Brewed coffee is weak or watery even when using normal amounts of coffee.

Check coffee and settings:

• Use a medium grind suitable for drip coffee, not coarse percolator grind.
• Increase the amount of coffee slightly and ensure the filter basket is the correct Oster part.
• Verify you are selecting the correct brew size and strength setting (if available).

Temperature and flow:

• Observe the brew: water should come out in steady pulses and be quite hot (near boiling) as it enters the basket.
• If the water seems lukewarm or the brew finishes unusually fast, the heating element or temperature control may be underperforming.

Descale the machine to restore proper temperature and flow. If weak coffee persists despite proper coffee use and descaling, a failing heating element or thermostat may need replacement.