Conrod bearings

Quick Links:  Examples of Rod Bearings   Changing Rod Bearings    

There is no doubt that the original design/material of the E46 M3 rod bearings were not up to the desired quality. In 6th month 2003 BMW introduced new rod bearings – and some cars before this date got replacement on the warranty. The newer bearings are better – but how much better is unknown to me.

Another aspect is that the S54 is a really high performance engine delivering 107 HP per liter and rotating up to 8.000 rpm. This is the absolute top end of engines of that time – and for that sake the top of even modern N/A engines. This has its price. However if you do not track the car or drive “wildly” and obey the proper warming up, the engine will last much longer that one should expect - provided oil changes every 10-12.000 km and the correct oil.

Personally I would change rod bearings every 100.000 km. If I bought a car not knowing if the rod bearings had been changed I would change the bearings if the car was from before 6th month 2003 no matter the mileage. If the car I bought was after 6th month 2003 and had a mileage over 100-120.000 km I would change the bearings – which is actually what I did.

Examples of rod bearings

Here are some examples of used rod bearings. One must be cautious to read too much into the examples regarding the mileage since the car owners often do not know if a previous owner had the bearings replaced.  

Not to pursue any fearmongering but here is a terrible example of bearings far overdue. The mileage is unknown, but I guess the owner must have been deaf.

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Changing Rod Bearings

Here is a good DIY video of change of rod bearings. Note that the bearings being replaced had driven 154.000 miles – quite a bit.
The video is from FCP Euro: BMW S54 Rod Bearing Replacement DIY (2001-2006 BMW E46 M3):

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