HPS High Temperature Reinforced Silicone Coolant Bypass Caps, Black/Blue/Red

The silicone cap was a forever solution to replacing a thirty four year old unreinforced rubber cap on my NA6 Miata. Since I was doing a water pump and timing belt, the alternator was off the engine, providing easy access. I Will continue to spread the word on this solution on social media. Thanks for this!

They are very nice quality and fit. I didn't know these existed till I went looking. I have used the rubber caps and they don't last.

Perfect for not doing a hose with a plug. No extra weight vibrating on the end of the hose nipple for cooolant. Works perfect.