2011 Acura RDX: What is the oil type and capacity?

Each variation of the 2011 Acura RDX comes with the same 2.3 liter 4Cylinder turbocharged engine, so regardless of which configuration You're running, Your engine oil information will always be the same. You'll use 5.0 quarts with filter, or 4.8 quarts without filter of SAE 5W-30 full synthetic motor oil. In its absence in emergency situations, it's possible to swap in SAE 5W-40 for the short term. This substitution, however, is not recommended if You can avoid it. Oils with higher numbers in their weights are thicker than their lower-numbered counterparts. This introduces friction into Your engine's operation, which will lead to premature wear and tear. Over time, this can cause early engine failure. Therefore, always use the manufacturer's recommended oil with the lowest weight, even if it costs You a bit more per change.