Ok...I recently acquired another 603 car and got a video of my current one vs this one. They sound very different and I would like to through around some thoughts as to why, and hear what you think as well. I will give info on what I know of each of the engines.

1st Engine - 1987 300TDT Wagon, 185k miles, running on Mobil 1 TDT Synthetic since about 155k, fuel filters changed, injectors pop tested and ok, ALDA removed, new style vacuum pump, no vacuum leaks, making full boost, ELR (Idle control) set at 5. Oil pressure stays above 2, A/C Works but not on in video.

2nd Engine - 1987 300TD Sedan, 227k miles, running on 15/40 dino (unsure of brand and not sure of history, primary fuel filter changed, unsure about injectors, ALDA intact, old vacuum pump, unsure about vacuum leaks, unsure about boost, ELR (Idle control) set at 7, Oil pressure is at 0 until I rev engine, A/C status unknown.

All this is to give some objective information about each engine and to speculate a bit...then hopefully at some point I am going to clean up the second/dirty one and make it run like the first, doing little things at a time and seeing what changes things.

It sounds as if the first one idles at a much quicker and smoother rate, whereas the second seems to idle slow and less smoothly, even though the second one is at 7 on the ELR. What are your thoughts?

Youtube:
http://www.youtube.com/watch?v=uF20i_Ny5U0

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1987 300TDT - 195,000 (Original #14 head)
1993 190E 2.3 - 105,000
1981 300D - 250,000

Put pressure on the top of the belt tensioner damper heim end to see how much it's contributing to the difference in sound.

Does the idle rpm respond to changes in ELR setting?

Sixto
87 300D

Good call! Tensioner however did not seem to be contributing to noise. As for the ELR, that is also a good point. I was going to change it again and see, but I had already taken the batter out to start mine up. I will look into that next time.

Also, I forgot to mention that the oil pressure in number two is at 0 until I rev engine.

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1987 300TDT - 195,000 (Original #14 head)
1993 190E 2.3 - 105,000
1981 300D - 250,000

The 2nd one looks physically not taken care of. And the K&N sticker on the air cleaner says it all. Probably been breathing dirt for 50K....it will ruin an engine.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

It takes a lot, short of overheating, to kill these engines. I am gonna get a new filter in there soon...who knows, maybe the K&N was swapped out.

__________________
1987 300TDT - 195,000 (Original #14 head)
1993 190E 2.3 - 105,000
1981 300D - 250,000

Overheating is not the only way to kill an engine. Running dust and junk through the air intake is a sure way to slowly kill a motor too. A K&N passes FAR more engine wearing junk through the cylinders. MB designed the filter to be perfectly mated to the engine, a redneck style K&N slapped on is only going to decrease the precision.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)