Your car relies on you to maintain it regularly and not to gun it across any rivers, even if there are free Thickburgers on the opposite bank. Keep your vehicular promises with today's Groupon: for $16, you get a 20-step oil change at Smithfield Fast Lube (a $39 value).

To commence your car's comprehensive 20-step oil change, a skilled technician will clean out dirty, worn-out oil and replace it with up to five quarts of fresh, clean lubricant. In addition to installing a new filter, the Smithfield Fast Lube staff will give your automobile a thorough inspection, checking the power-steering fluid, the radiator coolant, the tire pressure, the NASA command center in the trunk, the brake-fluid levels, and the transmissions fluids. With Pennzoil products coursing through your vehicle's bloodstream, its engine will be cleaner and better protected against clots of harmful sludge.

The devoted staff will also vacuum the front interior of your car, grease the chassis, and scrub the outside windows until they are as spotless as Mother Theresa's criminal record. Chat with one of Smithfield's friendly, knowledgeable team members if you have a question about your car's nervous system that you're too embarrassed to ask your bionic biology teacher.