{"id":1971,"date":"2018-03-07T23:45:55","date_gmt":"2018-03-07T23:45:55","guid":{"rendered":"https:\/\/info.glass.com\/?p=1971"},"modified":"2024-04-03T21:18:42","modified_gmt":"2024-04-04T01:18:42","slug":"case-spontaneous-windshield-breakage","status":"publish","type":"post","link":"https:\/\/www.glass.com\/info\/case-spontaneous-windshield-breakage\/","title":{"rendered":"The Case of the Spontaneous Windshield Breakage"},"content":{"rendered":"

Question regarding spontaneous windshield breakage:<\/h2>\n

Dear Glass Detective,<\/em><\/p>\n

I have a crack that formed on the lower passenger side corner of my windshield. There is a small star pattern with a dominant horizontal crack. The star is centered over a heating element in the windshield<\/a> designed to prevent ice from building up on the windshield wipers. I am looking for an opinion on whether the star pattern necessitates an external trauma? Toyota thinks so, so they won’t replace the windshield<\/a> under warranty. They say the star must mean trauma. No chip present, if so minuscule (less than 1mm diameter and that’s debatable). The star sits under the top half of the wiper blade, which would shield it from road debris (unless the wipers were on). I don’t recall hearing anything impact the windshield while driving. The plane of the wiper bladed coming down on the windshield is about 1\/2cm below the center of the star, so the wiper blade coming down could not have caused the trauma. My hypothesis is that the heating element caused the crack, but I don’t know id a focal area of heat can cause a star pattern. What do you think caused the crack–heat or mystery trauma?<\/em><\/p>\n

Thank you,<\/em><\/p>\n

Micha J.<\/em><\/p>\n

Answer to question regarding spontaneous windshield breakage:<\/h2>\n

Thank you for contacting the Glass Detective regarding your request for some help in determining what may have broken the windshield on your Toyota. I have carefully read and reread your very informative and concise e-mail about the matter and I think I might possibly understand the answer you would most likely want to get \u2026 although what I am about to state may not get you there. With this in mind, here are my responses\/comments to your questions based on 47 years in the glass business and hundreds of personal experiences with a great deal of reading on this subject as well. All comments will be mine and mine alone but you may feel free to share them as you deem appropriate. Here we go:<\/p>\n

    \n
  1. I believe, based on what you have written, that the outer piece of glass (in the windshield) was the only piece to break or was the first to break. Windshields<\/a> are made with two pieces of glass laminated together<\/a> with an inner layer of vinyl (a sandwich if you will with the glass being the bread and the vinyl being the peanut butter in between the two pieces of bread). Feel free to substitute a different food type for the inner material (vinyl) if you\u2019d like. I am just partial to peanut butter.<\/li>\n
  2. If, as we are supposing above, the outer piece broke first, the most likely cause for the breakage was something hitting the outside of the windshield<\/a> with enough force to break it. Often, the inner lite of glass will not break simply because the outer one does.<\/li>\n
  3. Very often the break will start at an origin spot caused by road debris of some sort. A small pebble, a bird, a piece from a tree, or whatever. An innocent looking piece of debris can easily break the outer lite of glass when the car is moving because if you are going 60 miles an hour, the object hitting the glass is getting its force from the car\u2019s speed (at point of impact). Even at low speeds, certain objects can easily break the outer glass in a windshield<\/a>.<\/li>\n
  4. The break process you describe (star pattern that then runs horizontally as a crack) is extremely common. The star is where the glass initially got broken and then opened up and \u201cran\u201d to (usually) the nearest glass edge.<\/li>\n
  5. The heating element may or may not have contributed to the \u201crunning out\u201d of the break. If it was extremely cold and you put the defroster on high, it is possible that the thermal shock or temperature differential accelerated the \u201crun\u201d from the break origin. But in all likelihood, the heat element had nothing to do with the initial break. If so, the inner piece of glass would most likely have broken first and a \u201cstar\u201d would most likely not be present. Thermal cracks usually run out pretty quickly and the origin is typically at an edge \u2026 no star present.<\/li>\n
  6. You may not have heard anything hit the windshield if you had the radio on, wipers going, were talking with another passenger or on your cell phone \u2026 and shame on you if you were on your cell phone.<\/li>\n
  7. Lastly, I can accept and understand the manufacturer\u2019s claim that the break was an \u201cexternal trauma.\u201d This occurs thousands upon thousands of times all over the world every year. I\u2019m sorry but you are now one of those \u201coccurrences\u201d in my opinion.<\/li>\n<\/ol>\n

    Thank you for contacting the Glass Detective<\/a> and I hope the above comments are of some help to you.<\/p>\n","protected":false},"excerpt":{"rendered":"

    Have you been the victim of spontaneous windshield breakage? Then this blog is for you! The Glass Detective explores the possibilities of what might actually cause these chips and cracks that seem to appear out of nowhere. Spoiler alert: There is always an underlying cause. Find out more!<\/p>\n","protected":false},"author":2,"featured_media":865,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"content-type":"","footnotes":""},"categories":[2,1395,1352],"tags":[12],"_links":{"self":[{"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/posts\/1971"}],"collection":[{"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/comments?post=1971"}],"version-history":[{"count":1,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/posts\/1971\/revisions"}],"predecessor-version":[{"id":70348,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/posts\/1971\/revisions\/70348"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/media\/865"}],"wp:attachment":[{"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/media?parent=1971"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/categories?post=1971"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glass.com\/info\/wp-json\/wp\/v2\/tags?post=1971"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}