[code7rpd]

I've been following a number of threads on the S65 rod bearing issue and bought an e90 about 2 months ago with 70k on the clock. It had the standard BMW oil changes as part of the included maintenance and while the car seemed to be in great condition, I got concerned over rod bearing wear and decided to get them replaced - a big thanks to the board for all of the information on this potential failure point. As you can see from the photographs they were in bad shape and I'm glad I got them replaced. Unfortunately, I didn't do UOA as the oil was changed when I bought it and had done about 200 miles since the change, so it didn't see like it would have been too helpful.

After reading many threads about the how and why these bearings are failing far sooner than they should I decided that considering this is a weekend car that sees some spirited driving and no track time, it would be best to run Mobil 1 0W-40 rather than the TWS; the weather isn't too extreme in Northern California and gets down to the 30's in winter and up to 100 in summer inland.

I had everything replaced with the newer 702/703 bearings and factory rod bolts. In the event anyone is interested in the oil pressure with the 0W-40 versus the 10w-60 I listed them below. I put a set of Defi Racer gauges in the car and even before changing from the TWS to Mobil 1 I noticed something odd with the pressure. If I floor the throttle when driving or blip it when it neutral the pressure drops by about 5-10 psi and quickly rebounds climbing upwards. I'm not sure if this is because the vanos is running off the main oil pump or not, but I've never seen it happen on any other car - when the bearings were replaced the oil pump and associated pieces looked fine, so I don't know if this is normal or not. I mean't to ask the shop that did the work, but didn't get around to doing so - if anyone has any insight on why this is happening, please let me know. Here are the pressure readings:

Castrol TWS 10W-60:

Oil Temp Ambient Temp Idle 2k RPM 3k RPM @ 6k RPM

Cold 82 F 94-96 PSI
165 F 82 F 55 PSI
210 F 82 F 43 PSI 72 PSI 82 PSI 90 PSI

Mobil 1 0w-40:

Oil Temp Ambient Temp Idle 2k RPM 3k RPM @ 6k RPM

Cold 72 F 70 PSI
165 F 72 F 48 PSI
210 F 72 F 33 PSI 64 PSI 78 PSI 80 PSI

I hope this adds to the thread and if anyone has any insight on the fluctuating oil pressure, please let me know your thoughts - it was occurring with both oils and the car runs and sounds fine. I haven't put enough miles on it to see if it is burning any oil, but will report back. Thanks.