If you’ve ever gone to open the hood on your ride and felt like you’re trying to hold a hot frying plan, it’s time to look at installing some hood insulation. Old/outdated hood insulation can start to come apart and look pretty grungy when you pop the hood, or in a lot of cases these days vehicles don’t have any hood insulation from the factory.

Hood Insulation Benefits

• Prevents hood from being heated to high temperatures
• Keeps heat from damaging the hood’s paint finish
• Improves the visual look of the hood’s underside

We did some tests in a previous blog with this 2006 Jeep Wrangler LJ (long wheelbase version of the normal TJ) to help protect certain things from the high underhood temperatures that are common with Jeep Wranglers that have the 4.0L inline-six. The 4.0L is an all iron motor and puts out a lot of heat. Combined with the tight confines of the TJ/LJ Wrangler’s engine compartment, it makes for a lot of heat exposure.

From the factory the 1997-2006 had no hood insulation. All the heat radiating upward heats the hood like a frying pan. The surface gets so hot touching it can be painful, not a fun situation when you need to pop the hood when the Jeep is hot. We wanted to see what difference adding some Heatshield Products would do for lowering the hood’s temperature. In this situation there are two options, either Sticky Shield^TM or Lava^TM Shield thermal barrier. Both materials have built-in high-temp adhesive backing that make them ideal for insulating the underside of a hood. Each is also lightweight and fire resistant.

We chose Lava^TM Shield for this test for it’s thinner profile over Sticky Shield^TM (0.008-inch thick versus 1/8-inch) and it’s carbon fiber-like appearance that gives the underside of the hood a much improved look. For our test, we drove the Jeep around in normal traffic until it reached operating temperature. Then we used our contact probe to measure how hot the hood was before and after installing the Lava^TM Shield on the underside.

ABOVE: To take before and after temperature readings we used our direct contact thermal probe placed in the same spot on the hood directly over the engine.

ABOVE: The ambient air temp on the day of our test was 89 degrees on a partly cloudy day. With the Jeep up to full operating temp after a one mile drive in normal traffic, the hood measured 140-degrees F. When the Jeep is hot and the hood has to be opened, it can be a painful experience and burn your hand if you hold the hood too long.

ABOVE: Before installing the Lava^TM Shield material, we thoroughly cleaned the hood of any grease and oil residue. First step we used Simple Green, then used isopropyl alcohol to make sure the surface was clean of anything that would interfere with Lava Shield’s adhesive backing.

ABOVE: Lava^TM Shield is only 0.008-inch thick and very flexible, so it goes around bends easily and shaped to a variety of contours normally found on automotive panels and bulkheads. We used part number 770005 that’s a 48-inch by 60-inch size piece of material. We set it out in the sun while we cleaned the hood to help take some of the curl out from it being in a roll during shipping.

ABOVE: Looking at the hood’s underside, we decided the best install approach was to do it in two pieces. We measured each section of the hood that was going to be covered by Lava^TM Shield.

ABOVE: Using a straight edge we marked on the Lava^TM Shield where to cut.

ABOVE: Another great feature of the Lava^TM Shield material is it cuts easily with a heavy pair of scissors. Especially good when you’re having to cut the material into circular and/or difficult shape.

ABOVE: Lava^TM Shield has a high-temp adhesive backing that will stick to almost any clean, smooth surface. Thanks to its specially formulated volcanic rock-based fibers, it’s chemical- and acid-resistant. It has a maximum constant temperature rating of 1200-degrees F, and only needs a minimum of ½-inch of airspace to work effectively. To make the installation easier, we just peeled back the end of the covering material on the adhesive backing.

ABOVE: We placed the one exposed edge into the right spot, then slowly pulled the backing material off as we progressed across the hood. Similar to how you would install window tinting or vinyl wrap. The Lava^TM Shield installed easily to the hood’s shape/curves.

ABOVE: And here’s the finished result. The underside of the hood looked a lot better now, and the Lava^TM Shield’s 0.008-inch thickness meant it didn’t cause any interference issues when closing the hood.

ABOVE: Once the installation was finished, we drove the Jeep for the same distance and on the same route as we did for the baseline temperature readings. Our efforts were rewarded with a reading of 124.3-degrees F, just under a 16-degree drop in temperature. We also noticed that with the Lava^TM Shield in place, the harmonic resonance of the hood changed, and it seemed to muffle out some of the 4.0L’s audible valvetrain noise for a quieter idle sound.