Front pulley bolt size?
 

Hi I can't seem to figure out the size of the pulley bolts. The four bolts that retains the actually pulley to the hub? Trying to find replacements. Are they the same size as the oil pan bolts?

Also, does anyone know where I can find the o ring for the oil level sensor? Do I really need to replace this o ring or just put a bead of silicone and reinstall?

Not quite sure on the dimensions, I just replaced all of mine, I took one to the hardware store and just matched the threads.