Hi there,

Relatively new to 914's and I'm discovering things each time I drive my car. I finally used the rear trunk and stored a back pack in there while I went for a drive. When I got home I popped the trunk open, retrieved my back, and was surprised at how how warm it was.

Is it normal for the rear trunk (carpet / metal) to heat up?

In a word, "Yes"...it is normal. The only other caveat I can think of if it is really hot is if someone has removed the heat shield which resides under your trunk, directly above your muffler....very unlikely....but you can pop your head under a take a look.

In addition to the muffler heat shield, an insulation pad was provided for the floor of the rear trunk under the fitted carpet. On my 76 this was a vinyl covered soft flexible pad (I assume foam or fiber of some sort) between 1/2" to 1" thick. I don't know if previous year cars had this or not.

Insulation like this doesn't stop the transfer of heat, it only slows it. So, for short periods of time it will help keep the rear trunk cool. But from my experience, on long drives, the trunk contents still become warm. The rear trunk is an enclosed space with no means for heat to escape. Given enough time, it will eventually reach the temperature of the ambient air below the trunk floor. That air is tempered by the out side air, engine cooling air, hot engine/tranny air, exhaust system air, etc. In other words, plenty of heat.

My 1973 and 1974 both have the same foam cut out, pretty sure both are original.

Mine runs quite cool, but anything I put in the trunk gets warm eventually. Even on a short trip to the grocery, I don't put anything that needs to be cool in the trunk. With my guitar I will only go a block or two with it in the trunk. Way too warm even with my car and the original insulator on both sides.