I noticed there are multiple holes on the firewall that are allowing the engine heat to come into the cab. At first I thought it was just Sacramento heat but soon realized that it was because of the various holes on the firewall. The holes are different sizes and shapes. Is there plug kit that should be used to prevent the heat from coming in? Or, do I need to get the welder ready? I'd like to keep the cab as cool as possible. Looking for feedback on what the experts here have done to resolve this.. Thanks, sjlafs
If you can get to the inside to clean around each hole and rough that area with course sand paper I would use "Panel Bond". It is stronger than weld, no spatter, doesn't start fires, and won't cause the paint to blister on the outside. Just cut square pieces big enough to cover the holes, "butter" around the edges, press it on and duct tape it in place over night. You can rough the patch and firewall on the engine side and epoxy or bondo it if looks are important. Here's a firewall that had four heaters during it's lifetime (eight heater hose holes) plus all the factory holes; it's been done about ten years now.
You can also get hole plugs from Lowe's in different sizes that pop in the holes. Some holes that are smaller will use small plastic plugs, they may have to be drilled out just a hair. After the hole plugs, cover them with the black strip caulk to sel them. Now use Dynamat or Hushmat.....I like the hushmat, but it is hard to find. Now use some of the Jute backed silver foil stuff and some 3m Super 99 and glue this to the firewall. This is about all you can do for it, but heat will still get in, only a good bit less.
ALL The Above Plus ; You can use RTV to close up the loose old rubber grommets on work trucks . Adding a sheet of Dynamat _really_ helps , as does replacing the gone missing foam seals around the floor pans ans tranny shift tower on four speeds . Keep at each and every tiny hole and you'll be well rewarded , it'll be quieter and cleaner inside the cab too
Take Evan's advise and use panel bond.I wish that I had thought of it.I welded up 54 holes from 1/4'' to 3".You should check out www.fatmat.com,I used their heavy duty product called rattle trap.100 sq.ft. cost $210.00 delivered to your door.I covered the firewall,floor cab back,overhead and inside of doors and had a small amount leftover. Ichecked the temp of the firewall just behind the exhaust manifold,it was 186 degrees,I went inside and checked the same place with my infared thermometer and it was 89 degrees. Then I put a layer of sound deadening foam on the firewall and under the carpet.Hope this info helps.
We just put plugs & putty in the holes in the firewall. It was a vast inprovement in smell and heat. The electrician trade may call this putty live rubber, it's black and stays plyable. I want to use the sound deadner. If anyone has theirs apart Lizard Skin is used around here, it sprays on. Has anyone used the exaust pipe tape for reducing heat?
Exhaust Wrap Yes ; We put it on a few of my son's racecars , it worked well . Supposedly it helps extract the hot exhaust gasses a tiny bit too .
