I've got some wiring running through that little pop-off hole on the passenger side firewall and when it rains it gets really wet around there. Any recommendations on what to use to close this up? Will regular caulk stick and hold? I can't find the plug that used to be in there but even if I did and cut a slit in it, it would still probably leak.. I want it totally sealed.

 

regular caulk should work... if you have doubts find some thats water resistant/proof....

 

Silicon sealant. 100% waterproof. I use it all the time to seal up metal chase flashings.

 

Cool just making sure, thanks.

 

if u cut a slit down the middle it wont leak thats how i have my wiring running into the car from the engine bay and it has never leaked. give that a try before ghetto rigging it with caulk