Re: BMW is the 2.5 I6(198 hp) or 3.0 I6 (225 hp)or 3.2 I6(240 hp) better, more reliab
There are several models of the 2.5 and 3.0 L I6's. The from the early 90's to 2006 they were the M50, M52, M54 and N54. They were all pretty reliable. The cooling system is a weak point and they were likely to warp the head if overheated. The 240 HP 3.2 would be an S52 from an M3. More power, more maintenance and more expensive. There was no 198 HP 2.5 L I6, though the M50 version, which was built from 1990-1996 was rated at 189 HP.
The biggest performance difference between the 2.5L and 3.0L engines is the significant increase in torque. I had the M50 in my 1992 325 IS which I drove for 15 years. My 2004 330Ci has the M54. They have both been reliable.
