Buy BMW 328i Mirror Glass

Overview

The mirror glass-also called side-mirror glass, wing-mirror lens, or door-mirror pane-on a BMW 328i lets you see cars, bikes, and curbs beside your sedan. BMW used different chassis codes (E90/E91/E92/E93 for 2006-2013 and F30 for 2012-2016), but every 328i relies on this small sheet of tempered safety glass to meet U.S. rear-visibility law FMVSS 111 (Legal Information Institute). The glass may be flat on the driver side and slightly convex on the passenger side to widen the view while keeping distances honest (Bimmerpost, apexspeed.com). Many versions add electric heating, auto-dimming, or "auto-dip" tilting when you shift into reverse (Dealer E Process, BMW Discover, E90Post). Tempered glass is about four times stronger than normal glass, so when it finally cracks you usually replace only the pane, not the whole mirror assembly (hawkeyewindows.com, Wikipedia).

Fitment Guide

BMW 328i models that can accept a clip-on or adhesive replacement pane include:

• E90 Sedan (2006-2011), E91 Wagon (2006-2012), E92 Coupe (2007-2013), E93 Convertible (2007-2013) (Wikipedia)
• F30 Sedan (2012-2016)-check for square-corner or rounded-corner glass shape before ordering.

Always match the options listed on your build sheet: heat, auto-dimming, blind-spot line, or lane-change warning icon.

Key Features

Heating

A thin resistive layer warms the glass whenever the rear-defrost circuit or an outside-temperature sensor (≈ 37 °F/3 °C) triggers it (E90Post, YouTube).

Auto-Dimming

A light sensor in the interior mirror sends a signal; an electro-chromic layer on the driver-side glass darkens to cut headlight glare at night (Bimmerpost, M3Post).

Auto-Dip (Reverse Tilt)

With mirror toggle set to "R," the passenger mirror tilts down to show the curb when you select reverse, then returns when you drive forward (BMW Discover).

Flat vs. Convex

Flat glass gives an undistorted view on the driver side; convex or "wide-angle" glass on the passenger side stretches the field by ~25 % but makes objects look farther away (Acko, apexspeed.com).

Safety Rating

All mirror panes must be tempered safety glass that shatters into small cubes, satisfying FMVSS 111 impact tests (NHTSA, Wikipedia).

Failure Signs

• Hairline cracks or chips that spread when you close the door.
• Brown spots or "ghost" patches where the heating layer burned out.
• Blurry yellow edge-electro-chromic fluid leakage.
• Loose vibration or rattling after a minor scrape.

Quick Replacement Steps

1. Protect the painted cover with masking tape.
2. Tilt the mirror fully inward.
3. Insert a plastic trim tool under the outer edge and pop the old pane free.
4. Unplug heater/auto-dim wires.
5. Clean the backing plate with isopropyl alcohol.
6. If your new pane has no clips, spread a thin, even layer of an epoxy made for automotive mirrors-many owners use a two-part gel such as Loctite Epoxy (loctiteproducts.com).
7. Press the new glass evenly for 30 seconds; support it with painter's tape until the adhesive cures (often 1-2 hours) (Reddit).

Tip: work above a towel so falling shards don't scratch plastic trim.

Care & Maintenance

• Defog faster. Turn on rear defrost early; the mirror heating circuits share that switch (Dealer E Process).
• Clean gently. Use glass-safe wipes; ammonia cleaners can stain the electro-chromic layer.
• Fold manually in icy weather. Power-fold motors can jam if ice glues the glass to the housing.
• Inspect yearly. Look for edge corrosion on the silver backing; surface pitting scatters light at night.

Frequently Asked Questions

Q: Why is only the driver's-side pane auto-dimming?
A: BMW links the dimming sensor to the interior mirror and darkens only the driver side on many models; the passenger pane stays clear for sharper distance judgment (Reddit).

Q: How do I know if my glass is heated?
A: Look for two small push-on connectors behind the pane. You can also watch for melting frost after you turn on rear defrost (E90Post, YouTube).

Q: Does convex glass pass U.S. safety rules?
A: Yes. FMVSS 111 allows convex passenger mirrors as long as they display the etched warning "Objects in mirror are closer than they appear" (Legal Information Institute).

Q: My glass looks blue-normal?
A: A blue-gray tint is the electro-chromic layer that darkens at night; minor color shift is normal (M3Post).

Q: Can I glue new glass over cracked glass?
A: No. The old shards can loosen and fall; always remove damaged glass first (loctiteproducts.com, Reddit).

Q: What adhesive works best?
A: Two-part epoxies or mirror-specific urethanes rated for exterior use bond plastic backing plates and glass well (ZDS Adhesive).

Q: Why is my driver mirror flat while the passenger one is curved?
A: Regulations favor accurate distance on the driver side, but allow a wider field on the passenger side to reduce blind spots (apexspeed.com, Acko).

Q: What is tempered glass?
A: It is heat-treated glass roughly four times stronger than regular glass; when it breaks it crumbles into safer cubes instead of sharp shards (hawkeyewindows.com, Wikipedia).

Q: Do heated mirrors draw a lot of power?
A: Only a few amps; they shut off automatically when the cabin sensor sees the glass is clear or the timer ends (Dealer E Process).

Q: Can I retrofit auto-dimming glass?
A: Yes, but you must run two extra wires for power and a control line from the interior mirror; coding may be needed on newer F-series cars (E90Post, Bimmerpost).

Q: What's the "auto-dip" feature?
A: When the mirror selector switch is set to the right, shifting into reverse tilts the passenger mirror down to show the curb, then restores the normal angle when you drive forward (BMW Discover).

Q: Does mirror glass have a service life?
A: Tempered panes can last decades, but hard water spots, scratches, or silvering corrosion may make replacement worthwhile after 10-15 years.

Q: How can I prevent cracks?
A: Avoid slamming doors and scrape ice gently instead of hitting the glass. Tempered glass is tough but not unbreakable.

Q: Is special coding needed after glass swap?
A: No coding is necessary unless you change to an option your car did not originally have, such as adding auto-dimming glass.

Q: Are aftermarket blind-spot stick-ons safe?
A: They are legal when they don't block the required mirror area, but choose optical-grade glass to avoid distortion (Acko).

Q: Why does my mirror fog on humid mornings?
A: Even tempered glass cools quickly; turn on rear defrost so the heater element dries the surface.

Q: What if the heater stops working?
A: Check the mirror fuse and look for broken heater lines on the back of the pane before replacing the whole mirror (YouTube, E90Post).

Related Topics

• Blind-Spot Line: European-spec split mirrors use a vertical dotted line to combine flat and convex zones.
• Mirror Caps: If the mirror housing is scuffed, the painted cap can be unclipped without touching the glass.
• Cameras & Sensors: Some later F30 mirrors carry surround-view cameras; replacing those requires extra care with wiring.
• Coding Tools: Apps like BimmerCode let owners activate mirror tilting or folding via the OBD port (always back up your coding first).

Regular inspection and fast, careful replacement keep your BMW 328i mirror glass-and your view of the road-clear and safe.