Cloud9...68

My car has been losing coolant for a little while, and investigation didn't turn up any of the usual suspects (leaking hoses at their connections primarily, based on past experience), and I saw signs of coolant on the front of the engine, so I bit the bullet and removed the belts to get a closer look at the wafer pump. It definitely looks like the pump is the source of the leak, and given that my records show it was last replaced in 2008, I've definitely gotten my money's worth out of it, so I have zero hesitation about replacing it.


Leaking water pump(?)

But before I pull it out, I just wanted to ask the experts on this forum if it's possible that the leak could possibly be something else. The pump's shaft has zero play. I'm wondering what might be the mechanism for it to leak at the mating surface to the block. Could it have warped over time? I just want to make sure I have my bases covered to avoid missing something and causing me to do this big job over. Thanks.

931guru

Replace it. You will need to do it sooner or later, get the experience now.

Cloud9...68

Yes, I will definitely replace the water pump. I just want to be as sure as I can that there isn't another possible cause of the leak, to avoid having to do this job over. I guess once I have the water pump off, I will be able to get a better look for any alternative or additional causes of the leak. I will also replace the belts, since they're a couple years old.

jsheiry

The plastic heater valve behind/side of cam cover is a known ticking time bomb especially if aftermarket and close enough to water pump area that a leak from it could dribble over to water pump and perhaps confuse the issue.

shinrai

This. Be sure to do this. Get new clamps.
Also do the water pump and thermostat. Easy job.

Cloud9...68

Thanks - I replaced the plastic heater valve with a metal one years ago, so it should be OK, but I will inspect it closely. These are exactly the kinds of inputs I was looking for - hopefully it's "just" the pump, and not some more subtle, hidden issue, because leaks can be tricky to troubleshoot.

Cloud9...68

OK, the water pump is off:


Leak shown with water pump removed

I was surprised to find the gasket in excellent condition - almost like new. I was expecting to spend an hour scraping its remnants from the block, but it came right off attached to the pump. The nuts and bolts for the pump were all nice and snug, and all threads appear to be in good condition. So I guess the main thing that could have caused the leak would be the mating surface of the pump being warped. Is this a common problem? In any event, hopefully the new pump will eliminate the leak.

Gage

Check if any of the waterpump bolt holes go through to the water jacket. If so, they will require a thread sealant.

oppositelock

If not too late, get replacement fasteners in stainless steel. Makes future jobs much easier. None go through a water jacket.