I have been told about the rod bearing on the number seven rod not getting enough oil and finally going bad. How long does it take for this happen? My truck has 9,400 miles on it now and every since I changed the oil it has made a "bad bearing"sound from the bottom end. It does'nt sound anything like piston slap. I am running 0w-30 Amsoil synthetic.

 

I run the exact same oil and viscosity. I have almost 13k miles. When these things start up cold, they make a little bearing noise for a second or two before oil pressure builds back up.

I was watching a friend of mine dyno, and I mentioned this to the tuner, Willie Figueroa from Diablosport, whom has tuned countless Lightnings and Cobras, and he told me they all (Lightnings) make this noise upon start-up.

Another thing is, some oil filters have worse anti-drain back valves than others. That could also make the noise more pronounced.

In conclusion, with 10k miles on your truck, and synthetic oil, I wouldn't worry about a bearing going out anytime soon. There's no magic between one oil or another, if you are already running synthetic. Same goes for viscosity with synthetic. Mine makes the noise every day.

 

Well mine makes the sound when hot or cold.