Can you help me with this challenge. I noticed oil in my CLK 350 coolant just a week after an oil change. How do I determine if there's a leak somewhere or the oil change guys erroneously poured oil into it?

  • Welcome! We need a lot more information from you, please. Can you give us more information about the vehicle this happened with? Year/make/model/engine. Jan 5, 2017 at 17:34
  • 2006/Mercedes/clk350/V6
    – Dika
    Jan 5, 2017 at 17:36
  • Did you look at the oil right after the oil change, or was the oil check a week after the first one you did since the change? How many miles on the car btw?
    – cdunn
    Jan 5, 2017 at 17:39
  • I checked a week after because the oil check light came up. I probably put about 1000miles after the change. What's the temporary solution so I don't mess anything up.
    – Dika
    Jan 5, 2017 at 17:51

1 Answer 1


There are several things you need to do now:

  • Get the radiator flushed and coolant changed immediately.
  • Check the oil level in the vehicle. Ensure it looks as though you'd expect it to look (dark brown) and not chocolate milk colored.
  • Once the radiator is flushed (completely) and new coolant in place, drive it sparingly and check the coolant often to see if oil comes back into the coolant. Often means three or four times a day. If you detect any major amount of oil in your coolant, you have bigger problems ... namely, something in your oil system has sprung a leak and is contaminating your coolant. You'll have to have it checked at this point to see what the problem may be, but it could be anything from a cracked oil cooler to a cracked engine block.

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