general problems of the 2018 Audi A4

The vehicle displayed a low coolant warning and the coolant reservoir was low. Audi dealer service records dated on or about 02/14/2025 document the concern “client states low coolant warning was on, coolant reservoir is low, diagnose and advise. ” the dealer performed coolant-related work involving the thermostat gasket / coolant hoses or connections to the coolant reservoir, ran the vehicle to operating temperature, and rechecked. The concern is being reported because the coolant loss/refill issue continued or remained unresolved afterward. The exact source of coolant loss is unknown, but it may involve the water pump, thermostat, coolant reservoir, coolant hoses/pipes, pressure loss, internal coolant leak, or coolant loss that evaporates before leaving visible residue. This is a safety concern because coolant loss can lead to overheating, warning messages, limp mode, loss of propulsion, engine damage, steam/smoke, or stall risk while driving. No crash, fire, injury, or fatality occurred. The vehicle/component is available for inspection, and Audi service records, coolant-system communications, photos, and water-pump/coolant-related documents are available.

The fuel filler door/gas door intermittently fails to open, preventing normal access to the fuel filler area. This appears to involve the fuel door latch, release mechanism, lock actuator, body component, electrical control, or related wiring/module issue. This is being reported as a safety concern because inability to open the fuel door can prevent refueling when fuel is low. If the vehicle cannot be refueled, it can create a stranding risk or loss-of-propulsion risk, including in traffic, at night, on a highway, or in an unsafe location. The issue also creates driver distraction and uncertainty because refueling access is not reliable. No crash, fire, injury, or fatality occurred. The vehicle/component is available for inspection, and photos/video, service communications, and repair records are available if requested.

The engine oil level has been gradually dropping and has required monitoring and/or adding oil between normal service intervals. The exact source is unknown. It may involve abnormal oil consumption, an external oil leak, internal engine oil consumption, pcv/oil separator issue, turbo-related oil consumption, gasket/seal issue, or oil loss that is not leaving an obvious visible puddle. This is being reported as a safety concern because low engine oil or abnormal oil loss can lead to low oil pressure, warning messages, engine overheating or damage, smoke, oil contacting hot engine/exhaust components, limp mode, stalling, or loss of propulsion while driving. The issue should be inspected rather than treated as normal maintenance unless a proper diagnosis confirms normal operation. No crash, fire, injury, or fatality occurred. The vehicle/component is available for inspection, and oil-level/refill records, repair records, photos, receipts, and service communications are available if requested.

The short-term mpg / fuel-consumption display gives illogical and inconsistent readings. The display can show a significant drop in short-term fuel economy after the vehicle has been parked, locked, and not running, as if the system is incorrectly factoring parked/off time into the mpg calculation. This suggests a possible fault in the onboard computer, instrument cluster, fuel-consumption calculation, sensor input, software, ecu/module logic, or related electrical system. This is being reported as a safety concern because inaccurate fuel-consumption or range-related information can mislead the driver about fuel usage and remaining range, and it may indicate a broader vehicle electrical/computer/sensor malfunction. The concern is also part of a broader pattern of electrical or driver-information issues, including other intermittent warnings and display-related concerns. No crash, fire, injury, or fatality occurred. The vehicle/component is available for inspection, and photos/video of the display, service communications, issue lists, and related electrical-system records are available if requested.

On December 29, 2022 as I was driving my engine light came on, the fuel gauge registered empty (I had over a quarter tank of fuel at the time), and my miles till empty display in the upper left of the instrument cluster went blank. I took my Audi to my Audi dealer and their recommended repair was as follows: fuel tank: after removing fuel pump and level sensor we found that the secondary fuel level sensor is built into the fuel tank is faulty. Recommend replacing the tank and fuel pump with the tank. Their reason was that if the fuel tank failed it could cause a potentially hazardous situation for the driver and passengers.