Is there a rule of thumb for replacing a water pump? I changed mine like 5 years ago and it still looks good. Nothing in the weep hole and temps seem ok, but since cooling kills a rotary fast, I was wondering how long this will last and whens the best time recommended you should replace it to avoid failure? kinda of a newbish question.

 

I don't know that there is any predetermined or best time to replace it. I would leave it alone until it starts to leak from the weep hole and replace it at that point.

 

Waterpump shoudl be fine until you get it leaking through the hole on it.

More important things woudl be thermostat,radiator,ducting,and flushing coolant every once in a while to get rid of possible minerals.

 

Speaking of minerals I always use distilled water in mine when I mix up my water/anti-freeze mixture.

 

I had one new Mazda replacement water pump that died after about 4 months use.

 

Yeah, it all depends. There are some that fail fast, while there a probably some people withi the original. I think the saying "don't fix what ain't broke" applies here.