Auto mechanics know that there's always a place for RTV silicone sealant in the toolbox. One popular use of silicone sealant on cars is to repair headlights.

Read on to see how you can use silicone headlight sealant.

Silicone Sealant Can Repair Cracked Headlights

When your headlight assembly is cracked, it allows water to build up inside. This water will cause the headlight bulb to blow as soon as it heats up. It’s illegal to drive without both headlights working in all 50 states, so it’s important to address cracked headlights quickly when you notice them.

As long as the headlight is cracked and not busted out, you can repair the crack with RTV silicone sealant.

How to Fix Cracked Headlights with Silicone Headlight Sealant

To fix a cracked headlight with silicone, you'll need:

• Your favorite car washing supplies
• Car polish
• Masking tape
• A good-quality 100% RTV silicone sealant

Here’s what to do once you have gathered all of your supplies:

1. Wash the headlight carefully with soap and hot water. Be careful not to scratch the surface with any grit. Dry completely.
2. Use a small bit of car polish to smooth and shine the surface of the headlight. Pay special attention to the area of, and around, the cracks. This step is important because it ensures a hard, even surface for the silicone to bond to.
3. Use masking tape to tape around the area you'll apply the silicone over. Take your time with this, and neatly tape around details, contours, and along the cracks.
4. Lay a fine bead of silicone sealant over each crack, inside the tape.
5. Mist the silicone with a light spray of regular window cleaner. Use your finger or a damp sponge or paper towel to smooth the silicone out flat over the cracks. Allow to cure in a dry area for a few hours, at least.
6. Remove the masking tape. Polish the repaired headlight again. Then, as an extra precaution, wax the headlight and buff it to a high shine.

These repair jobs often use just a small amount of product, leaving plenty of product leftover for your next project that needs a high-temp sealant.

How to Reseal Headlights with Silicone Headlight Glue

A common issue for headlights is that they build up moisture on the inside. If you suspect leaky headlights, look for a fog or mist buildup inside. Droplets may also run down the inner side of the headlight, making puddles inside the headlight.

The villain of this situation is the headlights' original factory seal, which will crack and leak as it ages. To fix this problem, you could replace the entire assembly, but it's not always necessary. Instead of replacing the entire headlight, you might be able to just replace the seals.

How to Reseal Headlights with Silicone Headlight Glue

To reseal headlights, you'll need:

• A heat source
• Rubbing alcohol
• A scraping tool
• Sandpaper
• Good-quality high-temperature silicone sealant

Remove the headlights from the vehicle, then follow these steps to reseal it.

1. Heat the factory seal until you can begin to separate the pieces of the headlight from each other with a screwdriver. Remove the old seal.
2. Clean the channel where the seal goes completely. Use a scraping tool and sandpaper to remove any residual seal or foreign matter.
3. Pour a glug of rubbing alcohol into the front piece of the headlight (where water has been condensing) and swish it all over the inner surface. Pour the watery alcohol out, and clean the headlight if you can. The alcohol will evaporate, preventing fogging in the future.
4. Lay a bead of high-temp silicone headlight glue in the seal channel. Press the halves of the headlight back together and wipe away any excess silicone with a wet paper towel. Because RTV silicone sealant cures at room temperature, there’s no need to apply heat or other substances to make it cure. Simply let it cure for several hours, ideally overnight.

Silicone sealant is a great choice for resealing headlights because it adheres so well to glass, plastic, and metal. It will cure into a flexible seal that will withstand years of road weathering. If you have any questions about what silicone sealant is best for your next project, give us a call at 812-824-8000. Our team of silicone sealant experts will be happy to help.

Turn to Silicone Depot for Headlight Sealant

We work hard to bring you top-shelf silicone sealants that always stick and seal the first time, are low-odor, and smooth textured for easy application. Stock your shop with Silicone Depot automotive products that always get the job done.