Auto Glass Questions, Answered

Laminated glass is two layers of glass bonded to a plastic interlayer; when it cracks, it stays in one piece, which is why windshields use it. Tempered glass is heat-treated and, as glass maker Pilkington puts it, shatters into very small pieces rather than sharp shards. Most side and rear windows are tempered, though laminated side glass is becoming more common.

The ROLAGS repair standard describes a bullseye as a separated cone in the outer layer of glass that shows as a dark circle with an impact point. It is one of the easiest breaks to repair: the standard allows repair of a bullseye up to one inch in diameter, the size of a US quarter.

ROLAGS defines a combination break as damage with more than one characteristic, such as a star inside a bullseye, or cracks running out from the impact. It can be repaired if the body of the break, not counting the legs, is no more than two inches across and the other repair limits are met.

In the ROLAGS standard, an edge crack is any crack that reaches an edge of the glass, and a floater crack is one that does not. The standard's size limits apply to both. Edge cracks can still be repaired in some cases, but the standard rules out edge cracks that intersect more than one edge.

Hold a coin next to it. A US quarter is just under one inch across, which is the ROLAGS repair limit for a bullseye and for most damage in front of the driver. For a crack, measure its length with a tape and note whether it reaches an edge. Photos from outside, with the coin in frame, help the first call.

A chipped windshield already has a weak point. Blasting hot defroster air onto cold glass, or scraping hard over the chip, adds stress right at that spot, and the chip can run into a crack. Start the defroster on a low setting, let the glass warm gradually, scrape around a chip rather than over it, and never pour hot water on frozen glass.

Try not to until the chip is repaired. Washer fluid and road spray can seep into an open break, and the ROLAGS standard says damage contaminated with impurities that cannot be cleaned out should not be repaired. A piece of clear tape over the chip keeps fluid out while you arrange a repair.

An acoustic windshield has a sound-damping interlayer in the laminate. Glass maker Pilkington describes it as a specially formulated interlayer that reduces outside noise, and Fuyao says its damping layer can cut noise by 5 to 10 dB. If your car has one, the replacement should too, or the cabin may be noticeably louder. The corner print often says acoustic.

It is a band of fine heating wires built into the lower part of the windshield, where the wipers rest, to free frozen wiper blades. Glass maker Fuyao also makes glass that heats the rain-sensor and camera area. Because the wires are inside the glass, a heated windshield is a different part from an unheated one; give the VIN.

Call, describe the car and the damage, and one of our local auto glass professionals will take it from there. Your technician quotes the price, books the time and goes over the glass, any calibration and the worksite with you. The VIN and the damage location help when you call.

Your technician sets the price after learning the vehicle, the VIN, the glass and whether a camera needs calibrating, and confirms it with you before any work starts. Ask for the quote to list the glass maker, moldings and calibration, and compare it with the dated planning ranges in the cost guide.

Yes. The town guides include nine Lake County, Indiana towns, from Hammond and Munster to St. John, and the same line takes those calls. Give the exact address and ZIP with the vehicle details. Our Illinois law and insurance pages describe Illinois rules; Indiana drivers should check their own policy and state law.

The old glass may have carried the vehicle maker's logo, while the new one carries the glass maker's own mark. Both must meet the same federal glazing standard and show an AS1 and DOT code mark. If you expected glass from the vehicle maker, check the quote or invoice, which should name the glass.

Check the lease first. Some leases require repairs with the vehicle maker's parts, and the leasing company may inspect the glass when the car is returned. Ask the leasing company what it accepts, then tell your technician so the quote covers the right glass. Keep the invoice showing the glass maker with your lease paperwork.

Signs include a head-up display showing a double image, a rain sensor or camera that will not seat, a missing heated area, or a different tint band. Tell your technician straight away, before driving far. A part that does not match the VIN's features is an installation problem for your technician to put right.

Usually. The installer covers the dashboard, moves or removes the rear-view mirror and any sensor or camera cover, and may need to open the doors and lower the windows. For a door window, the inside door panel comes off. Leave the keys available and clear the dashboard before the appointment.

A sunroof panel is vehicle-specific and may be tempered or laminated depending on the model. It is usually replaced as a panel rather than repaired, and the job can involve the sunroof frame, seals and drains. Give the VIN and describe whether the sunroof still opens, and whether rain is getting in.

Yes, but film does not transfer. Film on a door or back window stays on the old glass, so the new pane needs new film from a tint installer. On the windshield, Illinois section 12-503 only allows nonreflective film along the top, no more than 6 inches down, so a full windshield film is not an option in Illinois.

Glass features often follow the trim. A base model and a higher trim of the same car can differ in rain sensors, camera-based safety systems, heated wiper areas, acoustic glass and head-up displays, and each can mean a different windshield. The trim narrows the list quickly; the VIN confirms it.

Keep the invoice naming the glass maker and part, the drive-away time you were given, any calibration result, and the insurance claim number if you claimed. The AGRSS installation standard requires installers to keep replacement and calibration records for at least three years, but your own copy is quicker to find if a leak or warning light appears.