Before Mercedes-Benz made its return to Formula One as a constructor in 2010, it was already involved in the sport as a power unit supplier.

Most famously, it supplied power units to McLaren, and one of those power units, a naturally aspirated, 90-degree V-10 is currently up for grabs in an online auction hosted by RM Sotheby's.

Code-named the FO 110 Q, it was one of the engines supplied to McLaren for use in its 2004 F1 car, the MP4-19. The season saw David Coulthard and Kimi Raikkonen driving for McLaren, with Ferrari and Michael Schumacher taking home the titles. It isn't clear if this engine was actually used in a race.

The engine has a displacement of 3.0 liters and in its prime was capable of spitting out 900 horsepower at an insane 18.300 rpm. Currently, the engine is missing its pistons and connecting rods.

At the time of writing, there's just one day left for the auction and the current bid on the engine is 5,000 euros (approximately $5,745). The estimate for the engine, which has been offered without reserve, is between 40,000 and 60,000 euros. For some, even the top-end of the estimate would be a small price to pay to add such a rare piece to their ultimate garage.

Other highlights of the auction include a Mercedes SLR McLaren Stirling Moss and a 997-generation Porsche 911 GT3 RS 4.0.