How to spot a water pump failure-with pics

Most people report no failure until theyre in the shop for something else- and the dealers tells them its leaking.

Others- will leak for a while- and suddenly fail. Some leak- and are pressure tested and pass- only to fail a while later.

In my case- it was pretty quick.
Mileage- 39,400.

From one of the pics above its possible it has leaked for a few days.
But it cant be more than a week old. I checked it (visually) last week- yup- I get down and look at that area often.
I drove the vehicle about 100 miles yesterday- and there was no coolant on the driveway. I also smelled nothing.

Today I visited my sister- and strangely- we HEARD the failure. It sounded like bad bearings. Like an alternator going bad(if anyone is familiar with that sound). It lasted for about 30 seconds- went away- and then came back....
At that point I popped the hood- and looked under the car- to see the 2 round signs of coolant- oily looking spots (at 1st I thought- PS pump?).
The noise then went away. I drove home about 2 miles and took the pics above.
The coolant reservoir was at the FULL mark.

Complaint- Cooling Concern, Customer states vehicle leaking coolant.
Cause- Vehicle leaking coolant, Pressure test cooling system. Found water pump leaking.
Correction- Replace water pump.

The pump that was removed was GM 12566029 As stamped on the pump- visible in pics.
Paperwork shows the replacement pump as part # 12637479.

Heres the failed part--- the weep hole is visible. I spun the pump- felt smooth. So I dont know what the noise I heard was?





I went home and looked over the job-
I figured they had to somehow drain or suck out the coolant so it wouldnt leak when they removed the water pump.
there was no sign of a massive leak from the pump- from it being removed. But there was signs of coolant in the area below the radiator cap. (could be they overfilled? or some was spilled while removing it.... but this isnt of concern. Ive drained out coolant before and also end up with similar results. This will probably wash away with tommorrows rain). This is looking from the top of engine down.. and from the bottom looking up



To get to the radiator cap- they have to remove the big plastic shield. You can see the fasteners were removed.
This one took a little bit of damage. scuffs.



the pump installed. You can see the white sealant on the pump




So I always thought they removed the tire and wheel well liner completely to do the pump...But upon closer inspection of the fasteners...
theyre all dirty-- no signs of them being removed.





But I finally figured out how they did it. towards the bottoms- theres a piece of plastic that is bent... these fasteners showed signs of being removed
So it appears that if the vehicle is on a lift--- the person working from undeneath- can remove these fasteners- and have access to the pump.
(I think if youre at home-- you would have to remove tire and wheel well--- or remove tire and sort of follow their example of loosening the flap).



In this shot- you can see that theres signs of the Lower A-Arm getting 'cleaned'-- proabably by their shirt as they performed the repair. (leading edge).



I then sprayed a little simple green- and wiped down the area- so that I can have a reference- in case more coolant leaks.



the reservoir was past the Full mark by about an inch. I suspect most will get sucked back in as any air in the system is expelled.

I also asked if they performed any work on the OLM. The service adviser said there was no outstanding recalls on my vehicle. So nothing else was done to the vehicle. I had not asked for anything else- so only the pump was done.

As I drove home- vehicle shifted normally and I had no sense of engine operating differently. Ill monitor the OLM to see the rate drop.

They also performed a multipoint vehicle inspection. All was ok. They list the tires at 7/32 on all 4.
Brake linings where checked. they show up as the fronts at 5mm and rears at 6 MM.

When I got home- I loosened the front pass tires lug nuts and torqued them to 140.
Ill have to do the other 3 tommorrow.

rbarrios I want to thank you for this write up. My wife is on a trip with her family and just had this classic pump failure. The first signs started to happen when she drove over the grapevine in California heading to southern california and is notorious for overheating vehicles. She called me letting me know that she pulled off to the side of the road to cool off and at that time her guage was at 230 and climbing rapidly with the A/C off. This shouldn't have happened because of the extra cooler on the radiator from the tow package but it did and I told her to check the coolant and it was empty? She has some water in the car and put 1 liter in drove the rest of the way to Southern California without overheating again. I thought that this was a fluke but it was actually the first sign of failure. She got to her parents house and her dad to add more dexcool and there was no fluid on the ground which was sign #2 so thinking everything was fine they packed up and drove to idaho at night when it was cool so no problems till yesterday when she noticed fluid dexcool on the ground and she had to put more than a gallon of dexcool in which was the final sign. It's now at GMC in Pocatello getting a water pump replaced.
This write up is amazing and really hit the nail on the head. Thanks again!

:cheers:
Will