Doghouse insulation

You also want to find and plug any gaps in the firewall that will allow noise and heat to come in while driving. I found that the best way to locate these gaps is to use a strong light on the inside of the coach while you look for gaps under the hood at night. Closing all of these up, along with plenty of insulation on the doghouse cover, will make a huge difference. If you are still bothered by heat, they make an insulation that wraps around your exhaust pipes that also helps to keep the heat out of your engine bay.