Big End Bearing Failure

[stryker]

Having driven my 156 TS 2.0lt since new (1999) without any major problems (certainly no engine related ones) I was alarmed to note a mechanical knocking noise eminating from the engine bay 5 days after the 72K mile service. Having stopped the car and towed it to the local dealer (at their suggestion) I was informed that No. 3 big end bearing had failed and a replacement engine was now required. I am yet to inspect the damage so am unaware of the extent.

Being cautious the cam belt was replaced at 60k and the car has been serviced at the correct intervals by the same dealer since new.

The service manager suggests the problem can occur following an oil change (which suggests to me that this is a known problem) although has not elaborated as to why.

The dealer suggests the car has run with low oil to cause this failure however I have not had to add oil between services and their own computer records do not show any oil related problems at service intervals.

Now faced with a very expensive repair I am asking questions about how this could have occured and who is ultimately responsible. The last service some 120 miles earlier did not flag up any white metal swarf in the sump oil nor any problems so Im left with the feeling the problem started within the last 120 miles or the dealer has not serviced the engine with the best of care and attention.

Can anyone help me understand how this could happen to a "young, well cared for engine"? More worrying is the comment from the service manager regarding bearing failure after an oil change!!!! What is he not telling me?
Thanks
Tim

[stryker]

Having inspected the bearings and talked with the technician I note no bluing of the shells which would indicate a lack of lubrication. The remaining shells shown to me were in good condition. The technician advised No. 3 was the first shell in line to be fed oil and therefore was the one most likely to fail.

The problem appears to have been caused through the slippage of one shell beneath the other.

The dealer states that it is not normal (read manufacturers) practise to prime the oil system prior to restarting the engine after an oil change although they do fill the filter.

The service manager and technican cannot offer an explanation for the failure although we seem to agree that the engine has run with a good oil level.

Could the shells have slipped, given excessive load, at start-up prior to receiving good lubrication?

Tim