Don't Do These Car Repairs Yourself

We always recommend doing the repairs on your car yourself, like carrying out regular vehicle servicing and even provide you with guides to make your job easier. But some vehicle repairs are too intricate, complicated, or borderline dangerous if not done properly and are beyond the scope of most average DIYers. Attempting to carry out complicated and technical tasks without prior knowledge or experience can end up costing you more in repairs than the actual mechanic’s labor, let alone the safety hazard that it will pose. 

Plus, some service jobs require specialized tools and equipment that are only available at auto repair shops and dealerships. Especially in modern vehicles with their endless array of computerized gizmos and electronic bits that are only fixable with the right electrical tools exclusive to professional garages. Here we showcase a few jobs that are better left to the pros. 

In this article:

Car Repairs You Should Never Do Yourself

Timing Belt

The timing belt or chain controls the engine’s timing and synchronizes the cam and crankshaft. It is an essential engine component that requires proper replacement or the results are catastrophic. This is simply because if the crank and cam are not aligned properly, the valve’s movement timing is altered which can result in colliding valves and pistons which of course can scrap your engine completely or require massive repairs that can cost a lot. Therefore, a timing belt replacement job is best left to the pros. 

Head Gasket

head gasket failure is one of the most challenging tasks even for a skilled mechanic as it requires hours of disassembly making it very time-consuming. Depending on how hard it is to access the engine in your car, the mechanic may even have to remove the engine completely before attempting to swap the gasket, making the job all the more difficult. So if you find your engine’s head gasket is leaking, then have it replaced professionally and save more in the long run. 

Spring/Shock Absorber

The springs in your car support the entire weight of the vehicle, and so they are under immense compression force at any given moment. This means the springs are loaded with energy and are essentially a projectile waiting to set off when the support structure is released which is usually the control arm or the shock absorber. Springs, shock absorbersstruts, and control arms are major components that are very dangerous to repair without the right tools so we urge you to have your mechanic do it safely and accurately for you. 

HVAC System Components

The heater core is tucked away behind the dashboard and has lines running to the firewall. Due to its location, the heater core is very hard to access and makes the repair job extremely complicated. You have to remove all the dashboard and HVAC system components, and electricals, and then remove the dashboard in order to even access the heater core. The complexity of the job is what makes this task hard for most people. Even if you are able to pry apart all the components, putting them back in the right order is a mammoth task on its own. This is why heater core replacements are best tackled by skilled mechanics. 

Similarly, other HVAC system components like the blower motorevaporator, etc. are hidden behind the dashboard making them hard to access in case of replacements requiring complete dashboard disassembly. 

AC System Components

The AC lines are pressurized with freon or refrigerant which are harmful chemicals that can cause serious damage upon exposure. Whenever working on any AC system components in the car it is mandatory to flush the freon before replacing any component such as the car's AC compressor. The removal and refilling process of the freon requires special tools and technical know-how and so any AC-related jobs must be handled by professionals. Also, the freon needs to be disposed of properly and such disposal methods are only available at professional garages. 

Brake Lines

The brake lines in modern cars carry the hydraulic brake fluid which is pressurized within the brake line. These brake lines have a tendency to rust at which point they need to be replaced. Most modern cars have solid brake lines that are precisely cut to length and are shaped strategically to fit tight clearances. These lines have many bends and angles that are very hard to replicate especially without the proper tools. The brake lines also need to be fit with the right set of connectors and bungs that secure them to the cylinders. Therefore, the replacement job of brake lines is very time-consuming, and complicated, and must be done right for utmost safety which is why it must be done professionally. 

Bodywork Repairs And Paint Jobs

It is quite common to come across botched bodywork repairs as they can be quite the eyesore that diminishes the look of the entire car. Replacing bolt-on components like the vehicle fenderhood, doors, etc. is an easy job that can be done yourself but parts like the quarter panel and roof require extensive cutting, drilling, and welding to get right. This requires a lot of technique and skill along with experience to get the job done precisely which is why we recommend consulting a bodywork specialist for any bodywork repairs. Small dents and scratches also need special attention as a lousy job can be easily distinguished from a professionally done job. 

Even if the bodywork is done right, the paint job is one such thing that is almost impossible to get right with rudimentary tools. Expertly crafted paint schemes are used to get the accurate matching color of your car which cannot be duplicated with a spray paint can. That is why paint jobs must always be carried out by trained professionals no matter the extent of the job required. 

Windshield Repair

The windshield is not just a glass for viewability but also serves as a structural part of the vehicle holding up the roof. Messing up a windshield repair job may even cost you a complete replacement. Removing the windshield requires specialized equipment and more than a single set of hands along with a lot of caution. Putting back in the new glass is also hard since the glass needs to sit precisely in location and must be glued in with the right type and amount of adhesive for a leakproof seal. Leaving such precision jobs to professionals will give you the peace of mind of a job well done and also prove to be more economical in the long run.


The automotive transmission is one of the most complicated pieces of machinery in a vehicle. Be it manual or automatic, the transmission has several moving parts all interlocked in a complicated fashion. Even a small misplacement of a cog can result in complete transmission failure which is why it is best to leave the transmission alone. If you face transmission-related issues then have your mechanic take a look at it before you go about snooping. 

Fuel Injection Components

Unlike the olden days when fixing the carburetor was a joy, modern cars with their fuel injection have completely different components at work that cannot be simply fixed with a spanner. Fuel injection requires fuel to be delivered at extremely high pressures and has many intricate components like fuel rail and injectors. These components do not follow the same protocol for replacement as a spark plug and pose a serious safety hazard if the replacement is not done right. Any fuel delivery components like the fuel tankfuel pump, injectors, rail, and fuel lines must be professionally removed and installed.


The engine is the powerhouse of the vehicle. Every engine component is assembled with extreme care to fit tight tolerances. Even a small variation in a single bearing or ring placement or a bolt not specced to torque can have catastrophic results. If your engine requires restoring, rebuilding, reboring or any such process then have it done by a specialist for the best results and prolonged engine life. 

Airbags & Seat Belts

Safety components are parts that must never be fiddled with, let alone carried out a replacement. An airbag replacement is very time-consuming because you not only have to replace the airbag unit but also repair or replace the entire dashboard or seats that the airbags have deployed through. Trying to replace detonated or damaged airbags can not only prove laborious but can sacrifice the most important aspect which is safety. Most airbags send out error codes when deployed or damaged which show up on the driver’s dashboard. Even after the airbag or seat belt is replaced the error codes can remain and require troubleshooting with electronic code readers and testing tools. A professionally done job will ensure the system works properly and restores the safety of the vehicle. 

ECU Tuning

The ECU or Electronic Control Unit is the most important electrical component on most modern cars. The ECU controls, regulates, and supervises all the sensors and actuators in the vehicle and is responsible for maintaining optimal engine performance. Trying to decipher ECU readings and alter various timings is a disastrous task for unknowing amateurs and can have wrecking results. ECU tuning is an extremely complicated task that only highly specialized and certified mechanics perform. Reading the ECU error codes is one thing but attempting ECU tuning or repair is completely different, Most elementary code readers are not suited for ECU tuning and must never be utilized without expertise. 

Adding Induction Devices Like Turbo And Superchargers

Sure, we all want more power from our engines, but at what cost? Performance over safety is not a wise choice and here's why. Introducing a turbo or supercharger into an engine induces a lot of extra stress and forces on all the engine components. There are a lot of considerations like engine reinforcements, mounting locations, plumbing, electricals, etc. that need to be done before the turbo and supercharger are fitted to the engine. After adding the devices, the engine has to be tuned and recalibrated to match the inputs of the forced induction device. The job of adding induction devices is much easier said than done and requires careful planning and integration for a successful job which is why it is recommended to consult professionals for such tasks. It is common now to find many off-the-shelf turbo and supercharger kits for many popular engines that even provide instruction guides for installation. But such kits can only help you so much. You will need considerable knowledge, tools and a lot of time for the process and the results may not be rewarding. A professional on the other hand will do the job right in a fraction of the time without sacrificing the safety of the vehicle. 

So next time you come across the aforementioned repairs or upgrades, don’t shy away from consulting a professional. You may have to dig deeper for the initial labour costs but remember you can always save costs on the car parts and get huge discounts while purchasing them yourself at Partsavatar. 


Articles and Guides that are written with the help of mechanics to ensure you have all the knowledge you need to make the correct purchase here at PartsAvatar.

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John Framigllia
Technical Writer
Our technical writer is known for simplifying automotive parts and services. Intuitive with various vehicles and manufacturers, he knows how to simplify complicated problems.