1990 Pontiac Bonneville Water Pump

MINORMAN

MEMBER
1990 PONTIAC BONNEVILLE

Engine Performance problem
1990 Pontiac Bonneville 6 cyl Front Wheel Drive Automatic 223k miles

The serpentine belt was suddenly detached when I started my ’90 Bonneville. I soon found radiator fluid leaking under the engine. After some investigation, I noticed the water pump hub was bent slightly. The water pump only rotates about 60 degrees with ease and a full turn with force. Rubber marks on the pump hub correspond with the bend on the water pump hub.

What would have caused this problem to occur?

Helpful hints: I live in a cold weather climate. The car has 223k miles. The car still turns over and idols. The water pump was approximately three years old. Occasionally while driving, the battery idiot light has been turning on for short periods of time. Could this have been simply a loose belt problem?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi:
A loose belt could cause the alt light to come on. Make sure the belt tensionier is working properly. As far as the water pump, that is an unusual problem. The only thing I could attribute it to is the bearing insid the pump went bad, locked and the engine forced it to turn bending the shaft.

As far as the bat light, when you replace the belt, make sure there is good tension on it. If there is, if the problem worsens, have the alt checked.

Let me know if you have any other questions.
Joe
Positive feedback is appreciated.