OM603 Noise cyl 1
 

Hi,
I live in France and I have a 1995 S Class W140 S350 I am very happy with except for one thing.
This is the third engine in this car, I replaced the original 3.5 turbo diesel with used the 3 liter turbo diesel. It performed excellently for about 20 000 Km and now has developed a very nasty ticking noise.
To find the cause I have done the following:

• Checked chain stretch – OK
• Checked hydraulic valve lifters – OK
• Checked injection timing – OK
• Checked Injectors – OK
• Checked vacuum pump – OK

With a special automotive stethoscope I have found that the sharp metal ticking times to the valve train and comes from cylinder nr 1 it is loudest when placing the stethoscope on the fuel line to injector number 1 (very loud ) Fuel additive to raise the cetane number had no effect, adding automatic gearbox oil (half liter, advised for faulty hydraulic lifters) no effect. The ticking is least when running stationary and gets louder when accelerating.

My remaining options are, can piston be touching the prechamber nozzle, is something lose in the prechamber, pre-ignition because of deposits in prechamber on glowplug.

Engine runs very even, no smoke (Black blue white or other color) uses no oil, runs economical, temperature is normal, power is OK

SO WHAT CAN IT BE??? Please help me , if I take it to the Mercedes garage they are going to start taking the head of and renewing everything and it is going to cost me an absolute fortune. ( Mercedes service stinks here in France. The Mercedes cars are OK but sevice is rubbish)

I would be VERY grateful for any suggestion. ( Except putting a match to it, or running it of a cliff)

Regards Graham;

tick tack
 

i had the same nasty tick near where you say it is ans a tech friend of mine told me to change the oil a couple times , i did it went away.....

Thanks for advise
 

Hi Zues,
Thanks for the information, How many times did you change the oil and what caused the noise? Did your tick also remain when you revved the engine, or did it get less with more revs?

Regards Graham

Have you checked the pop pressure and spray pattern of the #1 injector to be certain it is operating correctly?

Swap the #1 injector with #5 and see if the noise goes with it! My $.02 Don

Could just be a lifter. If it is, it's not really worth worrying about. Swap the injector if you must, but check the others with your stethascope first. If they all make the same sound, no use changing them. IIRC, if something was in the prechamber, it wouldn't fire correctly and there would be a thumping sound, not ticking.
If it's a lifter, one Mercedes tech I talked to said that it wasn't worth the repair, unless the engine was already apart, and that not replacing it wouldn't cause any damage. Just my 2 cents.

HI,
Thank you all for your advice, it is REALLY appreciated.
First thing I did was take the injectors to a Bosch service place, the spray pattern and opening pressures were OK. I changed nr1 injector with Cyl nr 6 injector, no difference.
I had the valve cover of and with a warm engine pressed each valve lifter and measured the space between cam and lifter with cams pointing up, none had a space that would accept the 0.4mm feeler.
If it was the hydraulic lifter of Cyl nr 1 would'nt I hear it when I take the oilfiller cap of while the engine is running?
Regards Graham.

my guy said mine was a lifter noise , changes oil twice and cured it . my tick started at higher rpm on the highway and went away on its own the first few times, but than stayed. valvoline 15 - 40