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Engine & cooling

2018 Audi A4 Engine problems

Owners have filed 6 complaints about the 2018 Audi A4's engine & cooling with NHTSA - 14% of all its complaints, most recently on July 1, 2026. Stalling, loss of power, oil consumption, overheating, head gaskets, timing chains and engine failure.

Complaints
6
Recalls
0
Crashes
0
Fires
0
Injuries
0
Deaths
0

Engine complaints

Engine & coolingFuel system

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...

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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.

Filed Incident Unknown or other · Engine · Fuel / propulsion systemNHTSA 11747848
Engine & coolingFuel system

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 as: "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...

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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.

Filed Incident Unknown or other · Engine · Fuel / propulsion systemNHTSA 11747808
Engine & cooling

The contact owned a 2018 Audi A4. The contact stated that while driving at an undisclosed speed, there was fluid leaking from the front of the vehicle. No warning lights were illuminated. The contact also stated that while the vehicle was parked, there was a puddle of fluid leaking from the front of the vehicle. The vehicle was taken to an independent mechanic, where it was diagnosed and it was determined that the water pump had failed and needed to be replaced. The vehicle was not repaired. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 92,000.

Filed Incident Engine and engine coolingNHTSA 11717605
Transmission & drivetrainElectrical systemEngine & cooling

See attached document for complaint

Filed Incident Power train · Electrical system · EngineNHTSA 11607215
Engine & cooling

Water Pump prematurely failed. Upon self inspection, I noticed the coolant reservoir was below the minimum requirements. I asked the dealer to inspect, and they determined the cause was a faulty water pump. At around 50,000 miles, this water pump should not have failed under normal use. I am fortunate I self inspected, as continued use may cause premature engine failure due to overheating. Overheating would cause spontaneous vehicle operation failure during normal driving conditions, stalling the vehicle on a road or highway, putting myself and others at risk for impact.

Filed Incident EngineNHTSA 11489365
Transmission & drivetrainEngine & coolingFuel system

Engine malfunction prevented the vehicle to engage and a significant lag. Correction of the failure has been attempted twice and a third attempt to correct malfunction is currently in progress with no movement as of yet. Gas tank has been drained and refilled and did not correct issue. Definitely not a gasoline type issue.

Filed Incident Power train · Engine · Fuel / propulsion systemNHTSA 11349755

Audi A4 engine complaints by year

A4 engine problems, every year

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Source: U.S. National Highway Traffic Safety Administration (NHTSA) complaints and recalls, checked . Complaints are owners' own reports and are not verified. How we use the data

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