I have a ticking sound coming from the drivers side. I cannot diagnose whether it is coming from the valve area, or exhaust area. I know that cam oilers are a common problem, but i dont think the sound is coming from my valve area, and the tick gets faster with accelleration, while cam oilers cause a constant tick, correct??

I have to change my power steering rack out, which is getting taken care of, and I got an oil change and switched from regular oil to synthetic.THE TICKING DID NOT START UNTIL I SWITCHED TO SYNTHETIC OIL, LITERALLY A FEW HOURS AFTER. It comes and goes, it usually stops after a a few minutes of driving.

When the ticking sound is present it gets faster with accelleration. Could switching to synthetic cause this sound? Should i switch back?? What is the recommended oil for a 1997 E420? If anyone can answer my questions i would greatly appreciate it. Thanks