Boiling coolant out of the overflow tank?

1997 HONDA DEL SOL
136,000 MILES • 2.0L • 4 CYL • 2WD • MANUAL
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BMXFROG
I have a boiling coolant issue. The temp needle does not go above operating temp despite coolant boiling out of the overflow tank.

I have replaced the rad cap, water pump, overflow tank cap, and thermostat. Initially the car did not have a thermostat in it. It was cut out/removed. A complete thermostat was now installed.

I have had this car for close to three years and I never had a problem until about a month ago.
Sep 25, 2025 at 4:50 PM
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STRAILER
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  • 54,494 POSTS
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To me is sounds like you have a blown head gasket, I would follow this video to help confirm the issue:

https://www.youtube.com/watch?v=5zpNjYmmiYY

Please go over this guide and get back to us.
Sep 26, 2025 at 9:49 AM
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KRAKENAUTO
  • ✓ASE Certified Mechanic
  • 40 POSTS
  • ASE Certified Mechanic
What lead you to replace the radiator cap, thermostat and water pump initially? This will help me better assist so I know if this was occurring before you replaced these parts.
Sep 28, 2025 at 5:48 AM
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