How to Install a Radiator Fan Shroud
A properly installed fan shroud maximizes airflow efficiency and protects your cooling system under load. Use the section below that matches your radiator type — Cross Flow or Down Flow — to ensure a clean, secure fit every time.
Cross Flow Radiator Fan Shroud Installation
Cross flow radiators route coolant horizontally from one tank to the other (left to right or right to left). The fan shroud mounts to the rear face of the radiator core and must align with the horizontal structural mounting points. Use this video to help measure your cross flow radiator.
What You'll Need
- Blue Masking Tape
- Flathead & Phillips screwdrivers
- Drill and Tap (optional)
- Rivnuts (optional)
- Thread locker (optional, but recommended)
Before You Start
- Allow the engine to cool completely before working near the radiator
- Confirm fitment using your radiator part number and radiator dimensions posted on the shroud listing. If they're missing, contact us.
- Verify the shroud mounting tabs sit flush with the top and bottom "top hat" or flange.
Installation Steps
1. Remove the Radiator (optional, but highly recommended)
Place the radiator flat on a work bench. Be careful as not to dent or bend any of the radiator core fines.
2. Position the new shroud
Place masking tape on the top and bottom mounting areas. Align the shroud mounting tabs with the radiator top and bottom channels. The shroud should sit flush with no gaps between the shroud edge and the radiator face. Trace the mounting holes on the masking tape. Remove shroud.
3. Drill and Tap, or use Rivnuts
Drill and tap, or install rivnuts where you marked the masking tape. If you purchased a Matte Black shroud that includes extra fasteners, they are metric M6x1 threads. For "Top Hat" radiators, the top and bottom rectangular mounting points do NOT have coolant flowing through that area. You can drill through it, without fear.
4. Install shroud flap doors
The rubber flap door nibs need to be installed with the three holes at the top of the door opening, when the shroud is vertical. (Most shrouds can be mounted up, or down, depending on where you want the fans to be located) Insert the rubber nibs into the matching row of holes. Using pliers, pull on the rubber nib, which makes it thinner, and pull gently through the hole. Release and reset the pliers, continue until the flap door is flush with the shroud. To remove the flap door, use pliers to pull on the nib to make it thinner while at the same time pulling the flap door to remove it.
5. Mount the Shroud
Mount the shroud on the radiator. If you used the drill and tap method, we recommend using Blue Threadlocker. Be careful as not to overtighten.
6. Mount the Radiator with Shroud
Mount the radiator and shroud in your car.
7. Mount the fans
Best to mount the fans AFTER the radiator and shroud are in the car. Install each fastener loosely, before tightening all fan mount fasteners. All shrouds have M6x1 threaded holes, unless otherwise specified.
Down Flow Radiator Fan Shroud Installation
Down flow radiators route coolant vertically from the top tank to the bottom tank. The fan shroud mounts to the rear face of the radiator core and must align with the vertical left and right brackets, or tank braces. Use this video to help measure your down flow radiator.
What You'll Need
- Blue Masking Tape
- Flathead & Phillips screwdrivers
- Drill and Tap (optional)
- Rivnuts (optional)
- 3/16" Pop-Rivets (optional)
- Thread locker (optional, but recommended)
Before You Start
- Allow the engine to cool completely before working near the radiator
- Confirm fitment using your radiator part number and radiator dimensions posted on the shroud listing. If they're missing, contact us.
- Verify the shroud mounting tabs sit flush with the left and right brackets or tank braces.
Installation Steps
1. Remove the Radiator (optional, but highly recommended)
Place the radiator flat on a work bench. Be careful as not to dent or bend any of the radiator core fines.
2. Position the new shroud
Place masking tape on the side mounting areas. Align the shroud mounting tabs with the radiator side channels. The shroud should sit flush with no gaps between the shroud edge and the radiator face. Trace the mounting holes on the masking tape. Remove shroud.
3. Drill and Tap, or use Rivnuts
Drill and tap, or install rivnuts where you marked the masking tape. If you purchased a Matte Black shroud that includes extra fasteners, they are metric M6x1 threads. For side mounted "Top Hat" radiators, the side rectangular mounting points do NOT have coolant flowing through that area. You can drill through it, without fear. If you do not have flanges, or the rectangular braces, you most likely have a very thin alluminum structural brace runing vertically on each side. Depending on the radiator, you can drill a 3/16" hole, but use a drill bit collar so you do not drill too far. You can then use pop rivets to secure the included side brackets. (Best to have those side brackets mocked up to the shroud, after you mount the side brackets, remove the shroud)
4. Install shroud flap doors
The rubber flap door nibs need to be installed with the three holes at the top of the door opening, when the shroud is vertical. (Most shrouds can be mounted up, or down, depending on where you want the fans to be located) Insert the rubber nibs into the matching row of holes. Using pliers, pull on the rubber nib, which makes it thinner, and pull gently through the hole. Release and reset the pliers, continue until the flap door is flush with the shroud. To remove the flap door, use pliers to pull on the nib to make it thinner while at the same time pulling the flap door to remove it.
5. Mount the Shroud
Mount the shroud on the radiator. If you used the drill and tap method, we recommend using Blue Threadlocker. Be careful as not to overtighten.
6. Mount the Radiator with Shroud
Mount the radiator and shroud in your car.
7. Mount the fans
Best to mount the fans AFTER the radiator and shroud are in the car. Install each fastener loosely, before tightening all fan mount fasteners. All shrouds have M6x1 threaded holes, unless otherwise specified.
Frequently Asked Questions
Do I need to drain the coolant to install a fan shroud?
If you remove the radiator from your car, yes. Otherwise, No. A fan shroud mounts to the radiator frame and does not require opening the cooling system. No coolant drainage needed.
How do I know if a shroud is compatible with my vehicle?
Check the product listing for fitment details — we list compatible makes, models, and shroud dimensions. When in doubt, contact us with your radiator part number.
Can I run my vehicle without a fan shroud?
Technically yes, but it's not recommended. Without a shroud, the fan pulls uncontrolled air from around the radiator rather than through it, significantly reducing cooling efficiency — especially at low speeds or idle.
My shroud doesn't line up perfectly — what should I do?
Minor misalignment is common due to manufacturing tolerances. Check that the radiator itself is seated correctly first. If mounting holes are off by more than a few millimeters, contact us before forcing the fit.
Is the shroud compatible with both electric and mechanical fans?
All of Fast Monty's shrouds are designed for electric fans unless otherwise noted.
Need Help?
If you run into fitment issues or have questions about your specific vehicle, contact us — we're happy to help you get the right part installed right.
