https://ssnperformance.com/4-e....xhaust-muffler-pipe-
However, it’s not actually oil, but diesel fuel that has mixed in with the oil. One of the more infamous problems on the 6.4 Powerstroke is its weak pistons that were prone to early cracking. A cracked piston allows extra air into the cylinder, which then decreases the compression ratio. The high-pressure fuel pump was also a good part that had 20% more flow than its rivals at the time and more than its successor in the 6.7 Powerstroke. Though we’ve already established that cra