I wish my W123 85 300D ran as quietly as my W124 87 300D.
Several times passengers were surprised to learn the W124 87 300D was a diesel. Granted, my W123 85 300D is battle scarred, having its engine pulled and replaced, and things have shifted and been flexed, and the exhaust, which if not properly aligned upon reinstallation, can be a source of diesel noise.
Anyway can anyone offer me any comments on killing diesel noise? The other week I replaced the Intake/Exhaust Gasket on my 85 300D and it helped. What are your ideas about--

1. Proper Timing of IP ?
2. Valves adjusted cold ?
3. Exhaust properly aligned ( manifold pipe from Turbo
doesnt sit close to starter motor, primary clamp is adjusted with new
rubber donuts ?
4. Engine Mounts ?
5. Rear Transmission Mount ?
6. Air cleaner rattle ?
7. Hood Pad ? I dont think so, my 87 is missing one and is still quiet
8 A LOUD STEREO--you wont hear the engine

as a test try running 3litres of virgin veggie oil.if this reduces the noise alot you can be more sure that the noise is combustion related i.e injectors

Marine Supply stores, like West Marine, carry a sound deading stuff that I used on my diesels floor board and firewall. It's made for engine rooms on boats and is about an 1 inch thick. I don't remember what it was called, but it made a huge difference on my wagon. The material is one side sticky, with 1/8 inch flexable lead and then 7/8 dense form...

Hello Carrameow
1985 W123 300D
1987 W124

1. Proper Timing of IP ? = Always a good idea.
2. Valves adjusted cold ? = Always a good idea.
3. Exhaust properly aligned, clamp adjusted and new rubber donuts) ? = Always a good idea.
4. Engine Mounts ? = If in doubt a good idea.
5. Rear Transmission Mount ? = If in doubt a good idea.
6. Air cleaner rattle ? = A good idea to fix it.
7. Hood Pad ? = Quieter with the hood pad = a good idea.
8 A LOUD STEREO--you wont hear the engine = Permanent hearing damage and is a very bad idea.

IMHO...

__________________
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/

This has been discussed before.
I'm sure if you do a search for sounddeadning
you'll have a few pages of info to diggest.

Louis.

It's called "SOUND DOWN" or SOUNDOWN........It can also come with a lead core and weighs like hell!

The easiest way to quiet your W123D is to mix up to 50% oil in your fuel. Vegetable oil, 2 stroke outboard oil, diesel engine oil, gas engine oil are all okay. Just make sure you use unused oil unless you filter the oil first down to at least 5 microns. The 616/617, turbo or not, will run just fine on heated to thin it straight oil, bio-diesel, straight veggie oil if heated to thin it or any combination of the above as long as the outside temp is above 50 degrees farhenheit. A bit more of the italian tune up is needed the more you run fuels other than diesel. Veggie oil at as little as 5% will quiet your engine noticably. I am now running 30% diesel engine oil, unused, as vessels I work with often change oil and leave the end of 5 gallon buckets for whoever wants it. The engine is very, very quiet. I do prefer veggie oil, as it produces very little exhaust smoke and smells great. Dino oil smells worse than diesel, and causes a bit more smoke.

every topic here has probably been the subject of Discussion before---I mean how many variations of questions are there about Diesel Engines...sorry maybe I drank too much coffee tonight and I am in a Debating Mood!!( I'm watching Bush vs Kerry)

Dude- you're the guy who posted the question.... and now it looks like your saying to the poster to check the search before posting?
Better find out what went into that coffee......

Irish Coffee..

I wasnt talking to you---anybody who is creative enough to use Veg Oil in a Diesel is definitely my FAVORITE---somebody else told me to use the SEARCH ENGINE--as a matter of fact i was talking about you last nite to a buddy at work.............keep up the science.

Try some of your Irish coffee maybe that will make it run better?

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

The 603 is a very quiet diesel, but I've heard 617s that aren't much louder.

Here's the rundown:

You MUST have

1) good injectors

2) good compression (that means proper valve adjustment and good condition valves and rings).

3) proper injection timing (fast is noisy)

4) good engine and transmission mounts (replace if not done in the last three or four years, makes a BIG difference not having the engine carrier pounding on the frame...

5) good engine shocks

6) Rack posistion screw adjusted properly -- and knowing that as it ages, you will get to the point that it will shake terribly at idle no matter what you do short of an IP rebuild.

7) A good hood pad is required, ditto for the sound insulation on the firewall and floorpan

8) good condition exhaust, properly hung. If you get the tranny hanger too "tight" (that is, too close to the tranny), the exhaust will drum badly. Loose stretched "donuts" will allow the pipe to drum on hte rubber body pads, and if hte pads are missing, it will drum on the floorpan instead.

9) a bad center driveshaft bearing will often sound like a bad muffler, drumming the floorpan at the rear of the driver's seat.

What kind of noise is bothering you?

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

that was precisely the answer I was looking for, thanks again