?Thinnest oil possible always best?

[Yuk]

Why hasn't Dr. Haas chimed in here? I would think this topic would be right up his alley.

 

[ChiTDI]

Had a '95 and had the exact symptoms until the Motorcraft FL-400S was used. 5w30 winter and 10w30 other seasons. Didn't matter brand of oil, but would faithfully knock with different filter.

 

[FZ1]

Agree. Thinnest runs cooler.