Installing a CRL T-Vent window in your Ford Transit’s sliding door is one of the best upgrades you can make for ventilation and factory-style aesthetics. This comprehensive guide walks you through each step of the process—from unpacking and inspecting the window, to creating a precise template, cutting the sheet metal, and installing the window using tapped holes for a secure and flexible mount.
Whether you’re outfitting a full camper van build or just want more airflow, here’s everything you need to know.
Tools & Supplies You’ll Need
| Item | Purpose |
|---|---|
| Trim Ring (from CRL kit) | Used to clamp window to van wall |
| Razor Blade | Cutting tight, accurate templates |
| Cardboard | Creating the window cut-out template |
| Jigsaw with Fine-Tooth Metal Blade | Cutting through sheet metal |
| Grinder + Flap Disc | Removing structural ribs and cleaning up edges |
| Drill + Tap Set (M4 x 0.70) | Prepping screw holes for socket cap screws |
| Socket Head Cap Screws | Stronger alternative to CRL-supplied screws |
| Rustoleum Matte Black Paint | Seals and protects exposed metal |
| Masking Tape | Holds template in place; helps mark locations cleanly |
| PPE (Gloves, Safety Glasses, Mask) | Protects from fine aluminum dust during cutting |
Step 1: Inspect the Window Out of the Box
Before anything else, check the CRL T-Vent window for damage or misalignment. Some units arrive with poor frame spacing that can cause sealing issues later. Look closely at the window radius, corners, and check if the window closes and seals correctly.
If you notice irregular gaps when the window is closed, return it immediately and request a replacement.
Step 2: Trim Ring & Template Alignment
The trim ring included in the kit is not a perfect template—it’s just for clamping the window. However, it’s a good starting point.
- Trace the inner edge of the trim ring tightly on cardboard.
- Cut out your template precisely, trimming excess material so the template matches the window’s outer seal line—not the full trim ring.
- Dry fit the template on the van’s sliding door and mark where structural ribs interfere.
✅ Tip: Make sure to avoid cutting through the door’s locking pin or any electrical components.
Step 3: Align and Tape the Template
- Tape the template to the interior side of the sliding door.
- Measure to ensure even spacing—use measurements like:
- 1.5″ from bottom edge
- 1.75″ from top edge
- 2.25″ from the front edge of the window opening
- Drill four small reference holes (top, bottom, left, right) through the van wall to transfer template position to the outside.
Step 4: Cut the Window Hole
- Transfer your template to the outside of the van using your reference holes.
- Drill a jigsaw starting hole and cut carefully along your traced outline.
- Stick to your marker line exactly for the best fit.
- Cut conservatively—you can always widen the hole later.
- Use a grinder to remove structural ribs where necessary.
- Clean and sand the cut edges, then apply rust-preventive paint.
Step 5: Drill and Tap Mounting Holes
Instead of using the screws CRL provides, tap the van sheet metal for stronger mounting:
- Use an M4 x 0.70 tap to thread the metal around the window hole.
- Install socket head cap screws for a secure, removable fit.
- Add Loctite to screws for extra vibration resistance.
🔧 Tapping the holes allows for easier future removal if the window breaks or needs to be taken off for a vinyl wrap.
Step 6: Install the Window
- Place the window in the hole and ensure a flush fit around all edges.
- Begin tightening screws from the center outward to ensure even compression.
- Watch for curves in the Ford Transit door that may give the illusion of uneven mounting. These are normal and will pull in when the window is clamped down.
- Check the T-vent side (the sliding portion) for evenness and proper operation.
Final Thoughts
The CRL T-Vent window installation can seem daunting, but when done right, it transforms your van’s function and appearance. The key is patience and precision with your template and cuts. Avoid overcutting, use the right tools, and always test-fit multiple times before final installation.
If you’re installing a T-Vent window on your Ford Transit, this guide should help you nail it the first time. Got questions about the process? Drop them in the comments or check out our template-cutting video tutorial.
Ready to take your van build to the next level? Follow along with more in-depth installation guides at VanBuilderHQ.com or subscribe to our YouTube channel for new van life build videos every week.
