Castrol and BMW had established a partnership around 2000, when the E46 M3 was introduced. One of the things Castrol brought to the partnership was their 10w-60 oil, which had been developed in racing. They were planning to cooperate with BMW to adapt that oil for M cars.
Then, M3s started having rod bearing issues, so BMW introduced a number of changes to the engine. That's when they took the opportunity to switch from BMW's 5w-30 synthetic (also custom-made by Castrol) to the new 10w-60 oil.
By that time, Castrol and BMW had developed the 10w-60 into a specialty product; Castrol tweaked it for BMW, and BMW designed its M engines with that oil in mind. That's why later M cars with high-revving (>8,000 RPM) engines started requiring the 10w-60 as
One of the biggest problems I've seen with the S54, and this is from a local BMW performance shop thats torn down a now significant number of used engines that dyno'd and compression/leakdown tested poorly, is that these M engines, ALL of them, need to be warmed sufficiently before being driven hard. These engines should NOT be daily driven engines, to the store and back, short-trip driving, etc. They're designed for the open road, and the track, to sustain high-load, high-temp use.
My S54 has a redline short of 8000RPM and warm up procedures were always followed. Using TWS and had to change Rod bearings at 60,000 miles of normal ( not track day ) driving.
Think I would have done better on 5W-30? Should I use it now?
What year S54 did you have by chance? Early cars were going to fail no matter what. I've heard a few claims, from fuel dilution (all S54 cars that got bearing recalls had their PCM's reprogrammed at the same time), to wrong oil, to improper bearing specs or manufacturer processes for the bearings themselves.
Originally Posted By: d00df00d
"Normal driving" is one of the worst things you can do with an S54, no matter how gently you warm it up.
If you're not going to drive it as it was meant to be driven, switching to a BMW-approved 5w-30 might help.
Again, make sure it meets the right specs per BMW. Don't just pick up any synthetic 5w-30 and expect it to work -- most won't.
This. Get them up to temp (oil temp) and beat the [censored] out of them. It's what they were built for. It probably WOULD run better if you tracked it.