Online Fitting Tutorial

JDM Spec C roof vent install on a “newage” Subaru Impreza.


All of the parts required to fit this are available online at


First things first,

Fitting this part involves cutting holes in the roof of your nice shiny Subaru.

If you are not happy cutting the roof of your car, or are not confident using power tools, please feel free to Contact Me for a fitting quotation.



This guide is exactly that, a guide!

I cannot take any responsibility for any damage you make to your car or yourself whilst attempting to fit this part. All fitting, cutting and use of tools is undertaken at your own risk.


Taking your time, this can be done in about 4.5 hours. However, allow yourself plenty of time and do not rush.


Tools required.

  • Small terminal screwdriver
  • Small Phillips screwdriver
  • Medium Phillips screwdriver
  • Medium +drive screwdriver
  • Ratchet with, 8mm, 14mm sockets
  • Tape measure
  • Trim removal tool
  • Round needle file
  • Small smooth flat file
  • Piece of card (Cereal box will be fine)
  • Scissors
  • Safety glasses
  • Hand held drill
  • Selection of drill bits (2mm to 10mm will do)
  • Spot weld removing drill bit
  • Scribe
  • Centre punch
  • Paint pen
  • Ballpoint pen
  • Stanleyknife
  • 2 large plastic bags
  • Masking tape (2” wide preferably)
  • Small handheld disc cutter (Dremel® etc)
  • Metal cutting discs for the disc cutter


Start by using a small terminal screwdriver to gently pop the covers off of the seatbelt tops, this will expose a 14mm headed bolt. Remove the bolts and just allow the seatbelts to dangle out of the way.


Now pop off the tops of the B-pillar trims by pulling them gently at the top. These then lift upwards and out of the black lower side trims.



Fitting the vent requires the removal of the interior headlining. Everything that is attached to the headlining will therefore have to be removed beforehand.

Start by gently pulling down the rubber door seals from the tops of the doors. Repeat for all four doors. These are the ones that cover the edges of the headlining. They may be tight so be careful not to damage them.


Use a small terminal screwdriver to pop the clear lens out of the front map reading light.


This will reveal two small Phillips screws. Remove these screws and the light will drop down. Carefully unplug it from the multi-plug on the back. Note: (This will not be re fitted, as the new vent will be taking its place).

Pop the lens from the centre courtesy light in the same way. Again, remove the 2 screws and unplug.


Now remove the end covers from the grab handles with a small terminal screwdriver. This will expose a medium Phillips screw at either end. Remove these screws and remove the handles. Repeat for all handles.


Next are the sun visors. No covers to remove here, just the visible screws at either end.

Now the visors are removed. Use a trim tool to carefully pop out the fir tree clip mounted behind the centre visor. (This will be very tight so be careful not to break it or damage any trim).


Pop off the A-pillar trims by gently pulling them at the top. Be sure to pull them directly away from the vehicle pillar. They are held on by fir tree clips, so pulling them squarely reduces the chance of any breakages.

Carefully lift them out of the groove in the dash. Once removed, they will have the alarm sensor wires still connected. Leave these wires attached and just lay the trims on the dash out of the way.


Now do the same with the tops of the C-pillar trims. Do not fully remove these just pop the tops out to allow the headlining to be slid forward.


Finally there are the headlining clips above the rear bench. These are 2-stage clips. Carefully using a trim tool, pry out the inner part of the clip. These can be fully removed if desired. Then carefully pull out the black centre part.



Now the headlining should be fully unattactched from the roof skin. Double check everything to ensure nothing else is holding it in place.

Lie on the rear bench and slide the headlining forward out of the C-pillars and free of the roof skin.

Then once free, slide the headlining back and rest it on the rear parcel shelf. The front of the headlining should be supported by the tops of the front seats.


You will be greeted with the stock map light bracket. This is attached with three spot welds and three spots of RTV sealant. These spot welds are clearly visible and require drilling out using a special spot weld removing drill.

Centre punch the three spot welds to be drilled prior to drilling. Do not go mad with the drill, this is close to the actual roof skin so be careful.

Once the welds have been drilled, pull the bracket down gently and it will come away from the roof skin. You’ll be left with this.


Now for the first of your new parts, the inner vent frame.


Bolt this in place with the supplied fixing screws, only hand tight for now.

These will screw directly into the inserts already installed in the screen frame. These are located either side of the map bracket you have just removed.


Although in theory the vent can only fit in one place. It does have slotted fixings to allow approx 5mm of movement either left or right. Here’s where you have to measure, measure, measure.

Go have a cup of tea and then measure again. Once happy the vent is central and square tighten the two screws securely.


Now you are happy with the bracket placement. Carefully centre punch the four holes for the hinge studs.  Be certain to get these centred correctly, you have very little margin for error here.


This is where the fun starts. Mask the exterior roof skin with masking tape. This should ensure you do not scratch it when working outside the car. I used a large bag to cover the rear of the roof, just for convenience.



Time to drill the four centre punched holes for the vent hinges. Start off using a small pilot drill, 2mm will be ideal.

It’s a good idea to lay a big dust sheet inside of the car before drilling as this catches as much debris as possible.

Take your time, there’s no going back now!


By using a small 2mm pilot drill you have time make one final measure on the exterior of the roof before drilling the holes to full size (5.5mm)


Once you are happy with your hole positioning, you may drill them to full size.

It helps to go oversize by approx 0.5mm. This will allow the hinge studs to locate smoothly. The underside of the hinges has a rubber seal, so water ingress will not be not a problem.

Gently clean the edges of the holes with a small round needle file. Ensure there are no burrs on the holes before trial fitting your vent.


Trial fit the vent, and ensure the studs locate fully.


Tighten the vent down using the four M5 nuts supplied. Don’t worry that the roof is still masked; we will remove the vent again in a minute.



With the studs nipped tight. The inner vent frame should now be located securely.

Now for the inner vent trim.


Using the two black trim screws supplied, trial fit the inner vent trim. Nip the screws tight so the trim is secure.


The inner vent trim will provide the template of where the roof is to be cut for the main vent hole. To mark the roof, hold the trim against the roof skin and using a sharp scribe, carefully scribe the outline of the vent hole onto the roof skin.


Paint mark the edges of vent frame before removal. This just helps to re align it exactly later on. Now remove the vent and the frame. This needs to be out of the way to cut the hole.


Using your centre punch, pop centres on the scribed line. Keep these approx 25cm apart. I have paint marked these with a pen so they can easily be seen.


Using a small pilot drill (approx 1.5mm), drill holes around your scribed outline. These will be used to locate your template on the outside.


The exterior should now look like this clearly showing the position of the hole to be cut from outside the vehicle.


Using the inner vent trim, make a template on a piece of thin card by tracing the outline with a ballpoint pen.

It is important to note the orientation of the vent shape, as it is different from front to back.

Draw an arrow pointing to the front to avoid any confusion and cut this out with some scissors.


Now overlay your card template onto the roof and align it with the pilot holes previously drilled. You can now trace around the card template onto the masking tape using a ballpoint pen.


Tape a large plastic bag to the inside of the roof surrounding the hole to be cut. This will catch any sparks and debris that will drop inside of the car.


Okay, now for the best bit!

Using a Dremel® or similar with a small cutting disc, cut the hole in the roof.

Its also a good idea to put a large dust sheet over the windscreen at this point. The sparks although small can still mark the laminate on the screen.

Take your time, and dont forget your safety glasses!!!


Using a small grind stone or small file, clean the edges of any burrs left behind.


While the roof is still masked, paint the fresh cut edge with some “touch in” paint. The rubber seal does have sealant already in it that means this is not strictly necessary. However, we had some genuine WR blue paint so did it properly.

Time for a quick tea break, you’ll be gasping after cutting that hole! A quick break also allows your paint to dry.

Okay back to it, now you can remove the masking tape from the roof. Do this carefully. Look at that lovely clean hole… yikes!



Now remove the bag from inside the car and hopefully it has saved your interior from quite a bit of mess. You can now install the vent seal.

The seal has a join in it, I personally choose to place the join centred at the back of the vent hole, however you can put it at the front if you wish. Be sure to fit the seal with the large lip on the exterior and not the interior. Also check that the join is centred properly. The vent seal will really bite on to the roof hard so make sure you are happy with the position before pushing it on fully.


You can now re fit the inner vent frame. Use the paint marks you added previously to align it and torque the bolts fully.


Re fit the vent hatch with the supplied nuts and torque fully.


You may fasten the latch to the inner vent frame using the screws provided. However, this only to check the vents opening/closing operation. The latch must be unfastened in order to re fit the vehicle headlining.


Re fit the head lining in the reverse order to that of how it was removed. Slide it back into the rear C-pillar trims and attach the rear trim clips. Ensure the head lining is square at all times and be careful not to force it in any direction.


Carefully working from the back to front, re fit all the interior trim items, lamps, handles etc. Do not fit anything forward of the B-pillars yet as the headlining still requires cutting.

Ensure the headlining is square and loosely attach the front centre sun visor. This is only fitted to hold the headlining in place in order for it to be trimmed.


With the lining held in place. Align the inner vent trim with the holes on the vent frame. These will be visible through the existing hole in the lining, previously used for the map light.

With the trim in place, use a ballpoint pen to carefully trace onto the lining.


Carefully mark lines between the original hole and the oval you have just drawn. Remember, you can always cut more if needed but once cut, cannot be replaced. So cut a bit at a time.


Using a sharp blade, gently cut the lining away.

Caution: The lining cuts extremely easily with a sharp blade so be careful not to slip and cut away too much.


Keep trimming the lining until you are happy the inner vent trim fits snugly.

Once you are happy with the fit of the trim, re fit the rest of the interior trims. Sun visors, A-pillar trims and door seal rubbers etc.


With the lining now cut out and the last of the interior parts fitted. Fasten the inner vent trim, and vent latch mount using the two screws provided. The trim is held in place by the latch mount.

Ensure the trim is placed correctly and carefully drill the lining for the clips. Then finish with the new trim clips, ensure the clips engage into the mounting holes of the inner vent frame before pushing the centres of the clips home. They will bite tight holding the headlining and trim securely in place.

Ensure good operation of the vent and take the time to give the car a thorough vacuuming out.


Congratulations. You have a beautifully fitted Spec C vent.


Thank you for taking the time to read this guide, best of luck,


Frayz (“,) 


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