2021-up Kia K5

Overview of the Kia K5

Rare is the sedan that can accurately be described as "eye-meltingly gorgeous," but the Kia K5 definitely qualifies. This astonishingly sleek four-door, which replaced the Optima in Kia's ever expanding (and improving) lineup, offers plenty of interior space, impressive luxury touches, and even the outstanding warranty that Kias have long been known for. It would be a thoroughly nifty package even if the wrapping weren't so nice. But oh, how nice it is.

As with many new cars, radio replacement isn't always recommended for the K5. But if you want a car that sounds as good as it looks, upgrading the audio system with new speakers and subs will do the job. Read on to learn what you can do and how to do it.

The K5's factory radios have plenty of cool, useful features. That's a good thing, because they're kind of challenging to replace. (Crutchfield Research Photo)

The factory stereo system

The K5's stereos are, like the rest of the interior, much nicer than you might expect in a car at this price point. The base receiver is an 8" LCD receiver with Apple CarPlay® and Android Auto™. The factory upgrade is a 10-1/4" LCD. The top-of-the-line system combines the big LCD with a 12-speaker Bose® audio system. The Bose system’s amplifier is located in the trunk, behind the passenger's side access panel.

Removing the factory radio isn't easy, but if you really have to do it, we can tell you how it's done (Crutchfield Research Photo)

Removing the factory radio

The factory receivers have all the features you’d expect in a modern stereo, which is a good thing, since replacement can be challenging.

As we write this, the aftermarket has yet to produce a dash kit or a wiring harness that will work for the Bose system. You can replace the base model, though. The dash disassembly process is neither quick nor easy, but it is a do-able DIY project if you work patiently and stay organized.

When you replace the factory radio, you'll lose some factory features. If you have questions, give us a call.

All the disassembly instructions you'll need can be found in the Crutchfield ResearchNotes™ included free with your Crutchfield car audio purchase.

Tools needed: Panel tool, Phillips screwdriver, small flat blade screwdriver

Read our Car Stereo Buying Guide for shopping tips and advice.

Shop for car stereos that fit your Kia K5

Speaker replacement is the quickest, easiest, and best way to upgrade your car's audio quality. (Crutchfield Research Photo)

Removing the factory speakers

Whether you have the 6-speaker base system or the 12-speaker Bose system, upgrading the speakers is the best way to pump up the volume in your K5.

The Bose system includes this center dash speaker. (Crutchfield Research Photo)

Removing the center dash speaker (Bose only)

The K5's Bose system includes a 3-1/2" center dash speaker that's reasonably easy to remove and replace.

Starting at the rear edge, use a panel tool to pry up the center dash grille. Once you've released nine retaining clips, remove the grille and set it aside. Next, remove the two Phillips screws securing the speaker to the dash, then disconnect the harness and remove the speaker.

A wiring harness is not available for this speaker, so you'll need to splice, solder, or use Posi-Products speaker connectors to connect the new speaker to the car's wiring.

Tools needed: Panel tool, stubby or right-angle Phillips screwdriver

All K5 systems include corner dash speakers. They're reasonably easy to reach and replace. (Crutchfield Research Photo)

Removing the corner dash tweeters

All K5's have corner dash speakers that are wired in parallel with the corresponding front door woofers. They're also pretty easy to deal with, though you'll need to splice, solder, or use Posi-Products speaker connectors to connect the new speaker to the car's wiring here, too. Also, you'll need to fabricate a mounting bracket or use our universal backstraps to replace these 1.606" tweeters. Hot glue or silicone will work, too.

To remove them, start at the rear edge and use your panel tool to pry up the tweeter grille to release three clips. Disconnect the harness and remove the tweeter/grille assembly, then pry the tweeter out of the grille.

Tools needed: Panel tool, small flat blade screwdriver

You'll need to remove the door panels to replace the front door speakers. (Crutchfield Research Photo)

Removing the front door woofers

The front door woofers (base or Bose) are 6-3/4" models that can be replaced by a variety of same-size or 6-1/2" aftermarket speakers. Removal and replacement is reasonably easy here, too, but there are some things to keep in mind when you're choosing your new speakers.

You'll need mounting brackets to install any new speakers in this location, and if you're going with 6-3/4" models, you'll need to remove the inner tabs on the aftermarket speaker bracket. We'll include the mounting brackets with your Crutchfield speaker purchase.

There's no wiring harness available for the Bose speakers, so you'll have to splice or tap the vehicle's speaker wires to your new speaker wires. Posi-Products speaker connectors are another (easier) option here. Also, note that replacing these low-impedance Bose speakers with standard 4-ohm aftermarket speakers will result in lower volume levels.

Detailed stereo and speaker removal instructions

With step-by-step disassembly instructions and plenty of up-close, detailed photos, our exclusive Crutchfield ResearchNotes™ takes the guesswork out of removing the factory audio gear. It's free with your Crutchfield order, or you can purchase one separately for just $9.99.

Getting the old speakers out of there starts with removing one Phillips screw located under door armrest. Next, start at the lower corners and use your panel tool to pry out the eleven clips holding the door panel in place. Disconnect the door release cable by pressing the release tab, then disconnect the harnesses and remove the door panel. Finally, you'll remove the four Phillips screws securing the speaker to the door, then disconnect the harness and remove the speaker.

Tools needed: Panel tool, Phillips screwdriver

The Bose system's midrange speakers are mounted in the door panels. (Crutchfield Research Photo)

Removing the front door midranges (Bose only)

The Bose system’s midrange front door speakers are "3T" models that measure 2-3/4" in diameter. This size isn’t a common one just yet, but an increasing number of automakers are starting to use them, so the aftermarket is making more of them. The selection isn't vast at the moment, but it’s growing.

These speakers are attached to the K5's door panel, so when you remove the panel to get to the woofers, you're most of the way towards removing and replacing these speakers, too. All you need to do is remove the two Phillips screws securing the speaker to the door panel, then disconnect the harness and remove the speaker.

Tools needed: Panel tool, Phillips screwdriver

You'll need brackets to replace the door speakers, and we'll include them with your purchase. (Crutchfield Research Photo)

Removing the rear door speakers

In the rear doors, you’ll find another pair of 6-3/4” factory speakers. As with the front door woofers, you’ll need mounting brackets to install any new speakers in this location, and if you’re going with 6-3/4” models, you’ll need to remove the inner tabs on the aftermarket speaker bracket.

Starting at the top corner, use your panel tool to pry off the sail panel and release two clips, then remove the sail panel. Moving down the door, remove one Phillips screw located under door armrest.

Next, start at the lower corners and pry out the door panel to release twelve retaining clips. Disconnect the door release cable by pressing the release tab, then disconnect the harness and remove door panel. And finally, remove the four Phillips screws securing the speaker to the door steel, disconnect the wiring harness, and remove the speaker.

As with the front doors, a wiring harness is not available for cars equipped with the Bose system. You'll need to splice, solder, or use Posi-Products speaker connectors to connect these speakers to the car’s wiring.

Tools Required: Panel tool, Phillips screwdriver

Getting to the Bose system's rear deck speakers isn't easy, but once you're there, you can replace the speakers and the sub. (Crutchfield Research Photo)

Removing the rear deck corner speakers and subwoofer (Bose only)

K5s equipped with the Bose system include three rear deck speakers – a pair of 2-1/4" speakers in the corners and a 9" subwoofer in the center. The good news is that you'll use the same basic steps to get to the speakers. The not-that-good (but not bad) news is that there are a fair number of steps involved.

None of the steps are vastly complicated, but this is a bit more work-intensive than replacing the other speakers. It's nothing a reasonably skilled DIY-er can't handle, but you'll need to set aside some time, stay organized, and stay patient. Enlisting a helper might be a good idea, too. Complete, detailed removal instructions can be found in the Crutchfield ResearchNotes included free with your radio or speaker purchase.

It's important to note that there are air bag harnesses back here. Make sure the negative battery cable is disconnected before you disconnect them.

You'll need to fabricate a mounting bracket or use our universal backstraps for the corner speakers, and you'll need another set of Posi-Products speaker connectors, too.

You can replace the stock Bose subwoofer with a variety of 8" aftermarket subs, but since they're not an exact size match for the speaker openings, you'll need to fabricate a mounting bracket or spacer. You'll also need to splice or tap the car's speaker wires to the new sub's speaker terminals.

And, as we mentioned earlier, replacing the low-impedance factory sub with a 4-ohm aftermarket model will result in lower volume levels. Shop accordingly —– look for low-impedence subwoofers. If you have questions, give us a call.

Tools needed: Panel tool, 10mm deep socket, 12mm socket, ratchet, and extension

Read our Car Speakers Buying Guide for more information.

Shop for speakers that fit your Kia K5

There's plenty of room for boom in the K5's spacious trunk. (Crutchfield Research Photo)

Bass in your K5

If you want to add even more bass performance to your ride, the K5 has a good-sized trunk that'll give you some room for boom. The available space measures 39" W x 20" H x 43"/32" D, so a subwoofer box can work here. If you want to boost the bass without losing too much cargo space, check out our selection of powered subwoofers.

Learn more about building a bass system in our Car Subwoofer Buying Guide.

Adding Dynamat to your K5's doors will help seal in sound.

Other options for your Kia K5

Here are a few other smart ways to improve the sound in your K5.

Add an amp (or two)

A new 4-channel amplifier will help you get the most out of your new speakers. You'll get cleaner power (and a lot more of it), which will result in much, much better sound. A mono amp can provide the juice you need for your new subwoofer, too. Learn more about adding amps to your system in our Car Amplifier Buying Guide.

Sound processor

Since you'll be keeping the factory radio, install a sound processor to send a clear, clean signal to your new amplifier. Sound processors remove any limitations on the signal imposed by the factory radio, and the better the signal, the better the sound. Read our article explaining factory sound processors to learn more.

Dynamat

The Dynamat 10435 Xtreme Door Kit is the perfect way to seal in sound. This heavy-duty insulating material is easy to install, and it really makes a difference. One kit will take care of the front doors. If you install a big sub, you might want to line the trunk lid as well.

Security systems and remote start

Installing a security system in your Kia won't be easy (security systems rarely are), but it's definitely a good idea. Our Crutchfield Advisors can help figure out what you need to get the job done, but we usually recommend taking your car to a professional installer.

Adding remote start capability to your K5 lets you warm it up in the winter or cool it down in the summer. Installation is usually easier with these systems, but we still ask that you call to order so that we can make sure you get the right harness for your ride.

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