How to stop a windshield crack from spreading
Keep the cabin and the glass at a steady temperature — avoid blasting the defroster on a frozen windshield or washing hot glass with cold water — keep the crack dry and clean, avoid slamming doors, and get it repaired within a day or two. Tape over the break is a stopgap to keep dirt out, not a fix.
Why cracks run
Yes. Moisture inside the break freezes and expands overnight, and the swing between a warm cabin and sub-freezing glass stresses the area around the crack. In Michigan, Indiana and Illinois the first hard freeze is when stable chips turn into running cracks.
Avoid it. Water pressure and the temperature swing inside a car wash are exactly what makes a crack run. Hand-wash around the damage until it is repaired or replaced.
When it can still be repaired
Single cracks up to 6 inches long can typically be repaired, provided they have not reached the edge of the glass, are not branching, and are outside the driver's primary viewing area. Cracks longer than 6 inches, edge cracks, or cracks in the driver's line of sight generally require full windshield replacement. Our technician assesses the crack on-site and advises you honestly.
How long you can drive on it
There is no safe number of days. A crack only gets longer, repair stops being possible once it passes about six inches or reaches the edge, and replacement costs more than repair. Treat it as this week's job, not this month's.
Whether it is legal to drive on depends on your state — see the Michigan, Indiana and Illinois rules.
Questions about stopping a crack
How do I stop a windshield crack from spreading?
Keep the cabin and the glass at a steady temperature — avoid blasting the defroster on a frozen windshield or washing hot glass with cold water — keep the crack dry and clean, avoid slamming doors, and get it repaired within a day or two. Tape over the break is a stopgap to keep dirt out, not a fix.
Does cold weather make a windshield crack spread?
Yes. Moisture inside the break freezes and expands overnight, and the swing between a warm cabin and sub-freezing glass stresses the area around the crack. In Michigan, Indiana and Illinois the first hard freeze is when stable chips turn into running cracks.
Can I go through a car wash with a cracked windshield?
Avoid it. Water pressure and the temperature swing inside a car wash are exactly what makes a crack run. Hand-wash around the damage until it is repaired or replaced.
How long can I drive on a cracked windshield?
There is no safe number of days. A crack only gets longer, repair stops being possible once it passes about six inches or reaches the edge, and replacement costs more than repair. Treat it as this week's job, not this month's.
Got a crack that is spreading?
Call us or book a repair — resin injection stops the spread in under 30 minutes.