Fall Line Motorsports BMW M3/M4 Oil Cooler Guard (G80/G81/G82/G83)Fall Line Motorsports BMW M3 M4 Oil Cooler Guard. Unfortunately, the S58 engines oil cooler precariously exposed with no protection. A direct impact to the oil cooler can have catastrophic effects, draining the S58 of all of its oil in seconds, a fact that more than a handful previous generation M3 and M4 owners have had to learn in a painfully direct way. Having seen that this was a critical need for the M3 and M4 cars, IND worked with Fall Line