2018 Audi Q7: What to check before buying

Heavy oil consumption is the main complaint. Low-oil warnings come on often, and some engines need a quart every few hundred miles. Several reports go on to misfires, burnt exhaust valves, failed or melted pistons, and lost compression. Some of these come with sudden power loss or stalling at highway speed. Most of these failures fall between about 68,000 and 86,000 miles, and one engine is called unrepairable. A second pattern is coolant loss from a leaking water pump, reported from under 20K miles to around 56,600. One complaint is listed as crash-related.

A dashboard alert says a front side marker or parking light is defective. Often the light still works or just glows dimmer than normal. The warning can pop up several times a minute with a chime, and owners call it distracting. Independent mechanics have trouble tracing the fault. The dealer fix described is replacing the entire headlamp assembly, with quotes from about $5K to almost $7,000. Owners report that the cost of this repair falls on them.

Rear coil springs break, usually on the passenger side and sometimes on both sides. Most failures land between 60,000 and 70,000 miles. No warning light comes on. Drivers hear a loud pop, bang, or rattle, and that rear corner sags. Some reports also find corrosion at the lower spring mount or leaking shocks. Owners fear a broken coil could puncture a tire or hurt stability. One says adaptive cruise control and automatic emergency braking stopped working. Repair estimates run about $1500 to $2400.

The car locks itself with the key inside. In one case a child was trapped, and that report is recorded as an injury. The Pre Sense system slams on the brakes in turns and at low speeds, sometimes mid-intersection. The fuel gauge can stick and keep showing range until the engine dies on the highway. The MMI screen also reboots over and over, and the backup camera falls back to graphic mode. False side marker warnings come back too, with repair bills over $4,000.

The wheel can seize, or a malfunction warning can appear without notice, sometimes with loss of control on the interstate. One low-speed turn ended with the car striking a curb and spinning. Diagnoses point to a failed steering rack or lost communication with the steering module, at about 60,328 to 64,851 miles. Other reports describe drifting toward the passenger side with cupped front tires, a pecking vibration in right-hand curves, and a wheel that sits off-center from the seat.

Drive system malfunction warnings come with sudden power loss at highway speed. In one case the transmission slipped into neutral while the display still showed drive, and the car would not move. Near a full stop, the stop-start system can leave several seconds with no response to the accelerator. Other complaints cover a failed water pump and thermostat at 59,000 miles, oil use of a quart every 600 miles, Quattro differential noise in tight turns, and the cluster showing P while in reverse.

Front brakes squeal loudly, mostly when backing up. Most reports come from around 20,000 to 27,700 miles. Owners cite a service bulletin for the noise. Dealers turn down the fix once the car is past its age or mileage limit, and some owners only learned of the bulletin by calling Audi directly. New pads do not always stop the noise. In one report the brakes locked briefly at low speed on ice.

Original tires wear out fast and unevenly, often between 6,500 and 17,000 miles. Goodyear run-flats chunk on the outer edges or lose tread sections. Other brands wear in a wavy pattern on the inner half even after an alignment. Dealers call it normal wear or a tire-maker problem and refuse replacement past 12,000 miles. In one crash-related report, a stabilization error appeared and the brakes cut out during a U-turn, and the car hit a barrier.