We are trying to find out if anyone knows of problems with GM Pontiac Bonneville's plastic upper exhaust manifold. We own a 2000 Bonneville with 83K mileage. The plastic manifold exploded while trying to start the car. We are trying to resolve this with GM at this time. We learned that this has occurred before with other year Bonneville.

- Castro Valley, CA, USA

The contact stated he took the vehicle to a dealership to have it serviced on February 14, 2003. At that time they had to replace the intake manifold and flushed the motor. On October 7, 2004 the contact took the vehicle to another dealership to have the vehicle serviced. They found anti-freeze was leaking into the engine. The intake manifold needed to be replaced. On December 22, 2005 he took the vehicle back to the dealership to be serviced. Again the intake manifold gaskets needed to be replaced and the repairs were made. The window motor and regulator were replaced. Updated 02/07/06.

- Selden, NY, USA

During a routine inspection, the mechanic informed the consumer that the upper intake manifold had cracks.

- Henagar, AL, USA

Leaking intake manifold on 3.8 engine. Plastic intake cover poor design, not holding up beyond forty thousand miles.

- Mansfield, OH, USA