Also, be aware that a lot of owners remove the cabin heat scat hose from the muff to the firewall during the summer. This reduces the blast of hot air on the flapper box and firewall. Since some flapper boxes leak, this keeps the cabin cooler in the summer.
I was told, do not remove the hose from the baffle to the muff. The airflow through the muff must continue or the manifold pipe inside the muff will have no airflow and will soften and maybe melt through. Don't forget to reinstall it in the fall. I'm not a mechanic of any kind. Consult on this with your mechanic! Ed
