The 2008 dodge avenger takes4.2 liters (4.5 quarts) of sae 5w-30 engine oil. this is a very popular synthetic fluid because it's suitable for a wide variety of engines in a large range of climates. the manual for this vehicle says to change the oil every 6,000 miles or 6 months, whichever you arrive to first. however, your maintenance schedule will be based on your driving habits. it's a good idea to get in the habit of checking your oil routinely, even when it's not time for it to be replaced. if this fluid is permitted to get low or old, serious engine damage can occur. all moving components in the engine rely on oil to be lubricated. if you're changing this fluid yourself, a few popular 5w-30 products include amsoil signature series, mobil 1, pennzoil ultra platinum, and castrol edge.
The correct motor oil type to use in a 2008 dodge avenger 3.5l is synthetic 5w-30.