1. Locate your owner's manual: This is the most reliable source. The manual will specify the oil capacity for your engine.
2. Check the oil fill cap: The oil fill cap often has the capacity printed on it.
3. Consult a reliable online resource: Websites like the Chevrolet website or a reputable parts website (like AutoZone or Advance Auto Parts) allow you to search by year, make, model, and engine to find the correct oil capacity. Be sure you enter the correct information!
Without knowing the year and engine of your Suburban, I cannot provide the correct oil capacity.