I believe the Ford 5.4l 3v really is designed for 5w-20 after reading the article link below.
I would also note that Ford's new 5.4l 3v operates with a 15 degree cooler thermostat temperature than previous model years (2004 and earlier). Older engines had a 5 quart capacity, while the newer engines are 7 quarts. Both of these changes are done to dissipate the extra heat off the higher flow/volume rate of the 5w20 oil. I found the main bearing design reference interesting since they are a different shape and reduce oil bleed off. It also mentions that main/rod bearings specs are different for the VCT to function properly.
http://www.hotrod.com/techarticles/engine/hrdp_0908_variable_valve_timing/ford_modular_v8.html
I would also note that Ford's new 5.4l 3v operates with a 15 degree cooler thermostat temperature than previous model years (2004 and earlier). Older engines had a 5 quart capacity, while the newer engines are 7 quarts. Both of these changes are done to dissipate the extra heat off the higher flow/volume rate of the 5w20 oil. I found the main bearing design reference interesting since they are a different shape and reduce oil bleed off. It also mentions that main/rod bearings specs are different for the VCT to function properly.
http://www.hotrod.com/techarticles/engine/hrdp_0908_variable_valve_timing/ford_modular_v8.html
Last edited: