Some Ford Expedition owners report experiencing issues with the oil pump, roller followers, cam phasers, and tensioners. Many have noted that cam phaser problems often begin with a failing timing chain tensioner seal, which can lead to slack in the timing chain, damaging plastic guides and potentially dropping debris into the oil pan. Additionally, owners replacing cam phasers on Triton engines are advised to also replace the oil pump, timing chain assembly, roller followers, and water pump, especially if the vehicle has over 140,000 miles. Some owners have found that using metal tensioners from older models (1997-2003) can help prevent problems with plastic chain guides breaking and obstructing the oil pickup tube screen. For those needing a timing job, costs can reach around $2,000 for genuine Ford parts, including lash adjusters and roller followers. It is also crucial for owners to inspect cam and roller followers for wear, as worn lobes may indicate further issues. If cam phaser noise is experienced on startup, it is recommended to consult with a dealer, as there may be relevant notices or warranties regarding this problem. Addressing these issues is vital for the proper functioning and longevity of the Ford Expedition's engine.