FAQ #1: Hole between the oil drain flange and coolant port a product defect? ANSWER: NO, the hole between the oil drain flange and coolant port is not a product defect and does not impact the structural integrity of the CHRA. The hole is NOT perfectly round and measures 3 to 4 mm in diameter. During the CHRA machining process, the oil drain flange is tapped with the proper thread pattern and at the leading edge of the threads, the holes are designed to "break through" the casting at various points. The "hole" is one of the points where the casting is designed to break through. Typically, it will break "all the way" through which makes it look less like a "hole". But because there is extra material that remains around the tip of the machined area, it looks like a hole. That hole is "external" to the CHRA and has absolutely no bearing on the structural integrity or the internal operation of the CHRA itself.

So, regarding this hole... you have absolutely nothing to worry about!