There may be some validity to the argument supporting mb reducing parts quality over time, including the w124.
My 87 wagon has the original water pump with 285k miles no complaints
the 94 E320 has a new to the car water pump (MB part) and it is already making bearing noises. Now this is the 2nd water pump in a total of 85K miles on a dealer serviced and proper coolant w124. The belt seems tensioned correctly and rolls smoothly with no wobble but 2 factory pumps in 87K miles seems poor quality.

I have also noticed that the E320 while being a garage queen most of it's life has more signs of surface chassis and body rust than the 87 w124 that has been sitting outside in the elements for most of it's life. While the fixtures and grade of steel used in manufacturing both series may have been the same, I think that the bean counters started skimping on things like rust-proofing and parts quality requirements as the series matured. Time will tell.

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)