Q: Water pump issue

Most people wouldn’t say yes, it needs to be replaced. But the truth is, there is a bit of an argument within the industry about this. Before I go to far into that, let’s make sure we are clear on the form of leak we have here. I’m assuming there isn’t any liquid, only a crystallized stain at the water pump weep hole. If there is any wet drips or evidence of stains that indicate antifreeze has been running wet, then I would say the water pump should be replaced. Look directly below the pump to see if there is any evidence of a larger leak. A water pump seal is a unique seal that under certain circumstances will seep coolant. This is what you see in the form of crystallized antifreeze.

From my perspective, at 40,700 miles, as long as there isn’t any wet antifreeze dripping or pooling anywhere, I wouldn’t worry about it. Water pump seals will often weep when they are in the process of cooling or warming. This is more prevalent in climates that experience extremes such as snow or desert summertime temperatures. Water pump seals are spring loaded devices that are designed to work within the varying pressures that are normal for a cooling system. When the environment is extreme, it pushes these seals to their limit. I’ve seen vehicles that actually leak on warm up or cool down, but not when cold or fully warm. It’s not very often and newer vehicles have better designed pump seals, but the inherent weakness is still an engineering challenge.

I draw the line at wet weep holes or dripping. Even then, this is often a manageable condition. Short of running coolant out the weep hole at a constant rate, no matter the temperature, keep track of your coolant level. A weeping hole is not much more than a couple of drops of coolant. You shouldn’t be able to detect any loss from such a small weep.

Another detail that is important, but I wouldn’t expect to see on a 40,000 mile vehicle, is particulates flowing through the cooling system. If you see any evidence of small particles in the cooling system, this can damage the water pump seal and create leaks. If this is the case, I recommend a complete flush of the cooling system. In which case the best way to flush a cooling system is by removing the water pump and thoroughly flushing water through the block with a water hose. But I have never seen a 40,000 mile Toyota have such a problem, so this is doubtful.

If you need assistance and want a professional to take a closer look, a certified mechanic from YourMechanic can visit your home or office to inspect the fluid leak.