Motor Oil?

[Zchild]

Hey there gearheads and bimmer dreamers, I need to get some ground truth on a motor oil issue. After the last DIY ay Curry's I was speaking with one of their mechanic's and he was telling me about a Mobil 1 0W-40 motor oil recommended for bimmer engines that would free up a few horse power and increase gas mileage. I went for my last oil change at the Curry's Falls Church location and switched to the 0W-40 and over night my gas mileage went from around 450 miles a tank to around 550 plus miles a tank. I've done the basic proformance modifications such as CAI, Shark Injector and SuperSprint exhaust but the engine oil change has done the most in feul efficiency. However I was talking with my friend Mike Robinson at Sports & Imports and he was telling me that zero weight motor oil can cause leaks in high mileage engines. I just trying to run this to ground and find out if this is indeed a concern. I'm just over 227,500 on my 00 323i engine. Thanks in advance. Happy Motoring...

[Thoreau]

Mobile 1 0w-40, Red Line 5w-40, Amsoil 5w-40 are all great synthetics for bmw's. Mobil 1 is the easiest to get and it does the job right. The lower the W number the better. Less friction at ignition. The latter number is the thickness at high heat. Just don't go above 5w on bmw's. They don't like that.

[OwnedbyDuncan]

FWIW before I sold my 90325i with 237K I used Valvoline 20W50Racing.
Never had any problems or issues. I believe weight depends on when you enigne was manufactured. I used whatever my shop was using and 20W50 racing was what was used in the engine for 16years and approx 236K miles.

I currently use Mobil1 in my Element and if I had a late model BMW I would use Red Line.

Dave Apker

[jhm5]

mobil 1 0-40 is certainly acceptable for your car, but it is very hard for me to believe that you'd see a substantial increase in fuel economy from oil alone, unless you were running really heavy stuf before.
450 miles a tank to 550 miles a tank would be a huge improvement, but you need to use a more precise measurement over a longer period of time over similar driving, road and environmental conditions to accurately say what the mileage is.

[Biggins]

I'm a little surprised at your improvement too, but that's great!

I think if you ask 100 enthusiasts, they're going to give you at least 80 different recommendations on which oil to use and what they use.

I've used Amsoil 10w30, Castrol 5w40, and will likely continue using Amsoil 5w30. I used Mobil1 on other cars I've owned and didn't really care for it.

[Zchild]

mobil 1 0-40 is certainly acceptable for your car, but it is very hard for me to believe that you'd see a substantial increase in fuel economy from oil alone, unless you were running really heavy stuf before.
450 miles a tank to 550 miles a tank would be a huge improvement, but you need to use a more precise measurement over a longer period of time over similar driving, road and environmental conditions to accurately say what the mileage is.

I'm sorry if I gave the impression that the gain was from motor oil alone because that's far from the truth... The gains came from a combination of Shark Intake, Shark Injector, SuperSprint Exhaust and Mobil 1/0-W40. These combination of things increased my gas mileage from around 450 a tank to around 550 a tank. If I could just manage to keep my foot off the gas a little more I think I could get about 600 miles from a tank of petrol. Just my two and a half cents worth. Happy Motoring...