I had my water pump/timing belt replaced about 5 years ago at around
60K miles, my current OD is 95K. There's an issue with my 2nd water pump and it needs to be replaced. My mechanic says he needs to remove/ replace the timing belt too ($500+ total). The pump is in a convenient place/orientation and it seems like it should be easy to tension the existing belt (even a rope tied to the front frame near the radiator would probably work), remove the water pump, replace the water pump, without removing and replacing the timing belt. My mechanic says this can't be done. I find this hard to believe, is this true, or is trying this a bad idea?