Introduction: How to Install a Rear Spoiler on a 2010 Hyundai Genesis Coupe - Measurements Included!

Picture of How to Install a Rear Spoiler on a 2010 Hyundai Genesis Coupe - Measurements Included!

It's one thing to bolt or stick on accessories, but drilling into your trunk (or any other part of your car's bodywork for that matter) is not for the faint of heart. This guide is pretty much aimed at giving anybody the confidence to drill their trunk in order to install an OEM (or non-oem) spoiler to your Genesis Coupe. If you don't have a Genesis, than it's still probably a pretty decent starting point if their isn't a specific tutorial for your vehicle.

The stock drill locations will be used for the easiest install. While I used the OEM drill template to locate the drill holes which made the install extremely easy, measurements are included so anybody with some measuring tape and a piece of string can locate the holes with the same precision.

As always, if you choose to follow this guide it's under your own risk. My install came out perfect, but yours may vary depending on your access to tools or skill level.

Note - This guide is focused on the OEM Genesis Coupe Spoiler installed on a 2010 Hyundai Genesis Coupe 2.0T Base Model. This DIY can also be used for the "OEM Style" spoiler using the hole location method located at the end.

Dificulty:
OEM Spoiler - 2/5
OEM Style Spoiler - 3.5/5

Hassle:
OEM Spoiler - 1/5
OEM Style Spoiler - 4.5/5

Time:
OEM Spoiler - 2 hours
OEM Style Spoiler 4 hours

Disclaimers:
Working on any vehicle can be risky to both yourself and the vehicle. No warranties or guaranties, explicit or implicit, are made or implied regarding the compatibility, suitability or effect on any current warranties. All modifications should be made within the reader's capability and under their own exclusive responsibility.

A bit of motivation to keep making instructables always helps. I'm a participant in the Amazon Services LLC Associates Program as well as eBay Partner Network, affiliate advertising programs designed to provide a means for creators to earn fees by linking to their sites, at no extra cost whatsoever to you.

Step 1: Which Spoiler?

Picture of Which Spoiler?

If you haven't purchased your spoiler yet, let me give you my opinion on the matter. Like always, Ebay is the place to start. Basically, you have two options and independent of where you buy it, the level of quality will be basically indistinguishable (or at least impossible to distinguish in the listing) so don't worry too much about it. I give you the thumbs up to simply priceshop . So there are two spoilers, the "OEM" spoiler, and the "OEM style" spoiler. Let me just start out saying that for the difference in price, the "OEM" version directly from Hyundai is vastly superior in the small details, but once installed the difference is quite small and almost negligible. I know because I purchased both, but ended up selling the "OEM Style" after buying the "OEM".

The "OEM Style" will cost you as low as 130$, whereas the "OEM" model will run you about 230$ (as of 2015 when this guide was first written. Currently the OEM version seems much harder to source and more expensive). I'm talking about shipped to your door prices from Ebay. Truthfully, it's where you'll find the best prices. The difference in paint finish between either is virtually non existent. They both have a very nice finish, with no defects worth mentioning. I'd even say better than my stock paint.

The general shape of both is identical, as is the main mounting points. The OEM version, which is manufactured by Hyundai, does feel better built and heavier (in the high quality type of way) but truthfully, from more than a few feet away once installed it's impossible to distinguish them apart.

The brake light on both work the same, but the "OEM style" has to be soldered or connected manually to the stock brake light harness (a trivial task), whereas the "OEM" version is "Plug and play" with a connector already wired to it. The brake light on the "OEM" version is slightly larger than the "OEM Style" if I remember right, but you can only tell if they are side by side, if not you'd never know.

Besides the plug and play electrical plug of the "OEM" spoiler, the other thing that made me like it a lot more was that the OEM spoiler has a nice molded rubber gasket to seal the spoiler to the trunk, whereas the "OEM Style" only has a very cheap, oversized and more or less poorly cut piece of foam which will most likely be slightly visible after installation. This alone justified the difference in price to me.

The final aspect would be that the "OEM" version is much easier and quicker to install by one person given the fact that it has "Guide rods" where it screws into the trunk. This way a single person can align the spoiler with the trunk closed, drop the guide rods into the drilled holes, open the trunk with the guide rods keeping the spoiler in place and directly screw the bolts into the guide rods from the inside of the trunk with the trunk door in vertical position. Without those guide rods, you need two people to hold the spoiler exactly in place with the trunk door open while you screw in 4 bolts from the inside.

As far as drill locations, both use the same drill locations for attaching the spoiler, but the hole for the electrical connector of the third brake light is different, though easily found knowing the position of the other two holes.

By the way, the reason I bought the OEM spoiler after buying the OEM Style was that the OEM style includes no instructions whatsoever as to where to drill the holes, and I wasn't about to drill into my trunk in the wrong place just to save 100 bucks. But that is no longer an issue for you guys since in this DIY you will find the drill locations so either can be installed.

After initially making this DIY I was made aware that some OEM-Style spoilers have a mounting base which doesn't perfectly mate with the trunk bodywork, so nowadays I'm much more cautious about recommending it. I'd say only buy OEM-Style if you can't find the OEM spoiler at a price you'd be willing to pay.

Let me summarize that for you. If you want the absolute lowest price, then the "OEM Style" is fine. I'd say that the paint quality of both are virtually identical (although the mounting base may vary slightly). But if you have to install the spoiler on your own or with only one other person, want ease of install and a high quality finish, or basically just love your car, buy the "OEM" spoiler. If you want to save money, save it on your girlfriend, not your ride . In any case, buying the OEM spoiler directly from Hyundai with installation can easily be in the 700$ range, so installing it yourself for 250$ is a steal. For the extra 100$ it's definitely worth it.

Step 2: What You Will Need

Picture of What You Will Need

As far as tools, you will need the following (Parenthesis indicates desireable but not necessary) items. All links below are either to their product page on Amazon or Ebay for your convenience.

  • OEM Spoiler Drill Hole Template (or string and measuring tape)

Step 3: Find the Right Spot

Picture of Find the Right Spot

Find a nice, spacious, horizontal place and set aside around 5 hours just in case. It should take much less though. For installing the OEM Spoiler you need between 1 and 2 extra pairs of hands to install. For the OEM, you could do it alone but a friend definitely helps.

First let's start by cleaning off any dust or dirt on the trunk and surroundings that could scratch the finish of the paint if we lean against it. Then, I definitely recommend applying 2 or 3 quick layers of wax. We will be applying, moving and removing tape so it helps reduce the amount of residue left over afterwards.

Step 4: Remove Trunk Lining

Picture of Remove Trunk Lining

Remove the interior lining of the trunk. I have no pictures of this step since I already had it removed, but basically all that you need to do is pry off the black friction screws. A body panel pry tool (basically a plastic fork) helps, but it is not necessary. Be careful to keep all of the "screws" since they will be reinstalled afterwards. Be careful to not scratch the paint underneath the black lining.

Step 5: Install Template

Picture of Install Template

Start by applying the OEM Drill plate to the trunk door. First apply the small, thin, black strips lining it up with the bottom corner. It should be within 2mm of the trunk edge all around. Feel free to remove and reapply until you are happy with it's position. The strips are side dependant, so make sure you're applying the right strip to the right side.

After that apply the large transparent template lined up with both the trunk edge and the edge of the applied strip. Once you start, applying the strips should be more or less intuitive. After applying the template to both sides, apply a strip of painter's tape underneath the hole markings of the template to keep from scratching the finish with shavings while drilling, and to keep the drill bit from sliding around when starting the hole.

Be careful! If you are installing an OEM Style spoiler, the third hole on the left side is in a different position, but easily found measuring off your spoiler and having located the two mounting holes.

Note: Please do not ask in the comments where to buy the drilling template. It comes with the OEM spoiler, and is not available for sale separately.

Step 6: Start Drilling

Picture of Start Drilling

Remove the drill template, and use a center punch to mark all of the drill holes. Given how easy the drill bit could dance or slip, this should be considered non-negotiable.

There will be 3 holes on the left side and two holes on the right side (OEM Spoiler). Start by drilling a pilot hole of your choosing with any small-ish drill bit.

Step 7: Drill to Correct Size

Picture of Drill to Correct Size

After that, decide how you are going to drill the actual holes. In my case I used a step drill bit, but either a drill bit of the correct size or a hole saw would work. Remember to use high quality bits, and operate at moderately high speeds drilling with confidence. Do not apply excessive pressure, the body panels are only a few millimeters thick and will bend if you press too much.

Note: Large drill bits should not be used to make holes in sheet metal - it creates triangular holes.

Step 8: Deburr Holes

Picture of Deburr Holes

Now we have to deburr the holes. While a small file or even sandpaper can be used, proper deburring tools cost under 2$ on Ebay and will make your life alot easier. Remember to use constant, light pressure and to deburr both the "outside" and "inside" of the hole.

After that, feel free to remove the tape and clean off any shavings. Be extra careful and blow or brush off shavings, but do not use a cloth since you will scratch the paint! Compressed air is the ideal solution. A recommendation for that professional touch would be applying some quick dry scratch repair paint to the edges of the drill holes to avoid rust in the future.

Step 9: Attach Spoiler

Picture of Attach Spoiler

If you've gotten this far, the worst is over and you'll be testing out the lights in less than 30 minutes in most cases. That, or very pissed off at drilling in the wrong place.

Now we have to place the spoiler in place. The OEM Spoiler is a lot easier to install thanks to "guide rods" which are simply dropped into the drilled holes and screwed into from the inside. With the OEM Style spoiler you have to hold the spoiler in place somehow while screwing in the 4 screws from the inside.

The first step is to run the electrical cable for the third brake light through the middle hole on the left side (in the case of the OEM style spoiler, the hole is behind the two mounting posts). After that, simply drop the guide rods in and screw in the bolts from the inside.

I would personally recommend applying a thick layer of wax to the gasket under the spoiler for a better seal, but it is by no means necessary. Apply thread locker (either Blue/Medium or Red/Strong) to the bolts before screwing in. After all, you don't want your new spoiler turning into the hood ornament of the unlucky guy driving behind you.

Step 10: Route Third Brake Light Cable

Picture of Route Third Brake Light Cable

Once the spoiler is properly screwed in and secure, route the electrical cable through the trunk and attach with zip ties.

Unplug the stock connector from the stock OEM third brake light, and plug it into the spoiler harness. If you bought the OEM Style spoiler, you will need to solder the cables yourself. It is only two cables, but polarity matters so make sure the brake light works before permanently attaching the electrical connector.

Finally, make sure that the trunk door properly opens and closes without damaging the electrical cable for the spoiler.

Step 11: Test the Brake Light

Picture of Test the Brake Light

Note: The extra weight of the spoiler makes the trunk door bang a lot harder. If you install the spoiler, I definitely recommend getting the OEM Strut for the Genesis Coupe w/ Spoiler. The part number is 817712M010 and both struts tend to cost about 59$ shipped.

Test the brake light. If it works, great news, you're done! Now take a nice ride to try it out.

If you found this interesting, click the 'Follow' button up on the right to get notified of similar projects in the future, or check out my profile to see what other projects I've been up to.

Step 12: Extra - Measurements of Spoiler Drill Locations

Picture of Extra - Measurements of Spoiler Drill Locations

The following measurements are for whoever doesn't have the OEM template for the drill locations, or for someone who purchased an OEM Style spoiler which does not include anything other than "drill hole locator tabs" (which would be a very bad idea to use in a case like this where an OEM location exists, specially with a multilayered unibody trunk door). To see the image in high resolution, click here. You will need metric measuring tape and a piece of string. Also consider applying painters tape to the approximate location of the drill holes, or even taping a piece of paper so that the markings are made on something other than the trunk door. As long as you measure with precision, this method is just as precise as using the OEM drill template. I still recommend purchasing a spoiler that includes the OEM drill template, but if you didn't your still covered.

All measurements will be taken with respect to the upper left and right corners of the trunk door, where the sharpest angle is formed. What we will do is trace arches centered at those two points, whose intersections will precisely mark the drill hole locations. If you do it right, this is just as precise as the OEM template given that you could only be off by less than half an inch per some 3 or 4 feet. When I took the measurements, both sides agreed with each other within less than 3mm over more than a meter, which is pretty precise. You can be very confident that using this method you will nail the OEM drill spots and your spoiler will be properly placed and centered.

For example, to measure where the top left hole would be, you would take a section of string measuring exactly 30cm, with one point at the left top corner of the trunk door. With the other end of the string, you would hold a fine marker where the string ends (at the end of the 30cm), and trace an arch around the approximate position of the drill hole. Now you would have an arch centered at the left trunk door corner with a radius of 30cm. Then you would take the string and measure 111.5cm centered at the right top corner of the trunk door, and make another marking where the 111.5cm string intersects the 30cm arch traced before. The intersection of those two arches will precisely define the location of the drill hole. Now repeat for the remaining holes and you will have all of the drill locations.

Please remember that the hole to pass the electrical connector for the spoiler light does vary between the OEM Spoiler and the OEM Style spoiler.

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