Been reading numerous threads on ticking sounds and engine "clatter." Sometimes at startup for about 10 to 15 seconds, sometimes longer. Some say it never goes away. Then you read about how some feel it's the filters' vault. Bad ADBV or just a bad filter period. My question: I have a 01 F150 5.4 with M1 5W-30 and Motorcraft Fl820-S. When it's below, say 35F and a cold engine, I get a slight knocking sound for about 10 seconds, then goes away. When the temperatures are above, say 50F and cold engine, no noise at all. Is it the oil, oil filter or engine itself? Is this cold knock? Piston slap? I've heard other members say piston slap will go away after engine has warmed up, others say it never goes away. Could the filter be bad? I mean that difference in temperature shouldn't even matter with the M1, right? So, what is it? Bad ADBV? Bad oil pump? Aluminum heads that just make noise that us older ( I'm only 40) iron block guys are not used too? See what I mean? LOTS of potential explanations out there....so what does one do besides worrying????