I’m sure this isn’t a Honda specific issue, but I figured I’d try here. I have a 2007 Honda element and a few days ago noticed some white smoke coming from under the hood on the passenger side. I brought it to Valvoline because they had just changed my oil 6 days prior. They pointed out the hole in my reservoir cap, but told me it wasn’t the problem, but that my radiator fluid was empty. Neither of which were mentioned or noted at my visit 6 days earlier, and they had no answer as to why that was, only that it must have just happened. So they refilled my coolant, and as I drove a 10 minute drive to an auto parts store to replace my cap smoke started again before arriving. At the auto parts store they said, the cap was the problem, sold me a new one and I thought problem solved. But then 2 days later after very minimal driving my new cap looked exactly the same as the old one.
First picture is my original cap, second picture is the brand new cap after 2 days.
TLDR: Engine coolant reservoir fluid cap had a hole (1st pic)car had white smoke, brand new cap looked exactly the same after 2 days with little driving. Honda Element 2007. I’m not sure if it’s relevant, but had an oil change 10 days prior and had no problems before that