Newbie on engine sound - Diesl engine nailing or knocking sound?
 

My OM603 engine sounds noisy. I am not sure it is nailing or knocking. What are the differences? Any link to an actual video on the web? How about a spun bearing, what does it sound like?

Thanks

Try youtubing it, there are videos of 240D's with blown engines and normal engine sound. Change your oil/filter also.

At idle is your oil pressure capped? Take a video please, not enough information for anyone to reply.

really hard to tell the sounds from a video.
a knock sounds like someone is hitting the block down low with a hammer...
nailing sounds like someone is hitting the head with a hard wooden dowel...
it's not really how the sound sounds, but WHERE the sound is emanating from...

X2 Time to get your big screwdriver out & use it as a stethoscope.

The reasons I asked is that I kind of did a low budget 'ring' job. I removed the head and lower oil pan and pushed all the pistons out. Cleaned the piston groves, honed the cylinder with a HF cheapo honing tool, replaced rings and put it back all together. The car is now running good. I have done about 100 miles on it since I put it back in service. It idles smooth, no blow-by. The blow-by was so bad before that oil would squirt all over the engine bay if I removed the engine oil dip stick. Now it is OK with dip stick removed, oil cap kettle test passed. Very little or no smoke from tail pipe. So I believe all is well. I have yet to do a compression test.

However, the engine purrs then gives a 'tick' 'tick' sound on and off at idle. I think it is from the top, not down below. Revving the engine does not give any ticking sound. So I am not sure whether the engine is healthy or not. I think it is OK as it drives smooth and has more power than before.

tick tick could be from the hydraulic lifters... what's your oil pressure at idle?

That's the classic 603 lifter sound...........comes and goes..........cannot determine why.

Engine is fine.

Just ignore it or spend the time and money to remove the camshaft and pull all 12 and test them.

Thank you guys. The oil pressure is at 3bar when first started then drop back to 1+ bar in normal idle. The oil pressure definitely is OK. I will change the oil after 500 miles and see how it goes.

VSTECH-
Could you clarify why you were asking about oil pressure at idle? How does that relate to hydraulic lifter noise? I suspect I have a similar click as the OP, so I am trying to diagnose it (without going to the length proposed by Brian of removing them all).

Also, for the OP and myself, is it really true that running synthetic oil can quiet the lifters or is that MB folklore? Thanks.

It's true if it works for you.

It's folklore if it does not.

just wondering if he had low oil pressure at idle, since he pulled the pistons, but did not mention replacing the bearings.

I can see if the lifters were sticking from varnish or thick oil, changing to synthetic could free them up.
I use nothing but synthetic on my 603 powered cars...

I did not replace the Rod bearings as they look OK.

Haha. Truer words have rarely been spoken.