Boiling coolant out of the overflow tank?

Tiny
BMXFROG
  • MEMBER
  • 1997 HONDA DEL SOL
  • 2.0L
  • 4 CYL
  • 2WD
  • MANUAL
  • 136,000 MILES
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.
Thursday, September 25th, 2025 AT 4:50 PM

2 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
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.
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Friday, September 26th, 2025 AT 9:49 AM
Tiny
KRAKENAUTO
  • MECHANIC
  • 69 POSTS
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.
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Sunday, September 28th, 2025 AT 5:48 AM

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