There are 7 owner-reported engine complaints for the 2018 Audi A5in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
I own a 2018 Audi A5. Many critical cooling system parts — including the thermostat housing, water pump housing, radiator end tanks, breather tubes, and quick-connect hoses — are made of plastic and sit in constant exposure to coolant temperatures over 200°F. Over time, these components become brittle, crack, and fail prematurely. Recently, the plastic breather/return hose between the coolant reservoir and the radiator broke apart during routine service due to brittleness. When these parts fail, coolant leaks quickly, which can cause sudden overheating, engine damage, and potential vehicle disablement while driving. Based on owner reports and my own experience, this appears to be a widespread issue across Audi/VW vehicles of this generation. I request that NHTSA investigate whether the use of plastic in these high-heat, high-pressure components represents a design defect that creates a safety hazard.
The vehicle has 36000 miles on it and the oil cooler has failed. The car is meticulously maintained. This failure compromises the ability for the engine to cool properly. Because of the failure, coolant is then forced into the engine oil potentially destroying the engine. Engine replacements are 10,000 for these types of cars. Audi is aware of this issue and should repair all vehicles with this known issue
Engine shuts off occasionally whilst cornering at very low speed. No warning. Been happening for several years.
My complaint is that Audi USA refuses to cover my damages and repair cost for the failed AC Evaporator that is covered under their warranty extension # AWA-21-01. Audi has a known issue for A/C Evaporator. The vehicle AC issue was immediately diagnosed by an independent mechanic who only diagnosed the issue and recharged the system until the Audi dealership had availability to inspect and perform the repair. Jim Ellis Audi was told of the issue and how using a sniffer tool the leak was found inside the cabin. Jim Ellis Audi said they would have to run their own diagnostic and if they found the leak that Audi would cover it. They did not find the leak and did not use the sniffer tool and claimed they detected the wrong refrigerant and would recharge it with the correct refrigerant. I had no recourse at this point only knowing my issue was not fixed. I was told that if it happen again to bring it back and they will credit the repair and perform further diagnostics. I felt ignored and opted for a different Audi dealership (Audi Marietta) Almost 6 week later the refrigerant has leaked again and I took the car to Audi Mariette with the same AC issue. The Audi Mariette dealership confirmed the Evaporator failure and performed the repair. I contacted Audi USA requesting a refund for the cost for Eurofed chargers ($298.26) and Jim Ellis Audi charges ($419.84)and was denied claiming the the failure was a result of the wrong refrigerant. I challenge Jim Eillis Audi at the time for the failure to properly diagnose the issue and only performing a band-aid repair of recharging and allowing refrigerant gas to leak into he cabin for a second time. When I asked what was the wrong refrigerant they detected, they could not tell me. I think Jim Ellis dealership is trying to cover their mistake and poor workmanship. Audi USA refuses to escalate my complaint. The fact remains that the evaporator initially failed all cost should be cover by Audi.
I am experiencing an oil leak, the car has 49000 miles and Audi has issued a TSB, yet upon my outreach to Audi North they are aware of the issue of leaks developing yet have not offered either warranty extensions or a recall yet.
Large coolant leak due to faulty plastic thermostat and water pump which can cause overheating, catastrophic engine failure, and fire, putting consumers at risk. The thermostat housing has been replaced by the dealership, but not the water pump, just the water pump seal. There were no warnings prior to the failure, and was only diagnosed after a visual inspection under the vehicle.
The contact owns a 2018 Audi A5. The contact stated that while driving at various speeds, the gears unexpectedly shifted. Additionally, on one occasion, the vehicle lost motive power for two full days. The vehicle was later able to restart. No warning lights were illuminated. The vehicle was taken to a local dealer, where the Engine Control Unit (ECU) was replaced; however, the contact stated that the failure recurred. The vehicle also experienced a loss of power steering. Additionally, the contact stated that the vehicle was taken to various other unknown dealers; however, the mechanics were unable to duplicate the failure. The vehicle was not repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 16,000.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026