I accidentally put antifreeze in the engine oil, a complete moment of stupidity, but I poured about 50ml (definitely not more than 100ml) do you think it would be okay as it’s such a little amount?

Or will I need to drain this.

  • Welcome to Motor Vehicle Maintenance & Repair! Nov 4, 2021 at 21:59

1 Answer 1


You poured antifreeze into your oil gallery ... you need to drain and fill will fresh oil. If you haven't ran it, you can possibly put the vehicle on level ground then pop your oil drain plug out for a short period of time, but long enough to drain the coolant out of it. You will drain some of the oil in the process, so be prepared to add some back in to top it off. This still won't get all of the antifreeze out, but it should be okay with trace amounts. Don't be surprised if the oil still gets a little milky. If it does, it'll need to be changed, because when the oil and antifreeze mixes, it becomes acidic and can damage the soft metals of the engine.

  • Oil is cheap compared to engine rebuilds. If this were mine, I'd drain and replace the oil rather than risk running contaminated oil.
    – jwh20
    Nov 4, 2021 at 22:38
  • @jwh20 - That's what I'd do as well, which is why I lead with it in my answer. Nov 4, 2021 at 22:48

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