Heads up, Nissan owners! That giant piece of glass above your head may soon be on its way down in a thousand little pieces. Lawsuits accuse Nissan of using a faulty tempering process for their sunroofs since 2008.

These days it’s hard to find a car without a sunroof, so it’s no surprise that there’s more complaints about sunroofs than ever before. While sunroofs will rattle and leak just like any other window, what’s truly concerning is reports of them randomly exploding.

Most exploding reports are about larger sunroofs, such as Nissan’s panoramic sunroof which is an upgrade feature. This expansive piece of glass sounds really nice in marketing and looks great on a test drive, but there’s a problem.

Glass is heavy → large pieces of glass are really heavy → really heavy can affect MPGs → MPGs are king. So to offer a panoramic sunroof, Nissan has resorted to using thinner glass.

Tempering Expectations

Like side and rear windows, sunroof glass is tempered. Tempering is a process of rapid heating and cooling that strengthens the glass and creates a safer break pattern. If tempered glass breaks, you get small chunks rather than life-ending shards.

Tempering is a tricky process and particularly difficult on thin glass. There’s reason to believe that automakers haven’t perfected their tempering process.

Exploding sunroof lawsuit says Nissan’s tempering is flawed

A 2017 lawsuit filed in a California court says all 2008–present Nissan and Infiniti models are at risk of their sunroofs exploding because of Nissan’s flawed tempering.

[The plaintiff] lays out the case about how the tempered glass is heated and then rapidly cooled, creating an outer layer of compression shrink-wrapped around the middle of the glass that is constantly pressing outwards. The tempering creates a stronger piece of glass compared to non-tempered glazing, but the glass can explode without warning if the compressed layer is compromised.

When CarComplaints.com asked four top university engineering professors what makes sunroofs explode, they said that imperfections in tempered glass will cause it to shatter under pressure.

Considering cars are more airtight than ever, the pressure is on.

Reports of Nissan Sunroof Problems

The “Rock Fell on it Excuse”

Automakers like to blame sunroof explosions on owners or random rocks (that somehow shatter the glass from inside). Here’s one reason they’re wrong.