Replacing Your Vehicle’s Windshield? Here is Your Windshield Replacement Survival Guide.
A vehicles windshield provides the occupants a barrier from road debris and the outside elements. But most people don’t know a windshield is designed for structural safety in case of an accident, especially a rollover. A windshield is a vehicles third most important safety feature behind the seat belts, and air bags.
Windshields are like basketball backboards for air bags. So if you have a damaged windshield your air bag may not function correctly. It actually may inflate out the windshield cavity, rather than towards you. Or it won’t adsorb any pressure because your windshield simply pushes out.
Most consumers are not aware that when technicians replace your windshield, there is significant scratching to the “pinchweld” where the glass bonds to the car. These scratches must be prepped using paint and rust prevention steps. They should not simply leave exposed scratches where moisture from the exterior side can cause rust to develop.
Here are some questions you should ask your auto glass company:
- Is the new glass OEM?
- Did they remove the brand label on the windshield?
- Does the new glass have a shade band that matches your old glass?
- Is the new windshield the same color glass? (glass is actually colored, not clear)
- Does your windshield have a rain sensor?
- Is your windshield heated? (companies will install non-heated and charge for heated)
- Does the windshield have the right bracket for your rear view mirror?
- Does the new windshield have the same third visor as your old glass? (the painted black design which you can see around the rear view mirror on most cars)
- Are they using a universal trim molding, or the actual trim molding part for your vehicle?
- Does the company pay to fix paint scratches, if made by the auto glass technician?
Always inspect a piece of glass for scratches and distortion before it’s installed.
Types of Automotive Glass
A windshield is actually two layers of glass with a laminate material between the layers, what is called “laminated glass”. Laminated glass is extremely hard to puncture or break apart. That’s why a large object like a stunt man, can impact the windshield without breaking through. The strength of laminated glass combined with proper adhesion of the windshield to the body of the car provides massive strength against the roof collapsing in a rollover.
All of the other windows in your vehicle are “tempered glass”, which means they break into tiny fragments to reduce injury to the occupants. (a small fraction of vehicles have laminated side and rear windows also)
Today’s vehicles use urethane as the adhesive to bond the windshield to the vehicle, like a glue. Some urethane after complete hardening which can take 2-4 weeks, can hold 500 pounds per square inch of pressure. That’s one reason why you could never simply push your windshield out. Impossible! Some urethane allows you to drive away within one hour after installing the windshield, hardening just enough to withstand vehicle accidents. When your replacement has been completed, make sure to inspect the inside of your vehicle around the edge of the glass. Make sure no urethane has oozed out into view or onto your vehicles interior. This is more common then people realize and needs to be fixed immediately before the glue hardens!
The urethane is normally heated, then applied to the glass or car body at the raised temperature. Depending on where you live or the application, they can use different kinds of urethane, even a cold temperature apply that is not heated. Temperature has a huge impact on the adhesion qualities of the windshield. I would recommend never getting your windshield replaced in temperatures lower than 55 degrees, or higher than 105 for the best results if possible. This is easy if you have the glass replaced inside of a shop or in a shaded area. Direct sunlight can heat the windshield to over 125 degrees!
Urethane does have an expiration date, so make sure you ask about this before a technician begins replacing your vehicle glass. Using expired urethane means minimal bonding power and the windshield has a chance of coming out during an impact. All urethane is made with an expiration date printed on the tubes, and if they don’t call someone else!
Paint Scratches, Rust, and Proper Windshield Installation
Deep vehicle scratches can turn into major problems later. Moisture will enter through a scratch and attack your vehicles body causing rust later. For people who live by the ocean, this can be disastrous for the structural integrity of your vehicle down the road near the windshield. If you are buying a used vehicle, make sure you check around the edge of the glass and under the trim molding for evidence of rust. Rust will spread under your paint, it is amazingly aggressive.
If the rust spreads to the “pinch weld” which is where the urethane is placed, the urethane will not bond and a windshield will leak or can even be pushed out. This can cause thousands of dollars in damage from water leaks or can even can cause death in an accident! If the rust moves into this area the technician must remove it before applying the urethane, or the vehicle must be sent to a body shop for repair.
Make sure the technician takes steps to prep and repair scratches to the pichweld. There is primer paints, metal rust prep chemicals, and other ways to cover scratches to reduce the appearance or spread of rust. The most important areas are where water will contact your vehicles body, especially under the exterior trim molding. That trim is not water sealed between the body and glass. The water seal comes from the urethane bead.
It is very important that you watch the installation of your vehicle glass if possible, DO NOT just walk away. If a professional technician can not perform the job while you watch, they shouldn’t be working on your vehicle and call someone else. A technician can cause significant paint scratching to your exterior paint job with improper techniques. Some even use nail polish or paint to hide the damage. Some even rub dirt into the scratch to make it look old! Ensure that the technician is using vehicle protective equipment like seat covers, floor mats, tape on the car body where it’s close to the glass, and a protective mat over your hood.
Make sure the technician removes body parts like windshield wiper arms and the cowling (located beneath the wipers) are removed, if the glass edge is covered by these parts. Most technicians will simply shoot a ton of urethane under the cowling area and “stuff” the glass, sliding it into the glue and under the cowling. This is extremely unsafe! A technician doesn’t even know if the urethane has created a proper seal, or if it is bonded safely. A proper windshield installation requires that the glass be place straight down onto the urethane bead. Also this ensures the urethane is not shot all over parts beneath the cowling like wiper assemblies and wiring.
OEM Windshields and OEM Equivalents
OEM means, original equipment manufacturer. So if your vehicle is a Honda Civic, OEM glass would be purchased from a Honda Vehicle Dealer. Auto glass installers can simply order OEM glass from the dealer. Make sure the glass has the OEM label. The windshield label which is about a square inch in size, normally is located in the lower corners of the glass. Sometimes OEM glass says the actual glass manufacturer rather than the Car Dealer name. Call your local dealer on what to look for.
A lot of auto glass companies will tell you they are installing the “OEM Equivalent” part. Because consumers don’t know what to look for, most times a glass with no label or an aftermarket part is used. Do not buy a glass when the label has been etched or removed. No one knows where it came from! Always check the label.
The only scenario in which you may find an equivalent glass, is purchasing a windshield produced by the same manufacturer which produced the OEM glass. It may even be from the same production line and mold from the OEM manufacturing!
Aftermarket Automotive Windshields
Do not be fooled into thinking an aftermarket windshield is the same as an OEM glass. Aftermarket windshields are made using reverse engineering instead of the original OEM mold and production line.
Aftermarket glass tends to have more visible light distortion when viewing the glass at an angle, and the dimensions are not exactly the same as an OEM. All glass that is bent has some level distortion yes, but it is considerably worse with aftermarket manufacturing. You may even see distortion when looking straight through aftermarket glass.
Aftermarket glass is transported through different processes than OEM glass from a dealer. A lot of OEM glass is transported covered by plastic wrapping and using strict shipping techniques, and the windshield’s edges are protected by foam wrapping. But Aftermarket glass is transported by much different practices. Most auto glass companies use no protection covering all surfaces of the glass for transport. And sometimes pieces of glass have been taken to customers locations and returned to the distributor or shop. So aftermarket glass has been handled many times!
Now I’m not saying aftermarket glass is unsafe or unfit to use at all. I’m simply stating the facts about the truth, for your education and insight. I feel you should be educated about this part of your vehicle which essentially protects your family on a regular basis.
Rain Sensors and Other Accessory Plugs Such as Heated Glass
If your vehicle has a rain sensor it should be located near the rear view mirror. A lot of times it looks like a circle, square or triangle. This option allows the windshield wipers to speed up or slow down depending on the amount of rain automatically. Make sure you get the same designed glass. If the rain sensor involves a gel patch, make sure the technician does not leave lots of air bubbles when installing it. Those air bubbles can cause the sensor to malfunction.
Some vehicles like a Land Rover, have plugs located under the interior a-pillar trim. On some convertibles like a newer Ford Thunderbird, a large portion of the interior may need to be diss-assembled to remove the interior a-pillar trim. On the Honda Ridgeline, the heater plug is located behind the glove box. Some new vehicles also have Lane Departure sensors located near the rear view mirror.
You can always find out what you need by calling your local dealer and giving them your VIN Identification number from your vehicle. If your car is important to you and you want to maintain the investment, always call your local dealer and ask for advice about your specific vehicle.
Windshield Shade Bands and Windshield Color
All auto glass has a shaded color. No windshields are completely clear. Typical shading colors are blue, green, bronze, and grey. Be sure sure to get the same color. You will see that all pieces of glass in your vehicle are the same color, excluding privacy glass and tinting.
A windshield may have a shade band across the top near the roof of the vehicle. This area is preferential. You should decide if you like it or not. It does tend to hide the edge of the interiors headliner when looking at the vehicle from the exterior. Shade bands do come in different colors but not all windshields
Most windshields can be ordered without a shade band at all. But you may find the part is actually more expensive because less people order it. Having a shade band does provide some shading in between your sun visors but it does little to drastically shade the sun. Take note the shade band will be darker at night.
Exterior Trim and Moldings
Your vehicle may have exterior trim or moldings cover the edge of the glass and/or covering the edge the car body. If the trim molding is just rubber, make sure you know what the technician is using to replace it. Some companies are now requiring that technicians use only a universal type aftermarket molding, rather than one that is specifically designed for your car. There should also be an OEM molding part available which is exactly the same as your original molding. Do note that cost for OEM is always more.
You may see plastic and/or metal trim moldings covering the edge of your windshield on the exterior. Normally these have some type of plastic or metal clips that attach them to the glass or vehicles body. Make sure the company replaces any broken clips or parts from removal of these parts. If your vehicle is older than 3 years, these parts become very brittle and damage easy. You may be warned about parts that always break, in which the company may request you also purchase that part ahead of time. You may find a lot of companies simply glue those parts back into place, rather than replacing the broken parts.
Vehicle Windshield Logo and VIN Window
On vehicles like a Ford Mustang and Ford F150, you may have a logo in the third visor above the rear view mirror. These windshields can be ordered with out the logo and are cheaper that way. Make sure you ask about your options.
Most windshields have a small narrow window for viewing of the VIN identification number near the lower drivers side portion of the glass. Make sure this window is in the right location on the glass. When the job is completed, make sure that glue has not covered the VIN, the VIN number plate has not been cut off, or that it has not been badly damaged. Police or the DMV will give you a hard time if the number is not legible or is completely missing from that location.
My name is Tim Doyle and I own Auto Glass by O’Doyle, a windshield repair and auto glass replacement company. I have expert automotive experience from working in the auto glass industry for the world’s largest auto glass company and the nations largest auto glass franchise.
A lot of my experience also comes from working in the auto racing industry for over 14 years. I also drive and co-drive for a professional off-road racing team. Visit our website where I provide tips about auto glass questions about any topic related to glass installations, how-to, windshields, door glass, rear glass, rain sensors, rear view mirrors, domestic auto glass, foreign auto glass, door panels, cowls, side mirrors, and more.