Quote:
Originally Posted by pitos_7
I use Royal Purple HPS 5W-30, I drive a 325i though (N52 engine), but this oil should suit your N54 engine as well.
After switching to Royal Purple, engine runs butter-smooth  Can't hear any valve or cam or lifters noise at all. The engine runs significantly quieter, it purrs like a kitten when it's idling in traffic lights. RPM needle seems to rev a bit more freely as well
I don't have an oil temperature gauge on my car, but other 335i owners on this forums claim lower temperatures using Royal Purple.
Royal Purple HPS is expensive though, $92 for a 5L bottle off eBay.
http://www.ebay.com.au/itm/321612459...%3AMEBIDX%3AIT
Not many people would want to put that kind of money in an engine oil, but being a car enthusiast I don't mind obviously. I've used this oil on my Honda Civic, VW Jetta 2.0 FSI Turbo (same engine as a MK5 Golf GTI) and lately used it in my 325i and all three cars ran much quieter and smoother so it's definitely not placebo.
Join a forum called BITOG "Bob Is The Oil Guy", all what they talk about there is engine oil. Over there, we love Royal Purple and Redline (used oil analysis results proved these two provide the best wear protection). Sadly though, we don't get Redline in Australia. So, I stick with Royal Purple 
Mobil 1 0W-40 in the gold bottle is not a fully synthetic oil (regardless of what is written on the bottle), I think it's group III. While Royal Purple and Castrol LL-01 are Group IV/V. The old Mobil 1 Formula from the nineties and early 2000's used to be fully synthetic but not any more.
Two things to remember if you put Royal purple in your car:
1- Do 10,000kms oil changes as Royal Purple doesn't have BMW's longlife certifications that Castrol has and won't last 25,000km in your engine.
2- Royal Purple is officially not on BMW's recommended list of oils to use for BMW cars. But you gotta realise that part of this is marketing as well. Castrol paid BMW millions to only recommend Castrol and to stick that Castrol badge on our engine oil lids. In mid 2015 BMW is going to switch to SHELL and all the OEM oils that BMW dealers will be stocking will be SHELL brand only! (The guy working at Doncaster BMW parts department told me this last week). 
Other oils to consider:
1- Motul 8100
2- German Castrol (buy off eBay, not available in stores in Australia. Comes in green bottle I think)
3- BMW LL-01 OEM oil from the dealer
4- Liqui-Moly is pretty good too |
Redline is available in Australia, it just isn't promoted much at all.
As for the Mobil 1 not being a true synthetic, I'm unsure where you have that info from? Mobil 1 is a true synthetic, and its the castrol edge which is produced from a 'inferior' group III. Mobil 1 actually filed a lawsuit in the usa against Castrol in the late 90's in the USA for this (castrol won the case)
Being 'synthetic' is a bit of a loose term, and I believe that's why castrol managed to win the case!
The only 'true' synthetic castrol is the black bottle made in germany syntec (I've never seen it for sale here in Australia)
Yup I totally agree about the whole bmw approved oil scheme. It's surprising that BMW have finally changed their oem supplier to shell (it's been a rumour for quite some time now!)
Mobil 1 0W40 in my opinion is definately a superior oil over the castrol edge 5W30, unfortunately it's much more expensive to purchase here in Australia (I bought some from Walmart back when the ozzy dollar was equal for close to $25 for 5 quarts and it cost about that again to ship it here for some friends)