers. Here is a link for the service library http://skinnerbox.steaky.org/Service/Library.html

3. Belt tensioner...This sound is erratic, more like a high pitch tapping with no rhythm and sounding from the top front area of the engine. It is actually the bearings inside the tensioner grinding around in their worn state and is common.

4. Rare is a broken GP, or piece of, inside the pre-combustion chamber, but I have read here that it does happen.

5. Even more rare is rod or wrist pin knock, and I have never read here about such with any of these MB diesels, but with maybe one exception regarding the 350 SDL, AKA "Rod Bender"

rdanz · #5 10-23-2005, 12:53 PM

You mite wanna change the two small o-rings that are near the bottom of the oil filter center bolt these have something to do with oil going to the lifters.

#6 10-27-2005, 10:48 PM

Quote:

Originally Posted by rdanz

You mite wanna change the two small o-rings that are near the bottom of the oil filter center bolt these have something to do with oil going to the lifters.

Yes, I have replaced the rubber O-rings, got them from the dealer. The old rubber O-rings were hard and brittle, but there was a slight rise in oil pressure indicated on the guage, but did not seem to have any effect on the single lifter that taps only before fully warmed up. After the engine is at 80 c, it is impressively quiet and without tap.

andmoon · #7 10-28-2005, 05:36 AM

Are noisy lifters harmful? I had a noisy lifter in my gasser and was told that one that comes and goes is okay to leave.

rdanz · #8 10-28-2005, 09:01 AM

Quote:

Originally Posted by BusyBenz

Yes, I have replaced the rubber O-rings, got them from the dealer. The old rubber O-rings were hard and brittle, but there was a slight rise in oil pressure indicated on the guage, but did not seem to have any effect on the single lifter that taps only before fully warmed up. After the engine is at 80 c, it is impressively quiet and without tap.

Are you sure the taps are lifters it may just be Diesel clatter that you get when the engine is cold.