An Audi dealer has just diagnosed my 2018 S5 Cabriolet Prestige with vacuum system contamination caused by water pump failure. I had requested the diagnostic due to small coolant leaks on the engine and loss of coolant in the expansion tank. No warning lights and no overheating yet. Not yet aware of any loss of performance. I have been advised it is unsafe to continue driving the car. Dealer has quoted me $7800 estimate to repair the car. Purchased the car in 2021 as a Certified Pre Owned vehicle, and it now has about 84K miles on the OD.
The worst 2018 Audi S5 problems
Ranked by number of owner complaints. Mileage and cost come from what owners wrote.
- Engine9
- Airbags3
- Brakes3
- Visibility3
- Driver assistance2
Problems by type
Tap a problem to see which part fails, at what mileage and in which other years.
- Engine9
- Airbags3
- Brakes3
- Visibility3
- Driver assistance2
- Electrical2
- Seat belts2
- Transmission2
- Body1
- Fuel system1
- Seats1
- Steering1
- Suspension1
Recalls 2
Air bags: sensor: occupant classification: front passenger
- What is wrong
- Volkswagen Group of America, Inc. (Audi) is recalling certain 2017-2020 A4 Allroad, A4 Sedan, 2018-2019 RS5 Coupe, 2019 RS5 Sportback, 2018-2020 A5 Cabriolet, A5 Coupe, A5 Sportback, S4 Sedan, S5 Cabriolet, S5 Coupe, and Audi S5 Sportback vehicles. The cable connecting the seat heater to the Passenger Occupant Detection System (PODS) may have a contact fault, causing the software to misdiagnose a malfunction and disable the passenger air bag.
- Risk
- A disabled passenger air bag increases the risk of injury in the event of a crash.
- Remedy
- Dealers will replace the connecting cable and either the heating mat or entire seat cover, free of charge. Owner notification letters were mailed January 7, 2022. Owners may contact Audi customer service at 1‑800‑253‑2834. Audi's number for this recall is 74E3. This recall is an expansion of Recall 19V‑547 (74D9). Vehicles previously repaired under 19V‑547 will need to return for the new remedy.
Recall number 21V874000 · Recall details
Air bags: frontal: passenger side: inflator module
- What is wrong
- Volkswagen Group of America, Inc. (Audi) is recalling certain 2018-2019 Audi RS5 Sportback, 2018 S5 Cabriolet, S5 Sportback, S5 Coupe, S4 Sedan, A5 Cabriolet, A5 Sportback, A5 Coupe, and 2017-2018 A4 Sedan and A4 Allroad vehicles. Oxidation on the Passenger Occupant Detection System (PODS) connecting cable may cause the software to misdiagnose a malfunction and disable the passenger air bag.
- Risk
- A disabled passenger air bag increases the risk of injury in the event of a crash.
- Remedy
- Audi will notify owners, and dealers will install cable ties to the harness, free of charge. The recall began September 9, 2019. Owners may contact Volkswagen customer service at 1‑800‑893‑5298. Audi's number for this recall is 74D9.
Recall number 19V547000 · Recall details
Technical service bulletins for the 2018 Audi S5 825
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- This bulletin provides informaiton on the use of the PICO-NVH tool (VAS 611 015).
- This bulletin proides service information when there is a prompt to take over the steering wheel (hands...
- This bulletin provides information when the starter battery is discharged or malfunctioning.
- This bulletin provides information when there is an Audi pre sense warning, warning jolt, or brake...
- This bulletin provides information to aid in diagnosing the vehicle locking system.
- This bulletin provides information when the engine is not runing smoothly; all gas engines.
- This bulletin provides information on VIN plates, Safety Certification labels, and ordering procedures.
- This bulletin provides infomraiton when the exterior lights have moisture accumulation.
- This bulletin provides information for reporting safety related information to the manufacturer.
- This bulletin states that technicians are required to report to the manufacturer when a vehicle has...
2018 Audi S5 fuel economy
Official EPA estimates in miles per gallon (MPGe for electric). Ranges cover trims that share the same engine.
| Engine | Drive | City | Highway | Combined |
|---|---|---|---|---|
| 3.0L 6‑cyl | AWD | 20-21 | 29-30 | 23-24 |
What 2018 Audi S5 owners say
Most recent owner complaints, unedited.
Component/System: Passenger Occupant Detection System (PODS) / Airbag system — Recall 74E3 / the federal safety agency 21V874. What Happened: The passenger airbag may switch off even when the seat is occupied due to a faulty PODS wiring connection. The warning message “Passenger Airbag Off” appears with a chime. This is an active safety recall that was issued before I purchased the vehicle, but the recall was not disclosed at the time of sale. Safety Risk: If the system shuts off the airbag incorrectly, the passenger may have no airbag protection in a crash, creating a serious risk of injury or death. Inspection Availability: Vehicle is available for inspection. I live on the Big Island of Hawaii, where there is no Audi-authorized repair facility. Reproduction/Confirmation: Symptoms match the known recall defect. Audi has confirmed the recall applies to my VIN, but no local dealer exists to inspect or repair it. Manufacturer/Dealer Inspection: Audi has refused to cover shipping to the nearest authorized dealership on Oahu, which is the only location where the recall can be performed. Therefore, the defect has not been inspected due to lack of accessible remedy. Warnings/Symptoms: Airbag warning light illuminates and a message appears indicating the passenger airbag is off, along with a chime. Additional Notes: I cannot safely use or sell the car because the required safety repair is inaccessible. Audi’s refusal to provide transportation makes it impossible to complete the mandated recall.
VEHICLE Year: 2018 Make: Audi Model: S5 Prestige Trim: 3.0 TFSI (EA839 V6 Turbo) Mileage: 86,000 Engine Code: CWGD COMPLAINT TITLE Latent Engine Failure – EA839 Piston Skirt + Rocker Arm Defects – Dealer Broke Engine Cover, Left Wiring Harness Dangling – Audi Denies Despite Having DIY Receipts For Maintenance DESCRIPTION At 86,000 miles, my 2018 Audi S5 Prestige suffered internal engine failure from metal debris and cylinder wall scoring. Dealer borescope showed: Metal in oil filter (bearing + non-ferrous “other metal”) Deep scoring on multiple cylinders No check engine light. No power loss yet. Still drivable — but seizure is imminent. DEALER NEGLIGENCE AT [Audi Of Chantilly] (Penske Automotive Group): Engine cover broken — not reported Wiring harness retainers/harness clips left undone on both sides after spark plug removal → Improper reassembly risks damage to harness and engine/components — safety hazard. This matches TWO known EA839 defects: Piston Skirt Cracking – Sept 2025 Warranty Extension covers identical symptoms (debris + scoring). Denied only for 6,000 miles over 80k cap. Pre-06/2018 Rocker Arm Needle Bearing Failure – Audi revised mid-2018 (PN 06M109417H → 0P2109417, double bearing size) because originals shed metal. Garage Auto Sports: “Known to fail… Audi fixed it.” Link AudiWorld: 200+ cases Link AoA DENIAL – FALSE “Over mileage” → Rocker defect has no cap “Undocumented maintenance” LIE → All oil changes DIY with Audi 508.00 oil + OEM filters → Amazon invoices attached → Never asked for proof $32,000 quote. 100% denial. SAFETY RISK Sudden seizure at speed No warning Dealer damage worsens risk REQUESTED ACTION Investigate EA839 2017–2018 for piston + rocker failures Recall / extend warranty for pre-06/2018 builds Probe denials without proof request + dealer negligence ATTACHMENTS Denial letter Dealer Diagnostic 32k Quote Borescope report Amazon receipts Broken cover + undone retainers photos Screenshots (links above)
Vacuum line has coolant due to water pump failure and over heating of engine. Whole water pump and coolant reservoir plus hoses need to be replaced before additional damage to vehicle.
To Whom It May Concern, I am submitting this complaint to report a mechanical issue with my 2018 Audi S5 Sportback. Around 57,000 miles, the engine began making a noticeable ticking noise, which I have been advised is due to failing rocker arms. This issue has raised serious concerns, as it can lead to engine misfires, reduced performance, and potentially catastrophic engine damage if left unresolved. The problem appeared without warning, despite regular maintenance and no prior engine alerts. I believe this may be a defect affecting other Audi models with similar engines, and I urge the federal safety agency to investigate whether a recall or technical service bulletin should be issued. Vehicle Information: Make: Audi Model: S5 Sportback Year: 2018
While driving, my Audi overheated randomly, started smoking, had to be towed. Had 72,800 miles, was serviced by Audi at 70k miles and all prior recommended services. Towed to Audi dealership, quoted 29k in engine repairs, Audi could never tell me why engine overheated. Would not cover any expense because “i didn’t buy it there”. Insurance denied two claims because Audi reported it as engine failure although they couldn’t prove what happened to cause the heating, said it was one of the worst engine overheating they had seen. Prior to overheating, service driver system popped up for the first time. Temperature gauges were normal. Will not start or run since. No accountability taken by Audi at all, even through corporate. I believe my safety was at risk because the engine would have caught on fire had I not of noticed or pulled over. A Good Samaritan even pulled behind me to check on me because they saw it smoking in passing. I have a video of Audi inspection. Date is estimate of event, I would have to research. Vehicle was purchased by prior owner as cpo from Audi at 30k miles and serviced since at same Audi dealer every recommended service and prior if issue arose, I have all service records.
•Parking Brake Issue: The parking brake failed to disengage after stopping, leading to an accident. •Intoxalock Device Malfunction: The Intoxalock device malfunctioned with incessant beeping and intermittent error messages, causing distractions. •Previous Complaints and Lack of Resolution: Previous complaints about the parking brake and Intoxalock device were dismissed without proper investigation or resolution. •Parking Brake Failure: The parking brake failed to hold the car, leading to uncontrollable movement and collision with an obstacle. •Intoxalock Device Malfunction: The Intoxalock device malfunctioned, causing distractions and contributing to the accident. •Financial Burden and Lack of Refund: Intoxalock placed the account in collections despite timely payments and failed to refund lockout fees. •Safety Concerns: Parking brake malfunction and faulty Intoxalock device. •Installation Issues: Unprofessional installation and lack of functionality. •Customer Impact: Dangerous situations and potential vehicle damage. Intoxalock’s faulty installation and negligent response to previous complaints led to a parking brake failure and subsequent accident. The incident resulted in significant damage to the vehicle and highlighted the company’s lack of accountability for customer safety. Legal action is being considered due to the ongoing safety risks and unresolved issues.
After driving for 7 to 8 minutes less that 45 mph, a yellow warning lamp and an audible warning indicating unsafe coolant temperature displayed on the dash. An overheating engine is unsafe for me and drivers near me. I immediately pulled over and turned off the A/C. I then turned on the heater, and after 15 minutes slowly drove 5 minutes to a repair shop (Import Autohaus, Hull Street). The repair shop diagnosed a defective water pump. The pump has not been inspected by anyone other than the mechanics at the repair shop.
I received a coolant overheating message, pulled to side of road. Let vehicle cool off although it just showed coolant warning and actual engine temperature showed normal along with oil temperature. Started car back up and it was ok, drove about a mile, engine started steaming, white smoke out of exhaust, system failure had to pull off and be towed. Engine is destroyed at 72,833 miles.
I was returning home from visiting family. My drive was approx 140 miles home. The car was running/driving normally when I stopped at a gas station to get a snack. When I came back to my car and attempted to start it, it would not start and had camshaft and crankshaft sensor DTC's. I had to tow the car to my repair shop who determined that the issue was the rocker arms. Despite performing regular maintenance above and beyond what the manufacturer recommends, two rocker arms fell apart inside the engine (needle bearings came out) and sent metal through the engine, causing it to need to be replaced. It was later determined that this was a known issue by Audi, and that they redesigned the rocker arms at a later date. The did not issue a recall or any extended warranty for the effected models. This cost me $16,349 out of pocket to repair. I contacted Audi several times and they refused to rectify the issue. I have came across several others who have experienced the same issue. I have supporting documentation as well as part numbers and dates that I can provide upon request. This type of issue is a saftey concern because this can leave a driver stranded. When this issue happend I was over 75 miles away from home. Luckily I was able to find a tow truck and had the funds to cover the expense of having the car towed back to my home town. However, this issue could leave someone stranded in the middle of nowhere if they werent as lucky as I was.
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Questions about the 2018 Audi S5
Is the 2018 Audi S5 reliable?
Owners have filed 26 complaints about the 2018 Audi S5, 4.3 times a typical S5 model year.
What is the most common problem with the 2018 Audi S5?
Engine and cooling, with 9 complaints. Next is airbags (3).
How many recalls does the 2018 Audi S5 have?
2 recalls, covering air bags.
What gas mileage does the 2018 Audi S5 get?
Official estimates for the 2018 Audi S5 range from 23 to 24 mpg combined. The most efficient version (3.0L 6-cyl, AWD) gets 20-21 city and 29-30 highway.
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