What happens when a water pump fails? Welcome to Mercie J Auto Care, where compassion and craftsmanship come together. I'm Rick Smith, master certified technician. Now the primary responsibility of a water pump is it circulates coolant or antifreeze or radiator fluid through the engine, through the radiator and also circulating through the heater core, which is how you get heat inside the car. Now a water pump can quit pumping, mechanical water pumps typically don’t do that, they do on occasion but not very often and Electrical water pumps may also do that. Most often what we see when a water pump fails is that the water pump leaks. So in either case, we are not circulating that coolant through the engine properly. Either it leaks so we don’t have enough coolant in there and it doesn’t cool the engine or if it stops circulating it doesn’t bring it out by the radiator and cooling down so the bottom line is when we have a problem with the water pump. It’s going to cause the engine to run too hot and we definitely don’t want to overheat the engine and cause damage. If you have a water pump problem I recommend you don’t drive the car you get it towed to the shop and get it resolved so that you don’t inadvertently damage your engine by driving the car. I hope this answers your question until next time, safe travels and blessings to you.