A major accident can be a traumatic event, but there are a lot of small bumps that are easy to forget because your Acadia's bumpers stop the damage. Whether someone on their phone rolls into you while you're in line to load your crossover onto the ferry, you back into a low pole or that trailer hitch wasn't quite where you thought it was, or you hit something while doing a little off-roading in the Cascades, the bumpers can help keep your GMC out of the body shop. Of course, there's a lot more going on than just a piece of plastic cladding, and when the bumpers do get damaged, there's more at stake than you may realize.
Acadia Bumpers: A Practical Solution
GM pioneered the modern bumper with the Endura, introduced on the 1968 GTO. Instead of having a chrome bar attached to a set of shock absorbers, it used multilayer construction capped with a plastic exterior. This lets the bumper deform and pop back into shape after minor impacts.
Despite this innovation, trucks and SUVs have continued to use metal bumpers to provide a structure that can support the weight of a trailer hitch. However, GMC's designers know that Acadia owners are more likely to be driving their vehicles in the city than down on the farm, putting the rear at a higher risk of minor collisions. That's why the crossover's bumper is separate from the hitch, allowing the engineers to use plastic construction for greater durability while still letting the vehicle tow as much as 5,200 lbs. when properly equipped.
How a Bumper Protects You and Your Vehicle
The bumper encompasses all the body parts on the vehicle below the grille on the front end and below the lift gate on the rear end, but only the center section is built for absorbing bumps since this is the most likely area of contact.
The bumper cover is made out of a flexible plastic that covers the end of the vehicle. There's quite a bit of space between it and other bumper components, letting it flex under minor impacts. While the paint might get scratched, the cover itself will usually be undamaged.
There are two parts that absorb larger impacts: the absorber and the impact bar. The absorber is made of a very dense styrofoam that crushes to absorb most minor bumps. If the impact is harder, it will push through this barrier and into the impact bar, which is a piece of spring steel. On the front end, this bar mounts to the frame, while the rear bar is mounted on a large inner support that provides a rigid backbone. In a major collision, the bumper acts as the first crumple zone. As it collapses, the force is then transferred to the fenders and frame, spreading out the impact force through crumble zones and away from the cabin to reduce the chance of injury. To get the most out of your crossover's safety features, the entire bumper need to be structurally sound.
The Other Functions of a Bumper
The bumper covers are shaped to improve the aerodynamics of your GMC. To help the air move around the vehicle, lower covers attach to the main bumper cover, extending past the impact structure to push air away from axles and other mechanical components. To help the bumper cover maintain its shape, there are small side supports inside that aren't part of the crash structure.
The rear bumper is above the trailer hitch, placing it high on the vehicle, but the front bumper is the lowest point on the vehicle. To protect it from scrapes when transitioning between steep angles or bottoming out the suspension, this cover is protected by an extension that bolts onto the bottom. The plastic is designed to withstand abrasion, and it's easy to replace if it becomes worn or damaged.
The radiator, air conditioner condenser and transmission cooler are all mounted behind the bumper structure. To supply enough air to these components, the Acadia has a lower grille that supplements the main grille. There are also small grilles on the corners of the bumper for styling.
To meet Federal regulations for visibility, the rear bumper has reflectors built into the sides. Have fog lights? Those are build into the front bumper cover. Need to mount a license plate on the front of your Acadia? There's a bracket that attaches to the bumper cover.
How Difficult is it to Replace Bumper Components?
GMC doesn't use retaining clips on these components, so everything is attached with either a bolt or a screw that can be removed and installed using common hand tools. Of course, these parts will only install correctly if the surrounding body components have been repaired so everything lines up with the attachment points on the new parts.
To make ordering parts easier, we have factory diagrams for different component sections so you can see everything that should be installed, including specialized nuts that slip in between body part sections.
Worried about rust from sea water exposure? Fortunately, while many of the fasteners are metal, they screw into plastic bolts and clips so corrosion is never much of an issue.
Do Bumper Components Need to Be Painted?
Chromed and solid plastic parts come ready to be installed, but parts that should be body colored come unfinished from the factory. These parts need to be sanded, primed and painted before installation.
Why are there Core Charges on Some Components?
We sell genuine GM parts, which means we must adhere to their sales requirements. For some components, the automaker wants us to return used and broken parts. There are two reasons for this:
GM can recycle these parts, melting down plastics and metals to make new components. This helps the environment and helps reduce parts costs.
It keeps parts from being refurbished by aftermarket companies. These parts often don't meet OEM requirements, and that means they may not offer the level of safety your vehicle was built with. For example, an impact bar that is repaired by bending and welding it back to shape won't flex the same way a new bar will. This repaired bar will either resist flexing, transferring more impact energy to the vehicle, or it will break, leaving the frame unprotected. GM has even found instances where parts have been removed from dumpsters of auto body shops to be resold, so they've been working with shops and individual purchasers to keep these damaged parts out of the market.
Where Can I Get the Right Parts to Fix My Acadia's Bumper?
At GMPartWorld.com, we only sell OEM GM parts, built by GM to provide the same fit, appearance and performance as the parts that came with your SUV from the factory. Our site has factory diagrams along with search tools that let you find parts by your model, VIN, keywords and even part numbers. Have questions about parts or core exchanges? We have a professional parts staff who can answer them.