Precision Raceworks Coolant Reservoir Cap | BMW B8 S4 3.0L SC V6 The threads are roll form

The threads are roll form tapped to create the toughest threads available and then stuffed with high-quality stainless ARP bolts to lock it all together

At the Soft setting

and a satisfying diverter valve blow-off noise

The IHI IS series turbos have been known to restrict oil flow under sporty driving conditions which can cause premature failure of the bearings resulting in broken turbine shafts

turbo outlet pipe

Precision Raceworks Coolant Reservoir Cap | BMW B8 S4 3.0L SC V6 The threads are roll formThe Precision Raceworks Engine Coolant Reservoir Cap is a functional and stunningly stylish way to add a nice touch to any engine bay! This cap come in three color options so there is always a color that will work for you! Black with Billet, Black with Blue, and the Stealth series (all black). Many people don't realize it but the OEM caps have a pressure release valve built into them. Often times aftermarket companies don't know this either or just