Our 2005 GC (3.8l, 109K miles) has recently developed a noise under the hood, that is coming from the serpentine belt side of the engine. It's like a tapping/knocking noise and it doesn't affect engine performance in any way. I don't have a stethoscope, so it was taken to our garage for an opinion on what is causing the noise. Their guess is that it's the water pump.

Is that a plausible explanation? I presume that, if they're right, then it's the bearing/pulley gone bad? We don't seem to have any leaking or overheating issues.

They quoted $320 to replace the pump. From a quick search it seems that I can pick up the pump myself for $40 and some fresh coolant for $20. Is it worth tackling myself or are there some gotchas? Only thing I've seen so far is that it can be a pig to wrestle the pump out and the new one in, due to clearance.

Thankyou!

 

On my 2002 the water pump failure was silent. My AC compressor clutch bearing made noise. More like a whrring.

The root cause was my Harmonic balancer rubber dampener failed causing it to run untrue anD vibrated the AC clutch bearing outer race to bore out of whack.

Jack it up. Remove the tire. Take the cover off and observe and listen for anything that presents its self.

Gluck.

 

Take the belt off and turn each item by hand and feel for any roughness in the bearings to determine the cause of the noise.

If it is the water pump and you need to replace it, make sure the pump you get does not have a plastic impeller. The plastic impeller can slip on the shaft or even come apart.