As many as it takes. In 1998, Dodge pickups were available with a 3.9 liter Magnum V6 (1500 only), 5.2 liter Magnum V8, 5.9 liter Magnum V8, 8 liter Magnum V10 (2500 and 3500), and 5.9 liter Cummins 6BT diesel (2500 and 3500). Each engine has different oil capacities, and we have no way of knowing which one you have without you telling us.
The engine holds twelve quarts.
5 quarts
4.5
A 1998 5.2L holds five quarts.
5
13
A 1998 Dodge Avenger requires 4.0 quarts of oil (this applies to both the 2.0L 4-cyl and the 2.5L V6)
The 5.9L Cummins engine holds twelve quarts of engine oil.
5.2 and 5.9L hold 5 quarts 4.7L holds 6 quarts 5.7L holds 7 quarts
5
5 with a new filter
Total capacity is almost twelve quarts.