loud clicking sound coming from cylinder #3? - PeachParts Mercedes-Benz Forum

Grdenko · #1 12-08-2003, 10:40 AM

for the last couple months my engine has been making a loud clicking sound. the sound speeds up and slows down with the speed of the engine and i can hear it if its in idle and i have my window down.

last night i decided i wanted to figure out what it was so i put my ear close to the engine to find out where it is coming from.

it seems to be coming from the 3rd cylinder, or around there. i put my finger on the fuel line for that cylinder, and i could feel the pulse very distinctly. i could feel it on the other cylinders as well, but it wasnt as hard.

could this be my fuel injectors? should i have them adjusted? if thats what i need, is it a job i can do myself?

thanks alot

#2 12-08-2003, 11:27 AM

I have almost the same thing in my TD. Do a search for my threads called "Strong Nailing" and "Strong Nailing update"

Good Luck.

Grdenko · #3 12-08-2003, 11:50 AM

from what i read, i take it you havent figured out the problem yet. too bad.

my car has been doing this for about 3 months, does anybody know if this could eventually lead to catostrophic failure? if i do have the mechanic work on it, ill let you know what he thinks it is.

thanks

luckys420 · #4 12-08-2003, 12:05 PM

from my understanding the injection pump creates a ticking sound under normal conditions. and nailing sounds more like a loud knocking. dont take my word for it, thats just what i have gathered from reading multiple posts on this site from many many searches, but i may have wrongfully interpreted the posts.
lc

Rick Miley · #5 12-08-2003, 12:15 PM

Grdenko, have you tried a Diesel Purge?

adamb · #6 12-08-2003, 12:30 PM

I had the same thing on my 85 300d. I used my stethascope to narrow it down to the number one cylinder, then I cracked the injection line to that cylinder and the nailing sound whent away. These injectors are only a year old, too! I then got a used injector for ten bucks and the sound is gone!
Many thanks to all those great people on this forum who provided me with the know-how to do this.
Adam

Grdenko · #7 12-08-2003, 01:16 PM

actuall, now i think it is the #2 cylinder (or is it #4) second one from the back. the sound is usually much quieter, after the engine has warmed up. sometimes it can be loud even when the engine is warm. it goes in and out sometimes.

the sound is definately more of a ticking than a knocking, but at times it can be very loud.

i havent done diesel purge yet, but im going to order some.

how do i "crack" the injection line? does that mean disconnecting it and capping it?

thanks for all of the help

Rick Miley · #8 12-08-2003, 01:20 PM

Crack means just loosen it a bit.

#9 12-08-2003, 05:26 PM

Quote:

Originally posted by Grdenko
from what i read, i take it you havent figured out the problem yet. too bad.

I have not solved it yet. Saturday, I ran my tank almost empty and filled it with 3 gallons of soybean oil. It made the engine very much quieter so that I could listen more exactly what the sound was. I replaced the pressure valve assembly which greatly reduced the sound and gave it much more power now, but it did not get rid of it at all. Anyway, running on sybean, I could tell the sound has a much more mechanical nature like actual metal-metal heavy tapping. At this point the last thing I can do without taking off the head (Which won't happen as I don't have the time/cash/tools to do it), is take off the lower oil pan on my next oil change and have a look at all the bearings I can get to.

If that fails I will just have to live with it until it blows up

It's lasted 8 months now, so I'm sure it will be fine.