...higher year...? Ive herd that people who use the synthetic Blend are having problems with there motor( something with there valve phases or something) ,, Ive herd that synthetic oil will stay towards the front of the truck because Ford redesigned there f 150 models so that the engine is actually higher/ tilted higher causing synthetic oil to stay towards the front of the vehicle. I herd this info from a mechanic where I live ,,, Yet in my owners manual It says to use the synthetic blend..? /... Anyone have any advise?? I have a Ford f150 5.4 triton engine,should I use a synthetic blend or not?? thx