So which one is right for what year? I am cleaning out stuff and I notice three different types of caps. Version one has small writing and is vented. Version two is the same as version one but NOT vented. Version 3 has a completely different exterior BUT is vented. I know that the non vented caps go with the VENTED reservoir so the excess will flow out the overflow tube. I am guessing there might be another version or two out there.