Could be that I was incorrect remembering exactly what model years and range of individual cars that TSB covers. According to the post you've referencedit would be cars built in 92 and 93 July 92-July 93, not just 1993 cars.

But I would point out that the TSB info in that thread is at least 13 years old since it was posted on the forum so there might be another TSB that has come out in the intervening years since that was done.

I would also put forth the other pertinent info from a few posts earlier than the TSB info.

post # 5:

"I just today looked at a "'91 300D Turbo - Blue, 178K mi, 40K on reblt eng, CD, sunroof, maintd, all rec. $7500".
Nice car, but the reason for the engine rebuild was the timing chain broke. "

post # 8:

"I have a 91 300D 2.5 with only 77K original mileage. I checked the chain for stretch a couple of weeks ago and was astonished to find that it currently has 5 degrees of stretch. This measurment was taken using the factory procedure at 2mm of valve lift, not the old "line up the marks" approach. I'm really surprised at this amount of stretch since the car came with records indicating oil changes every 4-5K miles.

I did look up the factory recall on the 602 chains - it was in a Star issue a couple of years ago. As I recall it applied to early versions of the 602.962. My 91 model was NOT in the recall so I can say that maybe you should at least check the chain for stretch since it would appear that at least some examples of this engine DO seem to have chain stretch issues. I also agree with Sixto, I have heard (second and third hand) about some chain failures with 602 engines.

I'll be doing the chain in my car as soon as I can get the time.

Tim "

So I wouldn't put all too much faith that no cars except those covered by that TSB might experience such a problem!

My point was that these 602 engines in some cases have been known to exhibit timing chain problems, being that the original poster was looking for information about what could cause the noises he described it seemed prudent to mention the possibility of a timing chain issue.