Well, after being a thin oil advocate forever, and sticking by 5w-20 for the 3V 5.4 in my F250, I now believe that 5w-20 is not ideal for my engine. I understand these engines to be very "tolerance" dependent, and some engines have different bad or stacked tolerances that produce different symptoms. These engines have a wide range of defects ranging from timing chain tensioners, guides, VCT solenoids, Cam phasers, improper spark plug torque, injectors, exhaust manifolds and cam followers. The range of possible issues make tracking down noises infuriating. I ran my truck yesterday below 20 degrees. I think the added viscosity from the cold weather made the oil unusually thick (Supertech 5w-20 dino). For the first time, there was no ticking. I bought seven quarts of Supertech 10w-40, and I am going to give it a test run when the snow melts. I may just roll with that OASIS message recommending 10w-40 for 5.4 3Vs that tick if that does the trick. Not ripping on these engines- a company I worked for had a fleet of about 8 F250/150 with this engine with 100K+ miles on some of them used as service trucks with highly indifferent maintenance, and they were absolutely fine, no noises, ran great. However, I have heard two ticking 5.4s, it is annoying. Anyway- I am admitting defeat on 5w-20 for 3V Ford V8s. After seeing data on VCT operation, I believe heavier oil is fine, and possibly even the way to go.
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