SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/dad-coolant-hot-cap

Why never open a radiator cap on a hot engine?

Hot coolant can spray out and burn you.

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  1. The cap breaks if it is cooler
  2. The engine stops running
  3. Hot coolant can spray out and burn you ✔

Why: A Kia manual says never attempt to remove the radiator cap while the engine is operating or hot. Wait until it cools down.

Huh, didn't know that: That manual also says the coolant should sit between the F (Full) and L (Low) marks on the reservoir.

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How come the stadium got hot after the game? Because all of the fans left.
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References

Answer: Hot coolant can spray out and burn you. A Kia manual says never attempt to remove the radiator cap while the engine is operating or hot. Wait until it cools down.

  1. Kia Owner's Manual: Checking the Coolant Level ownersmanual.kia.com/docview/webhelp/doc/cd29e042-ef2c-442e-89a5-061c4e726c68/topics/chapter8_7_1.html
    Never attempt to remove the radiator cap whilst the engine is operating or hot.
    Checked 2026-10-10.

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