Someone mentioned this site in a similar post

http://injectors.150m.com/

I know nothing about them and they sure seem expensive but if the injectors are as good as they sound it would go a long way to eliminating the injectors as the source of the knock. Maybe.

That's TomJ's small business. Last time he was saying he doesn't do rebuilds anymore because he can't find decent new nozzles (they're all made in India now). In fact he was thinking to get out of this business, but I don't know what he decided to do. I'm gonna try the Bosch rebuilt injectors anyway because it's my only option. Maybe they won't meet Tom's standards (or mine) but hopefully they will be better than what I have now.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

I'm surprised to read many of the 603's here knock, or nail as much as they do! Hatterassguy boasts that his begins to sound like a gas engine, after 2000 rpm!

WoW, I guess I'm just lucky? I'm not posting here just to brag, I thought a few of you guys would be surprised to hear a 603 that sounds the way MB intended. At idol, in my car, you can just barely tell that is a diesel, and the second you touch the gas pedal, you cannot hear any clatter at all, just a faint whine of the turbo spooling up and the humm of the tranny up out of 1 st. gear.

I would be alarmed if my car only began to quiet down after 2000 rpm.

I know these engines can run quite impressively and quiet too! So don't loose hope!

I hope you have some luck with you new rebuilds..................Steve

That it exactly how both of my 603's are, and my sister's, and my dad's. Tiny burble at idle that turns into dead quiet, gas-engine-like smoothness just above the 630rpm idle. I would very much like to know what the cure is for the few 'noisy' 603's out there.

My car is only noisy when idling, blip the throttle and it sounds like a gas engine with a throaty note to it, no. (can't hear the turbo and my friend said my car sounds like a monster)

I'm really confused as to what the problem is.

__________________
Jason

00 Subaru Legacy (fun wagon)
96 Nissan Sentra (disavowed)
82 300SD (garage queen, will run again hopefully)
87 300DT (Gone: 10/15/2010)

I should have said my lifters quit down as the rpm's rise. I'll have to pay more attention today to when they do this. Until the rpms rise mine ticks away!

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Lance,

My 603 sounds like your 603 on startup and idle, and possibly a bit queiter at speed. I'll quit worrying about the way it sounds.

Do you have the sound panels installed?

Wray

No, I've been a slacker with reinstalling the noise panels on the SDL. They are up in the garage attic. The insulating panel on the TDI only has 4 bolts and 2 star washers holding it up. Surprisingly, I do have that one still installed.

__________________
Lance Allison
Lance@LanceAllison.com

Current:
11 MB S550 4Matic, 55k miles, Designo Black/Black
14 Ford F150 XLT Lariat Crew, 73k miles, 5.0
Coyote V8 4x4. Black/tan.
09 GMC Envoy Denali, 5.3 V8, 4x4 SWB. 38k miles,
Jewel Red/Med Gray.

Gone:
87 MB 300SDL, 320k miles, Astral Silver/Blue.
98 VW Jetta TDI, 488k miles, Classic Green/Gray.
85 Olds 98 Brougham FWD, 4.3 DIESEL V6, 80k
miles, 3x Gray.

MBCA Member, Chicago Region

I just listened to Lance's clip. His engine sounds pretty normal - just a little loud, almost like the hood was up the whole time. But that may be due to the recording equipment used, placement of microphone, lack of sound encapsulation panels, etc. No weird knocks, pings, or rattles. Put another way, Lance's sound clip doesn't make me think "whoa, something's wrong there!" like I thought about DA's engine. I wish I had an easy way to record my engines...

Use a tape recorder, feed the output to your sound card input jack.
Windows XP has the software to cut and compress the audio file.
Keep experimenting with the software until you get it right.
You know how to post the file.
Have a great day.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

What a great post, the sound posts are very helpful.

Question for Sarafn and GSXR: How do your engines sound compared to the Lance Allison sound clip?

Thanks!

__________________
87 300DT 140K miles
85 300DT 265K miles (sold)
95 E320 48K miles
93 RX7 (son's) 100K miles
04 BMW 330xi 16K miles
05 Porsche 997 S 4K miles

Mine sounds pretty close to Lance's clip - I think. Mine seems a tad quieter but as mentioned before, that could be due to a number of variables. The general sound is very similar though (unlike the original MP3 posted with the weird noises!)

Interesting thread.
I have exactly the same noise but only when starting from cold and only at idle. It is quiet at higher rpm's and once warmed up but has a loud 'rap' (nailing?) at idle when cold.

My mechanic seemed to think I may have some moisture in the fuel - the car wasn't used for a while before I bought it - but I have run through 5 tanks of fuel since then, all but one purchased at high volume truck stops. I drove the car back from Texas over 2 days (1670 miles) at an average of 65mph (excluding stops) so it had a good long run at normal operating temperatures and highway speeds. Shouldn't any moisure have dispersed by now?

Should I try some additives to clean the injectors and disperse any moisture, or should I look at mechanical solutions? BTW my Tensioner and shock are both brand new so it definitely isn't that.

__________________
1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown

In your case, I would:

1) Replace the fuel filters if they are old
2) Do regular Italian tuneups (lots of full-throttle redline runs)
3) A can or two of Diesel Purge wouldn't hurt

Remember, at cold idle there is a lot more diesel noise, which is normal - but it shouldn't be a harsh nailing noise. (It's all subjective and hard to describe!) It may take a few thousand miles of hard driving to clear out carbon, etc, especially if the previous owner drove the car sedately.

Fuel Filters were just replaced prior to my drive home.
I'll try a can or two of Diesel Purge and see if that helps.

I admit to being new to Diesels, but my mechanic (a local M-B Specialist) is very familiar with them and he certainly thinks the cold idle 'rap' noise is excessive.

__________________
1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown