1998 Pontiac Montana Van, Problems, Defects and Repairs.

The 3.4 engine is a time bomb.

This engine family has a history of lower manifold gasket failures. I'd be suprised however if on a 98 model it hasn't already been replaced. Suggest frequently checking the coolant level in the underhood reservoir. Sometime in the 2003 MY the gasket design was changed but I don't know if that was a permanent fix. I've got 132k on mine but change the gasket a couple years ago. The engine can be noisy, often referred to as cold start tick, but the noise mostly goes away after a few minutes of operation. Still use 5W-30 and oil comsumption is nil.