Hi have a 1976 240d that I acquired 1500 miles ago. Appears to have a great engine...thick stack of prior service records with 3-5k oil changes for life of car, 1/3 quart of oil used in last 1500 miles, engine is spotless, starts up right up and runs great.

However, I have a new noise. I think it may have started several days ago after my foot slipped on the clutch pedal and the car stalled. Several days ago, after I had driven to work and had started the drive home in the afternoon, the engine made a sort of rattle noise..it wasn't the tick..tick..tick of valves, more a an unorganized slight rattle. It went away after a couple of blocks of driving.

Since then I have noticed that after I startup the engine and for the first few blocks of driving (after a couple of minute warmup) if I accelerate some of the time I will sometimes get the rattle noise. I never get the noise after the engine is fully warmed up, and sometimes I do not get it when it is cold.

This morning (It was colder last night (45 degrees as compared to 55 degree nights before) I got a more pronounced louder rattle right on startup that went right away (2 seconds)...I was able to produce a small bit of rattle after I took off with mild acceleration...

Any ideas? Timing belt? Injectors? nothing appears to be loose and it is difficult if not impossible to reproduce this behavior in the driveway with the hood up.

Thanks

It had sat for about 4 hours and did not make noise on startup but when accelerating had a sort of pinging/metallic noise?

Makes me think that this is fuel injectors? If so, why the more metallic louder rattle this morning at startup? Is that noise possible with injector problems?

I am new to this diesel thing...lots of DIY on gas engines...

I just went and filled (from a 1/4 tank of diesel) the gas tank with 99% Biodiesel. This is what the car was running on when I got it. It seemed much quieter. I am going to see it this fuel makes a difference with the "rattling"

Hi, You might be better off post these questions on the diesel list. Every diesel I hear sounds like its going to explode any minute!! Seriously if you do a search for "nailing" in the diesel list you will find lots of info.

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

Have you tried opening up the engine bay when it's cold and isolating the location of the noise by ear or do you hear it from inside the cabin? Maybe slowly bring up the revs by pulling the linkages to reproduce the noise since the engine vibrates at different rates with rpm's.

I had a strange rattling noise in the engine bay when I misaligned the oil bath filter into the silly rubber feet ...darned thing took 20 minutes to shoe in both "forks".

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1974 240D 3.0L 4(M) - 250K -OM617.910 + 300D FW + Rajay turbo power!
1977 6.9 3(A) - 84k