I am approaching 90K on my ITR and asked Mike K what to service beyond the timing belt and water pump. He suggested that I replace the timing belt tensioner (TBT) as well. What exactly am I replacing? Is it the TBT bolt, the pulley, and the spring?

Also, does the water pump come with the o-ring that fits between the pump and the block?

 

Once you're in there it's easy to replace. Loosen the 14mm bolt, and put the new one on.
The new water pump comes with the gasket. When you said o-ring, I thought you meant the o-rings that go on the water pipe under the intake manifold.

 

Thanks Mike