Need preventive maintenance tips

[dmarty]

I wouldn’t plug the rocker holes. They’re there for a reason. I can’t say that I’ve cut apart a late model GM pickup lately so I don’t know for sure, but I’ve seen it on many other cars and trucks. The rocker holes not only drain any water that may find its way into the rocker, but they are also connected to the air plenum at the base of the windshield that feeds air to the HVAC system. Some of the air is directed down through the cowl and into the fronts of the rockers. The holes in the rockers let the air flow through and hopefully dry out any moisture.