Plastic Cover Under Car Fell Off [Explained]

The plastic cover under car fell off! If you wonder what plastic pieces are and how they work, you come to the right place. The plastic covers under the car that come off are the engine splash shield or the fender liners. 

plastic cover under car fell off

Throughout this guideline, we will discuss why these pieces drop down and what happens if you ignore them or don’t install them. Turns out, we will let you know the amount of money you should spend to replace those parts. So, keep reading till the end. 

Plastic Cover Under Car Fell Off [Explained]

The plastic cover under the car that drops down is basically either the engine splash shield or the fender liner. Now, let’s go deeper into this chapter and discover why they fell off. 

Note: You can also read how to fix a metal piece dragging under car

1. Engine Splash Shield

It’s the protective plastic cover for the engine. You can find it around the engine area under the car. The purpose of this plastic cover is to protect the engine against corrosion from road salt.

engine splash shield

Also, it provides superior protection against gravel. In short, this piece of plastic element is a must if you drive in rougher areas. 

Generally, this plastic shield comes off or knocks off by road debris. And the debris buildup forms corrosion around the nuts and gets broken over time. 

If it falls off, we highly recommend you get a new one by spending $300 or more. It will prevent road debris from entering your car engine and reduce noise, which will also increase a little bit of mileage. 

2. Fender Liner

Fender liner is another plastic element that can also fall off or come loose due to corrosion. The plastic fender liner is generally mounted between the wheel and the fender. It shields the car body, wiring, and other electricals inside the wheel well.  

fender liner 

If this plastic fender liner comes loose or drops down, water or road debris can easily make its way into the wheel well and the back of the head assembly. Consequently, it will corrode the wiring installed inside the wheel well. 

You must tighten up the loose fender liner or replace it with a new one if it gets broken. Otherwise, you should deal with electric problems like no-start or headlight doesn’t come on issue. 

How To Fix Plastic Cover Under Car

Plastic cover under the car means either the engine splash shield or the fender liners. If they drop down, you should install them as they protect the engine area or the car body and wheel well wiring from the gravel or debris. 

Here, we will walk you through the steps to install both plastic covers. 

Install Or Tighten Up The Engine Splash Shield

First off, turn the engine off and wait for several minutes to let the engine cool down. Secondly, jack up your car, put an old rag down on the ground, and go under your vehicle with a flashlight.  

Then, look for the clips or screws that hold the engine splash shield. If the screws pull through the plastic cover, you should remove those screws and add some washers. 

Now, what you need to do is- align the plastic cover and screw up the cover. Keep in mind, that don’t hesitate to get a new plastic cover for the engine area if it gets broken. 

Repair Or Install Fender Liner

Repairing or reinstalling the loosened fender liner is not a challenging task. You can do it yourself if you have the right tools in your hand. To attach the fender liner to your car, you should have the following pieces of equipment at your fingertips: 

  • A rivet gun 
  • Some pieces of rivet 
  • A matching drill bit

Then, follow the steps mentioned in the following tutorial to install the fender liner successfully: 

How Much Does It Cost To Fix Plastic Under Car

The plastic under the car generally indicates the engine splash shield and the fender liners. Let’s see how much money you should spend on a replacement. 

Engine Splash Shield Replacement Cost

The part (engine splash shield) alone will cost you between $15 to $300. The price of most aftermarket plastic engine splash shields is between $15-$45. And the OEM part may eat up to $100-$125. However, the price may vary depending on the car brand, model, and year. 

If you want to install it professionally, you should spend between $45 to $65 on labor costs. In total, get ready to spend $60-$350 to replace the engine splash shield with a professional mechanic. 

On the other hand, if you install the engine splash shield by yourself, you just need to spend some bucks on the part alone. 

Fender Liner Replacement Cost

The replacement cost for the fender liner largely depends on the part’s availability and compatibility with your car’s year, make, and model.

Generally, it will cost you less than a dollar for a single unit or up to $730 for a set of units. If you install a fender liner, you should spend around $20 to $440. 


You must install the plastic covers under the car if they drop down. If you don’t install the engine splash shield, gravel, snow, or road debris can get into the engine and increase the noise. Similarly, the electric wiring inside the fender well will get damaged if you don’t install the fender liner. 

Luckily, we broke down everything from the replacement cost to the replacement procedure. So, get a new replacement part and install those plastic pieces following our guidelines or get it done by a professional. 

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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