Hello,

This is my first post so please bear with me.

My 01 Century "the BU" sprung a leak in the cooling system. Being the proactive guy I am I went ahead and replaced the intake manifold gasket, water pump, thermostat, spark plugs. Got it all put back together, no vacuum leaks. However, still leaking coolant from passenger rear motor. Determined timing chain cover gasket is culprit. So i bought a OEM gasket set from auto zone. So far I have alternator, power steering, and water pump off and out of the way.

The question is: A-Do I have to remove the belt tensioner to remove the timing chain cover. B- Do I have to remove the lower pulley and if so does it require a puller? I am aware that I need to mark the lower pulley to the cover so I dont screw the timing up. C- I have heard that a "non-hardening permatex silicone sealer works best, what exactly needs sealed after the new gasket goes on?

Many thanks to anyone who can provide some wisdom!

My experience is from a 1994 Buick LeSaber so it may differ some. You will have to pull the vibration damper/harmonic balancer/crankshaft pulley from the front of the timing cover. There is a flexible piece in the passenger side fender that will enable this removal.
I had a very difficult time with the bolt in the vib.damp/harm.bal./crank. pulley I had to use an air wrench and even then it did not want to come out. Once the boltis out you will need a steering wheel/gear puller with fine pitch 1/4 X28 pitch bolts to get the pully off.
I also had to remove the passenger side motor mount AKA Torque Axis Mount. There are lots of comments on this on this site. I used a couple of nuts to make a jamnut to remove the stud on the engine block side of the Torque Axis Mount. One other writer suggested replacing this with a bolt which is a great idea since it is a total pain to get it out. Raising the engine with a jack after the ALL of the bolts of the Torque Axis mount are out was really helpful. I raised mine about a 1/2 -1 inch made all of the difference. You don't need to mark the pulley it only goes on one way. I did not have to take the belt tensioner off but I don't about yours. You don't sound like you have a lot of experience with cars or you would know about RTV silicone rubber sealants. With all due respect this repair is, IMHO, a difficult, challenging job for a pro let alone an amateur. There I have covered some of these problems not all of them do I have a good answer for.