I have 98 dodge avenger had the water pump seize on timing belt and busted 8 vavles on the head in dec. the head has been rebuilt new water pump new timing belt new thermostat and housing as well as radiator hoses. My car is overheating and boilling in the overflow. What else could be wrong?

If you're needing to change the water pump, yes the balancer has to be removed. The timing belt turns the water pump. You say you're not a mechanic, because of removing the timing belt, hire a mechanic to do this job.

if you changed the valves and replaced the timing chain/belt you need to put the engine at top dead center at the number one cylinder

This does sound like your water pump is leaking, or your head gasket has busted on the outside edge. I would check the water pump first, as it is fairly common for the seal to bust and leak coolant from the water pump.

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head gaskts are gone please repace them

Why did you change the head gasket Patrick,
Was the engine missing before you did this,or did you over heat the engine from low coolant?
If the miss was there before you may have burnt a valve,

The pump is driven by the timing belt so you basically need to take the front of the motor apart. It is quite a job to get at it but is doable. If you are going to do the job I'd suggest changing the timing belt, tensioner pulleys and the cam and crankshaft seals as well, may as well do some preventative maintenance while it is apart. I've got the whole proceedure and will make u a copy if you want.

If this is 2.0 liter duel over head cam than engine damage most likely will happen if the timing belt brakes sorry about the bad news .

replace radiator cap system depends on good pressure to keep from overheating

depending if its a 2.0 or a 2.5 really either or, i personally recommend taking it to a shop, you have to pull the motor to get to the timing belt on a 2.0 and just the same on a 2.5, that or tilt it on such an agle to access the timing belt and to be able to remove the proper bolts to access the belt, then after you get to the belt you have to have a special tool for the belt tentioner and align the top dead center with the new belt, in doing this you may have to have a camsaft turn in a way that when the tentioner is let off they all align with the new belt... it is a very agrivating process...

Your timing belt jumped. Need to have belt replace and timing reset with timing jumped hope no engine damage