Does anyone know if it is OK to switch from Castrol synthetic to Mobil 1 in an M4? I'd never thought about changing oils, but now BMW is now partnering with Shell instead of Castrol. I assume the M3/4 (or any BMW up to this point) has been engineered and developed using Castrol synthetic oil/lubricants, but does it matter? I don't know that either product is actually 'better' than the other, I've always used Mobil 1 based on manufacturer recs (Porsche). Do only the SAE specifications matter in regards to choice of oils? Thanks for any input and Happy New Year!
This thread, the poster includes a picture from his engine manual - http://www.bimmerfest.com/forums/showthread.php?t=792754 Most of the rest of the thread is off topic, but if that picture is the same as your manual, it mentions the recommended oil specifications - recommended: 0W30 alternate: 5W30 approved oll types: ACEA: A3/B4 API: SK/CF or superior grade Off the Mobil 1 website, it looks like the 0W30 choices are Mobil 1 Advanced Fuel Economy & ESP X1 - Looking at the Advanced Fuel Economy: https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-advanced-fuel-economy#0W-30 Mobil 1 0W-30 Advanced Fuel Economy synthetic oil meets or exceeds the requirements of: ACEA A1/B1, A5/B5 API SN, SM, SL, SJ ILSAC GF-5 Ford WSS-M2C946-A Ford WSS-M2C929-A According to ExxonMobil, Mobil 1 0W-30 Advanced Fuel Economy is of the following quality level: General Motors GM 4718M General Motors GM 6094M API CF I'm not an oil engineer, but presumably you can google up exactly what the ACEA specs mean - if A1/B1, A5,B5 exceeds A3/B4, then that part would be ok, presumably. The Mobil 1 statement at the bottom says it's of the quality level of API CF, but above it says meets or exceeds API SN, SM, SL, SJ; I'd think it would be better or more confidence inspiring if it said it meets/exceeds API CF than the seemingly less-specific statement at the bottom. The EXP X1, in 0W30 & 5W30, it says ACEA C2/C3 for both, but only the 5W30 says "According to ExxonMobil, Mobil 1 ESP Formula 5W-30 is of the following quality level: API CF" Searching the 5W30's - Extended Performance: API SN, SM, SL, SJ; ACEA A1/B1; Extended Performance 5W-30 is of the following quality level: API CF High Mileage:ACEA A1/B1, A5/B5;API SL; Mobil 1 High Mileage 5W-30 is of the following quality level: API CF Mobil 1:ACEA A1/B1, A5/B5; API SN, SM, SL, SJ - notably, it does NOT say anything about API CF Super Synthetic lists only API SN, SM, SL, SJ, no ACEA specs shown, or mention of API CF Best I can tell, it doesn't look like any Mobil 1 oils mention the same specs as in the M4 manual, so the conservative answer would be no - if you can confirm what the specs mean, than you'll know for sure. Ideally, it seems you'd want the oil bottle to say the same as in the car's manual. With any luck, the switch to Shell might mean an approved oil but at lower cost to owners.
I say for reasons mentioned above and the castor BMW blend was specifically made for BMW engines so if you can I would stick with oil designed for your engine especially with a S motor like yours.
A belated thanks for the reply! I knew a little about viscosity, weather-related requirements and some of the specifications, but I'd never really looked at it this closely. You schooled me, Thanks!
