6.4 hemi - 0w40 #

These new engines are very sensitive to viscosity...

Back in the 90's the retired parts manager at our local Ford store bought a new Crown Vic for his wife and continued to use his regular 10w40 Motorcraft oil.

40,000 miles later the engine seized... city driving clogged up the oil passages and burned up the main bearings.

Ford spec was 5w30 as I recall. Warranty denied.

Be careful what you use.