I'm right in the middle of rebuilding the LARGE Hybrid battery in a Prius, and needed a break, so checked my emails and saw your message. That reminded me to check my cap again. When I pulled it out and felt around, it was a little sticky on the cap and fill tube. I wiped both surfaces clean with a rag, then sprayed them both with a little WD-40 and Voila, it works perfectly again!


Thank you for the reminder.

 

I just posted on this, guess I should've trolled a bit. Year old cap and it failed. Next time I'll try cleaning and WD-40 on it. I suppose at $10 a pop per year, I'll put up with it.