Connecting rod bearing failure BMW M5



I had two connecting rod bearings fail at 60,000mi.The BMW service told me I needed a new engine ($24,000)which I declined but did replace all con rod bearings. Now VANOS is not functioning correctly and they tell me it is due to bearing fragments getting into the VANOS (variable valve system). Doesn’t the oil filter remove particles before they can get to the VANOS? They refuse to correct the VANOS. They say that they told me to replace the engine and therefore it is my fault.


What is the model year of your BMW?

Is this vehicle still under the Power Train Warranty?

Did you use the type of oil specified by BMW and did you change it according to their schedule?


2001 E39 series M5.
Warranty is over.
Only serviced by BMW on schedule.
What do you think about this bearing (2) destroying this engine?


Did the oil level get down so low that the oil psi light came on? That is the usual cause of rod bearing failure. Are we getting the full story?


Cars are all disposable consumer products. The only thing that matters is cost-per-mile. VANOS is a sales tool used to sucker techies into spending twice as much for a car than they should. Now, with this repair history, your car is little more than salvage. If you can’t afford these toys, don’t buy them. The KISS principal has served consumers, especially automotive consumers, well for many years. Cancel your subscription to Motor Trend and Road & Track and buy a Celica…


As per the usual, there is a LOT of missing info.
BMW said you need a new engine, but you did replace all rod bearings. Who replaced them?

Was the crankshaft reground or replaced? If not, morons at work.

Was this one of those drop the oil pan, throw in a set of bearings, and pray to the gods that everything will be ok?

The oil filter will not stop all metallic particles on any engine. A % always recirculates.

There’s always the possibility of a fluke assembly line failure but the chance of this is near zero. Rod bearing failures are caused by:
Overrevving and/or hard driving.
Lack of regular oil changes.
Running the oil level low, or completely empty if someone left a drain plug loose, etc.

Did you replace these bearings yourself or have another shop do it and now you’re going back to BMW complaining of engine problems?

If the BMW dealer told you that you needed a new engine and if you insisted on the BMW dealer ONLY installing a set of bearings then yes, this is all your fault. The original problem was more than likely your fault.


Caddyman do you realize that a Celica also has VANOS which is just BMW’s name for variable valve timing. Its not a complex automotive technology and its been around for 20 years.

To the OP have you tried an independent qualified BMW mechanic for a 2nd opinion?



I agree that you need to forget about the dealer (they are not going to pay for anything if you didn’t follow their advice) and find a good independent bmw shop. Have them diagnose the problem with the valve system and find out what it will take to fix it correctly, they may also recommend a replacement engine. I am also surprised that you had a bearing failure at 60K miles (on any modern car), what caused the original bearing failure?


Just dredging this up to see if the OP is going to add any real information to their complaint.

It’s impossible to guess at a rod bearing failure without details, but almost every bearing failure is owner inflicted and involves oil, or the lack thereof.
Obviously there was some knocking and oil light flashing going on and one wonders when, or if, the oil level was ever checked.
“Serviced by BMW” does not say much.

I’m also curious about the details behind this “bearings only” repair.


So not to stop the flow of oil through the engine. There is a internal bypass in the oil filter that opens if the oil pressure gets so high from a restricted/clogged filter. In your case this was highly probable, allowing the metal shaving to circulate through the engine unabated.