02 Venture New Water Pump Noise

[5.O Canada]

I just replaced the factory water pump on my '02 Venture van, at 94000 miles because it was leaking. I installed a new pump, Napa (Gates) #41020 ($30 here in Canada). It's working and not leaking, but after running about 2 minutes, it starts to make a "buzzing" noise, not too loud, but doesn't sound right to me. Are there any conditions other than defective bearing that could cause this? I torqued the bolts to the spec 89 in-lbs (7ft-lbs) in 1/4 turn increments and used Permetex "Water Pump RTV Gasket Maker". The new pump has a stamped impeller, the factory pump had a cast impeller. Is the new Gates pump poor quality? i.e. should I have gone with the GM pump? Thanks.

[Tech II]

3.1/3.4? Why didn't you use the gasket that comes with the pump?

If the noise is coming from the pump, make sure you have burped all air from the system, to eliminate cavitation......otherwise, I think it may be a bearing.....

[5.O Canada]

It has the 3.4L engine (intake gaskets done in 2008). I used the gasket that came with the pump and the RTV sealant as well. Good idea about air in the system. I will bleed the system. Thanks!

[Tech II]

I usually coat the gaskets with never seize.....if you have to take that pump off, the gasket will come off easy with never seize....

[5.O Canada]

It's now been about 2 months and the noise seems to have gone away, so I think it was air in the system, which finally worked its way out. Thanks for the replies.