Background:

1985 300SD with approx. 380K miles. New monark injectors installed 200 miles ago. Car was noisy before new injectors installed. I thought the noise was injectors so replaced them. Engine does not burn oil. Engine does not smoke at all. Engine very smooth. Engine has plenty of power. Vacuum and glow plugs good.

A friend and I used a stethoscope to isolate the noise. All regions of the engine were quiet, except for the region on top of the cam cover between #4 and #5. The noise coming from that area appeared to be the area of interest.

I have recorded two videos. I Looking for suggestions on what to troubleshoot next and how serious you think the problem is.

Take a look at these videos. The sound quality is representative of
what is actually happening. At the end of the first video, I sat the
camera on the dash and you can see that it didn't even move. Car is
very smooth. There is a little light smoke out of the exhaust but
that is probably due to the very cold temps here.

Video 1
http://www.youtube.com/watch?v=v5aNCHAQm_Q

Video 2
http://www.youtube.com/watch?v=_K675DzBCFE

It sounds normal except for what sounds like injector knocking...let it warm up too - these cars can be a lot noisier when cold. Did you have the injectors balanced and tested before you put them in?

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

monark injectors set to 140 bar within spec. car makes same noise weather cold or warmed up.

It doesn't sound to bad, just a slight "diesel knock". It is possible that there is a bit of water in your fuel, which could cause that random knock.

Are your valve set to spec?

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

Sounds like a MB diesel.

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

I agree, just a little injector knock; I wouldn't worry about it.

As I said, I used a stethoscope. Injectors are quiet. The noise is coming from on top of the cam cover between #4 and #5. I haven't disconnected the delivery lines to #4 and #5 to see if noise stops, but I am almost 99% positive that it is not the injectors. I will do that tomorrow.

When were the valves last adjusted?

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

adjusted valves in october 2009. thought that might be why it was making noise then. noise persisted. led me to the injectors next, which were also replaced.

Have you swapped injector positions to see if the noise follows?

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Just for kicks, tomorrow, I will have time to disconnect injector #4 and see if the noise subsides. Then I will do it to #5 and check. I am just wondering if it could be broken spring or worn lock nut or something on the cam tower.

It is quicker to remove the valve cover for a look-see than to swap injectors, but loosening the fuel lines is even quicker.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Have you checked you air filter mounts? They are between 4 and 5 and make noise when broken.

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1983 300SD

air cleaner bracket is good. all good bumpers on it, too.

disconnected #4 and #5 injectors. noise still there.