The haul – weighing 35 kilogrammes (77 lbs) – was discovered as the vehicle was crossing into the city of Cologne, North Rhine-Westphalia from Belgium.
Police had ordered the car to pull over at a motorway truck stop for a routine search.
Crammed inside the spare wheel bay, they discovered 30 bricks of cocaine, the largest ever haul found in a car in Germany.
One suspect – a man from Bosnia and Herzegovina – was arrested.
In a statement on 16th August obtained by Newsflash, Main Customs Office Cologne spokesman Jens Ahland said: “More than 35 kilogrammes in one single car means a new federal record.”
He added: “A 25-year-old male Bosnian national put the 30 typical cocaine ’tiles’ into a carton which he put in the vehicle’s spare tyre compartment.
“Those smuggling drugs usually don’t make it that easy for our colleagues to discover them.”
The suspect – now in custody awaiting charges – was said to have been heading across Germany to Slovenia when he was stopped.
The customs spokesman explained: “A fast check determined cocaine traces on his hands so our colleagues carried out a comprehensive examination of the car.”
The discovery happened just days after 16.4 kilogrammes (36.2 lbs) of cocaine were found in a car coming from the Netherlands.
Two Italian men aged 37 and 42 were arrested after 15 packages containing the drug were found stashed under floor classing beneath the back seats.
Customs spokesman Ahland said: “The drugs smuggled in the two cars have an estimated illegal sale value of EUR 3.7 million (GBP 3.17 million).”
Both confiscations were made around four weeks ago but police delayed releasing news of the arrests to follow up other inquiries.