In my neck of the woods, 5 years on an oil maintained residential pump is a short lifespan. While there are some tricks for reducing the noice, you might as well change it or at least have a spare pump on hand for that inconvinient holiday breakdown.
It sounds like you should also consider flushing out your system when you do change the pump.
It sounds like you should also consider flushing out your system when you do change the pump.