
Several owners of Audi's first electric model, the e-tron, have had to replace the rear motor and differential on cars with moderate mileage. Why is this happening, and can it be prevented?
The Audi e-tron was Audi's first commercial electric model. It gave the market a signal that the Volkswagen Group was ready to electrify its car fleet. The year was 2019. With tax and duty exemptions, the electric Audi became widely available in Norway. For the same price as a mediocre station wagon, you could get a large and pompous Audi SUV the size of an Audi Q7. Today, according to Elbilstatistikk.no Over 30000 Audi e-trons have been registered (50 and 55 ed. note). The figure includes both cars distributed via brand dealers and parallel imports.

A known issue
I could easily pick out 10 ads on Finn.no where it was stated that the e-tron's rear motor had been replaced. Probably the tip of the iceberg. The car with the lowest mileage only had 66000 km on the odometer. I also find the problem discussed in posts on online forums. An American Audi owner had to pay $10700 to fix the car. A Norwegian car seller quoted 100000 kroner – another 110000 kroner. The amount is not of great interest at the moment, as most cars sold in Norway are still under new car warranty. The high price will probably raise more concern as the warranties expire. In the US, Audi has extended the warranty period for this specific problem. Perhaps Audi will do the same in Norway – at its discretion.
Coolant on the way out
In short, the problem occurs after coolant leaks around the rear engine. The leak occurs at a sealing ring. The engineers at Audi have actually foreseen a problem with excess water (coolant and/or condensation) and made a container on the underside of the engine to collect this. The container should be replaced at the 30000 km service. Normally, you will only find a splash of clear water there. But when the sealing ring does not do its job, the container fills up faster and liquid penetrates vulnerable components.

There are videos on YouTube that show you can empty the excess water tank yourself. It is accessed from the underside of the drivetrain behind a plastic cover.
Scope and prevention
Currently, there is only speculation about why the sealing ring fails. One theory is that coolant deposits adhere to the ring due to heat. What strengthens this theory is that the problem seems to affect a larger proportion of car owners in the United States than in Norway. Hours of driving at highway speeds with subsequent fast charging and hot climates can create high temperatures in the batteries. Even though the Audi e-tron has separate cooling ducts for batteries and motors, the theory cannot be ruled out.
On a forum page, there is a discussion about whether to check the excess water tank more frequently to detect leaks at an early stage before vulnerable components are damaged, or just replace the sealing ring. I suspect that the branded workshops will replace the entire cluster consisting of engine, differential and control box anyway, rather than unscrewing everything to replace the sealing ring. Furthermore, the excess water tank is not suitable for inspection outside of service intervals.
Consequences
When new car warranties start to expire, you no longer have any legal claims against the dealers. But since it is a manufacturing defect, good customers may experience having the repair carried out under an extended warranty. Owners of parallel-imported cars have no claims beyond any local used car warranty. Car owners with service performed outside of the brand's workshops may also risk being met with a cold shoulder after the warranty has expired. Eventually, when all car owners have to cover the costs themselves, we may see well-maintained cars with low mileage being sent for recycling. Audi will not be the first in this case.
The question many may ask: Does this apply to all cars?
It is too early to draw any conclusions. We do not know the exact extent, but since the defect is already well known, we must assume that the number may be significant. Of the ads I checked, they are about cars registered between 2019 and 2021, repaired relatively recently in 2024 or 2025. There does not seem to be any connection with mileage, but age may be important. The third aspect is whether driving patterns and climate may play a role. Time will tell.
Repair instead of replace?
The YouTube video below (click on the image) shows the dismantling of a water-damaged rear engine cluster from an Audi e-tron. The video claims that the engine is made by Volkswagen and that it is also installed as the front engine in the Volkswagen ID.4 GTX. Since the ID.4 GTX with 4-wheel drive primarily drives the rear wheels, the front engine provides the the front wheels when needed. The Audi e-tron primarily drives the front wheels, and this engine is located at the rear.

The mechanic discovered water in the steering box and noticed a strong, nasty smell from the gears in the differential, which he suggests may be caused by coolant mixing with transmission fluid. The point is that the electric motor appeared undamaged. The differential also looks like it can be cleaned and reassembled. Should thousands of owners of aging Audi e-trons experience problems with the rear motor, perhaps specialist workshops will emerge that can repair for half the price?
Should the problems also appear in the Volkswagen ID.4, they will have full order books.
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