Could also be something as simple as a radiator cap.
Reviews of OEM Honda radiator cap
6 votes
2 reviews
Honda Radiator Cap 19045-PAA-A01. Accept no substitutions. Those aftermarket-OEM (Murray or whatever from O'Reilly's and Autozone) are JUNK. I've had several. I'm now on my second HONDA one, not due to design flaw but due to driving my car with a breeched head gasket for 3 years. The parts house ones NEVER lasted nearly as long (only about ten stops or so for me).
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