Diono Radian 3RXT Installation – The Baby Swing

Last Updated on August 22, 2023

Welcome to our user-friendly guide for installing the Diono Radian 3RXT car seat! Buckle up as we take you on a step-by-step journey to ensure your child’s safety on the road. The Diono Radian 3RXT is a top choice for families, known for its safety features. But let’s admit it – car seat installation can be a puzzle. Don’t worry. We’ve got your back. 

We’ll break down each step in a way that’s easy to follow, with handy tips along the way. Whether you’re a newbie parent or just upgrading, let’s work together to master installing the Diono Radian 3RXT. Your child’s safety is our priority, so let’s get started on this installation adventure!

Diono Radian 3RXT Installation

Installing Diono Radian 3RXT Rear-Facing: Step by Step

When you’re ready to set up your Diono Radian 3RXT car seat, just follow these simple and clear instructions:

Step 1: Inspect the Diono Radian

Before commencing the installation process, inspecting your Diono Radian 3RXT car seat is essential. Ensure there are no visible signs of damage or missing parts that may compromise its functionality or safety.

Step 2: Install the LATCH System

Begin the installation by setting up the LATCH system. This process involves threading your SuperLATCH or vehicle’s seat belt through the rear-facing belt path on your Diono Radian 3RXT. Ensure the belt is flat and not twisted to secure a firm fitting.

Step 3: Attach the Top Tether

The next step is attaching the top tether. The need for this step can vary depending on your vehicle’s specific make and model, so it’s always advisable to refer to your vehicle’s owner’s manual for accurate instructions.

Step 4: Install the Seat Belt

If you opt to use your vehicle’s seat belt instead of the LATCH system, you’ll need to thread it through the rear-facing belt path, buckle it, and then lock the vehicle seat belt. This process helps in securing the car seat in place.

Step 5: Secure the Diono Car Seat

After setting up the LATCH system or seat belt, the next step is to secure the Diono car seat. Pull on the SuperLATCH strap or seat belt to tighten it. A properly installed car seat should not move more than an inch side-to-side or front-to-back when you give it a firm shake at the belt path.

Step 6: Adjust the Harness

Finally, adjust the harness to fit your child. When the car seat is installed rear-facing, the harness slots should be at or slightly below your child’s shoulders. This adjustment ensures maximum safety and comfort for your child during transit.

You Might also Like These Resources!

How to Put in the Diono Convertible Car Seat for Forward-Facing?

Diono Radian 3RXT Installation

Putting in the Diono Convertible Car Seat for Forward-Facing involves a few simple steps. It’s important to note that only forward-facing vehicle seats should be used with this child seat, and side-facing or rear-facing seats cannot be used.

Here are the steps you need to follow:

1. Place the Diono Car Seat: Begin by putting your Diono convertible car seat onto the vehicle seat. Slide it in so that the back of the car seat is right against the back of the vehicle seat.

2. Thread the SuperLATCH: Next, thread either the SuperLATCH or the vehicle’s seat belt through the forward-facing belt path on the car seat. Make sure the belt is flat and not twisted in any way.

3. Connect the SuperLATCH: If you’re using SuperLATCH, connect it to the lower anchors in your vehicle. If using the seat belt, securely buckle it up.

4. Secure the Diono Car Seat: Pull the SuperLATCH strap or tighten the seat belt to remove slack. Try giving the car seat a firm shake to check if it’s snug enough. It shouldn’t move over an inch sideways or front-to-back at the belt path.

5. Adjust the Headrest and Harness: Adjust the headrest and harness to match your child’s size. The harness slots should be either at your child’s shoulders or slightly above them.

Adjusting Straps on Your Diono Convertible Car Seat: A Simple Guide

Ensuring the straps on your Diono Convertible Car Seat are correctly adjusted is crucial for your child’s safety and comfort. Here’s a simple guide to help you out:

Step 1: Unhook the Harness First, unhook the harness from the metal splitter plate at the back of the car seat. This plate is where all the straps converge.

Step 2: Re-thread the Harness Next, pull the harness through the front of the car seat. Choose the appropriate set of harness slots for your child’s size. The harness slots should be at or just below your child’s shoulders for a rear-facing seat. They should be at or just above the shoulders for a forward-facing seat.

Step 3: Secure the Harness After re-threading, secure the harness by hooking it back onto the metal splitter plate. Ensure the straps are not twisted and lie flat against your child’s body.

Step 4: Adjust the Tightness Finally, adjust the tightness of the harness. It should be snug but comfortable. You shouldn’t be able to pinch any excess strap at the shoulder once it’s tightened.

Diono Radian 3RXT Car Seat: Keeping it Clean

Keeping your Diono Radian 3RXT Car Seat clean is essential for maintaining its functionality and lifespan. Here are some tips:

Regular Vacuuming: Regularly vacuum the car seat to remove crumbs and dust. Use a soft brush attachment to prevent damaging the fabric.

Spot Cleaning: For small stains, use mild soap and cold water to spot-clean the affected area. Avoid using harsh chemicals, as these can deteriorate the fabric over time.

Deep Cleaning: The Diono Radian 3RXT has a removable cover that can be machine washed on a gentle cycle. Remember to air dry the cover to prevent shrinkage.

Cleaning the Buckle and Harness: Clean the buckle and harness with a damp cloth. Avoid submerging them in water, as this could affect their functionality.

Remember, a clean car seat is aesthetically pleasing and healthier for your child.

Safety Measures

Keeping your child safe while traveling begins with proper car seat installation and usage. Here are some important safety measures:

Correct Installation: Ensure the Diono Radian 3RXT Car Seat is installed correctly. Whether using the LATCH system or the vehicle’s seat belt, the car seat should not move more than an inch side-to-side or front-to-back when given a firm shake at the belt path.

Right Position: Babies under two years old should be in a rear-facing car seat. They may transition to a forward-facing seat when they exceed the maximum weight or height limit for the rear-facing seat.

Harness Adjustment: Ensure the harness is properly adjusted and lies flat against your child’s body. The chest clip should be at the armpit level.

Avoid Bulky Clothing: Bulky clothing can create extra space between the harness and your child, reducing the car seat’s effectiveness. Instead, cover your child with a blanket over the buckled harness.

Always prioritize your child’s safety and regularly check the car seat for any signs of wear or damage.


How do I know when my child can transition to a forward-facing seat?

Children should remain in a rear-facing car seat as long as possible until they reach the car seat’s maximum height or weight limit. This can vary between models, so check your Diono car seat’s user manual for specific limits.

Is Diono car seats flame retardant?

According to the information, Diono car seats contain flame retardants. However, it’s important to note that all Diono car seat fabrics are tested to ensure they do not contain any legally restricted or harmful flame retardants. The brand claims to use materials that meet federal flammability standards without adding chemical flame retardants. However, some tests have shown that certain Diono models may contain TDCPP, or “tris,” a flame retardant that some consider toxic.

Can I use a seat mat or towel under my Diono car seat to protect my vehicle seat?

Diono recommends using only Diono-approved accessories with their car seats. This includes seat mats, like the Diono Ultra Mat, designed to protect your vehicle seat from spills, dirt, and dents. While you might be tempted to use a towel or other type of mat, these can interfere with the proper installation of the car seat and may provide a different level of protection than a Diono-approved mat.


Installing and using the Diono Radian 3RXT car seat is important for keeping your child safe while traveling. Just follow the steps we discussed, like picking the right spot, securing it properly, and ensuring it fits well. Cleaning the car seat is a good idea, too, to keep it nice and comfy.

Remember, facing the car seat backward is safer for smaller kids. And the Diono car seats can work for a long time as your child grows. So, by taking these steps and using the car seat right, you ensure every ride is safe and cozy for your little one.

You Might Also Like These Latest Content!

Jessica Booth is a freelance writer on parenting and product reviewer.
She has two kids of her own, so she knows a lot about the subject. Jessica has been writing professionally for over five years, and she's had articles published on sites like Bustle, Romper, Forbes, Parade, Business Insider, Good House Keeping, and more. Jessica is passionate about helping parents who are struggling. She believes that every parent deserves to have the tools they need to be successful. As a freelance writer, Jessica is able to share her knowledge and experience with others through her writing. Read more

Leave a Comment