I am considering purchasing a 2001 BMW 325i. It has a 2.5 liter L6 engine with 109,000 miles on it. If I do buy it, the first thing I am going to do is start an arx cycle on it. My only concern is that BMW states in several different places on the car that you should only use BMW spec oil and they recomend Castrol Synthetic. Do you guys think running it on dino or even a group 3 synthetic would hurt this engine?
Hotrod 4x4. Don't worry. I'm on a cleaning cycle right now on my 2000 328i. I'm using Kendall GT1 Synthetic 5w40 which is a grp 3 oil. For my rinse phase, I will use Shell Rotella 15w40. You don't have to use the BMW oil. I've got a supply of Castrol Syntec 0w30 and Valvoline Synthetic high mileage 5w30. Both are BMW LL-98/01 approved oil. For your cleaning phase, use a grp 2/3 5w40/15w40 oil. Regular North American 5w30/10w30 is not A3 rated. For the rinse phase, do not use a synthetic or high mileage oil. Use regular mineral oil in the 40 weight. This is for any Euro (BMW, MB, VW etc.)car. Any other car, use any 5w/10w30 mineral oil.
I'm in the same boat guys. I just picked up a 95 BMW 325is with 164.5K miles on it. I plan on running 2 cycles of auto rx (clean/rinse). I have 3 bottles of ARX on the way. Problem is, the user manual is so vague on the weight of oil to use I am confused. I'm not sure what is in there right now. I think it is M1 in a 30 weight. The oil was just changed before the purchase. Can I use this oil to clean or is it better to put in a group 3 oil like castrol? If so, what weight? Most BMW sites sell mostly 40 weight oils. With summer coming, how 'bout a clean cycle with Castrol 5/40 and rinsing with Castrol GTX in 10/40? After both cycles, run synthetic or go all dino? What do you think?
The car runs well now and I can't wait to see what auto rx can do to clean it up a little bit. It did a great job on my Expedition and Acura TL.
You will get the maximum benefit of ARX by using dino in all phases. However since you are going to run 2 cycles and the oil is practically new just start off with what's in there now.
For a little information on what weight is right for your engine check out this article on motor oil: http://ferrarichat.com/forum/faq.php?faq=haas_articles#faq_motor_oil_basics