With the fan removed you should be able to closely inspect the harmonic balancer (the rubber ring on the crankshaft pulley). If you see any cracks replace the harmonic balancer.
Keep in mind that the interval for spark plug replacement is 100,000 miles or 4 years (whichever comes first). If the plugs are left in longer they will be difficult to remove.
I would also recommend that you inspect your air filter and pollen filters (located behind the glove box.) The air filter should be replaced at 60K miles and the pollen filters replaced at the "B" service.
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles