C63 Oil Cooler Update

C63 Oil Cooler Update

You might remember our earlier post on the C63 Oil Cooler (and if you don’t, here’s the link). After we’ve done some test-fitting and number-crunching, we have an update ready for you:


The above picture is what the stock oil cooler looks like. You can see it in front of the radiator, that little black thing with the AMG shroud attached.


Now this is that exact same car with our Fluid MotorUnion oil cooler attached. We’re still testing on available cars to see if this application could apply to a broad spectrum of Mercedes vehicles. We’ve now confirmed that there at least two different Mercs on which the oil cooler will fit. Either way, here are some specs about our fabricated aluminum monster, compiled by Mike Eastway:

  • The Fluid oil cooler has a 580% capacity increase over stock (~3 quarts)
  • The Fluid oil cooler’s surface area is increased by 205% over stock

Eastway ran a total of five test cycles. These cycles consisted of:

  • Idling until oil temperature stabilized
  • Running the engine at 3000 rpm until the oil reached a temperature of 105 degrees Celsius
  • Idling until the temperatures returned to initial start point, with 5 minutes of stabilization between test cycles

These tests were performed inside with the hood open and a fan approximately one foot in front of the oil cooler. Here are the graphs:


Here, the driving temperature was tested by driving normally (non-spirited) for 30 minutes, followed by 30 minutes of idling. You can see a marked decrease in oil temperature both while driving and idling afterwards when compared to the stock oil cooler.


Here, you can see that as the test cycles continued, the time it took to reach 105 degrees shortened with the stock oil cooler. With our aluminum oil cooler attached, each cycle actually increased the time it took to reach 105 degrees, thanks to the thermodynamic properties and specific heat of aluminum. The properties of aluminum are paramount in keeping temperatures down over longer periods of time, which won’t happen with the setup of the stock cooler.


Once again, the results are pretty predictable. The larger surface area and overall capacity of our oil cooler allowed the oil to reach a stable operating temperature in an almost perfectly consistent amount of time each cycle. As expected, the stock oil cooler continued to slow down its feeble attempt at cooling the oil after repeated cycles, eventually taking almost nine minutes (twice the time of the FMU cooler) to bring the oil down to a stable temperature.

Overall, preliminary testing shows an approximately 115% increase in efficiency over the stock oil cooler, with the heat cycle ratios at a roughly 300% improvement and a stabilized ratio after just two test cycles. The results speak for themselves, and we couldn’t be happier that all of our engineering and number-crunching provided such excellent results in comparison to the stock oil cooler.

Keep your eyes peeled for more information as we continue to do more track and dyno testing of this setup and eventually begin to produce it.

  • Matt
    Posted at 01:23h, 15 February

    How is this coming along? My 2010 c63 can’t run hard for more than 15 minutes of spirited driving. It’s really a considerable let down.

  • GTR
    Posted at 03:44h, 20 July

    Good day, I want to order one for C63 2013.
    Please reply me regarding the details.

  • fluidmotorunion
    Posted at 12:32h, 04 August

    Please e-mail mmarzano@fluidmotorunion.com and we’ll send over a quote!

  • fluidmotorunion
    Posted at 13:03h, 04 August

    Matt, please e-mail mmarzano@fluidmotorunion.com for more information on the C63 oil cooler.

  • George
    Posted at 08:25h, 19 November

    Are these ready for sale?

    I would like to order one

  • fluidmotorunion
    Posted at 14:23h, 11 December

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