2002 Chevy Air Pump Failure

I was hoping someone might have a suggestion I'm on my 6th emissions air
pump on my 2002 Impala 3.8 V6. The first 5 were on Chevy and I thouht they
finally solved the problem but 8,000 later the dreaded check engine light
came on and it was the air pump one more time. I got the pump from the
mechanic and after taking it apart I found that the failure was caused by
water ,black exhaust smelling water, in the motor housing itself. I asked
the mechanic if they checked the function of the check valve from the
exhaust and they said it seem to be working correctly.

The chevy dealer who did the first 5 pumps said that water has gotten into
the fan housing and rusted out the fian blades which seems interesting since
the blades are plastic! They did replace the check valve the last time they
replaced the pump and the intake upgrade has been installed.

I'm hoping someone might have a idea on how to get this pump to last a
little longer I like the car and really don't want to sell it.

Thanks Tim