____ Hello,
Oil pump chain in my 1981 300SD 617.951 engine (267,000 km) failed early this summer. Failure was most probably due to severely worn pump chain tensioner (plastic part). High resolution images of the failed parts can be viewed at http://24.108.159.23/misc/mercedes/. Q??: How many of the group's readers have seen this failure or have heard of it?
Because cylinder #1 big end bearing looked ok, garage mechanic replaced oil pump, pump chain, tensioner, timing chain, guide and tensioner. After 1,000 km cylinder #1 bearing failed. Conclusion: oil pump failure most likely causes bearing related failures, necessitating engine overhaul.
Q??: Does the group concur with above conclusion?
Current status: Failed engine sitting in workshop ready for tear down and detection of further failures this winter. Replaced failed engine with locally available 617.952 type (from wrecked W123 wagon). Blanked off hydraulic pump drive. Runs well, good power, no smoke, fuel consumption is 12.7 km/l (35.9 miles/IMPG = 29.9 miles/USG) in mixed highway/city driving.