Top 10 Most Common Car Repairs

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Here at Car Bibles we talk a lot about car maintenance. Not just because we enjoy playing with all the cool tools, but also because it can be a real money saver. That is because the average car repair bill can easily run into the hundreds of dollars, so if you can take care of just a few of the most common cars repair issues you can save a lot of cash.

In this article we’ll go through 10 of the most common repairs that any at home mechanic should learn to tackle. We’ll look at the symptoms and signs of each issue, as well as take a look at the easiest repairs that can be performed at home.

By the way, we didn’t tackle tire changes in this article, as we’ve covered it elsewhere.

Catalytic Converter Replacement


  • Fuel Efficiency Drops
  • Loss of Engine Power
  • Vehicle May Fail to Start
  • Service Engine Light on Dash Display


First off all, you may not need to rush out for a full replacement. Before dropping the big bucks on a replacement, give a catalytic cleaner a try. They only cost a few bucks and are very simple to use, so you haven’t really got anything to lose.

If you try a cleaner and still no improvement, it may well be time to bite the bullet and replace your catalytic converter. There are two methods with regards replacing the converter, which will depend on if your vehicle’s converter is a bolt on style or integrated into the exhaust manifold.

Replacement is pretty easy though, especially with the Bolt On style. You just have to get the car up onto a car jack, get underneath that and, with a wrench set, undo the bolts and remove the old converter. Put the new one in place and attach it securely with the bolts.

Loose Fuel Cap


  • Loss of Fuel Efficiency
  • Smell of Gas (or Diesel) in the Vehicle
  • Check Engine Light


If the dreaded check engine light comes on, of all the things that can set it off, this could be the best of them. Why is that you ask? Well, it’s because it is such an easy fix! Next time you fill up, just take a second to see if the fuel cap is sealing properly. If it very easy to undo, if there is not the tell tale hiss of pressured air and if you can regularly smell gas in your car chances are it is not sealing properly. Luckily the repair is easy. Buy a new fuel cap, throw the old one in the trash.

Oxygen Sensor Replacement


  • Falling Fuel Efficiency
  • Engine Sounds Rough when Idling
  • Jerky Acceleration
  • Rotten Egg Smell


The oxygen sensor works by monitoring the oxygen that enters and leaves the catalytic converter, with one sensor being placed at either end of the converter chamber. It can get gummed up with carbon and other deposits, so again it can be an idea to flush the fuel system with a catalytic converter cleaner. In this instance look for one that states it is formulated to clean the oxygen sensor as not all of them are.

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If that doesn’t do the trick, you’ll need to pick up a set of new sensors that are suitable for your car. Check the installation materials for your car (either in the vehicle manual or online) but in nine cases out of ten, you simply jack the car up, grab your handy wrench kit and remove and replace the sensors.

Mass Air Flow Sensor Replacement


  • Difficulty Starting Engine
  • Engine Stalls Frequently Especially Just After it Starts
  • Acceleration is Jerky
  • The Engine Makes Hiccup like Sounds


The mass airflow sensor is another of those engine problems that may not be as big a deal as you first fear. Before you look to replace it, you should try to clean it first. The air mass sensor lives in the air filter unit, so when you are cleaning or replacing the air filter just take an extra five minutes to clean the mass sensor too.

No you only need a screwdriver. If you don’t have a screwdriver, well how have you managed to get this far in life without a screwdriver? Check out our guide to the best screwdriver sets here for crying out loud. Use the screwdriver to remove the sensor, and pop it into a plastic bag full off rubbing alcohol. Give it a good shake then very carefully remove and let it air dry for 20 minutes or so.

If that doesn’t do it, just buy a new one (of the right model for your vehicle) and replace the defective sensor.

Spark Plug Replacement


  • Trouble Starting the Car
  • Engine Does Not Idle Smoothly
  • Decreased Fuel Efficiency
  • Poor Acceleration


Ah, spark plugs. They are one of the classic car repairs because they are both a highly important component, but also easy to change. Open up the hood and remove any coverings or “boots” on the spark plugs. Put a spark plug socket onto your wrench and remove the old plugs. Replace with a new set of shiny spark plugs and away you go.

Just make sure you don’t over tighten the plugs when you replace them. That is probably the most common error that people make, and it can prevent the spark plugs from firing properly. It’s also a good idea to replace all of the plugs at the same time.

EGR Valve Replacement


  • Reduction in Power, Efficiency and Acceleration
  • Check Engine Light
  • A Rough Sounding Idle


The EGR, or Exhaust Gas Recirculation Valve, works to re-circulate exhaust gases back into the engine to reduce cylinder temperatures. It also plays a part in reducing emissions. It can get very dirty so it does need a good clean every now and then.

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The first thing to do is to locate and remove the EGR. It will usually be found toward the top of the engine block, but check your vehicle manual if you can’t find it. Disconnect the battery and loosen the bolts that hold the EGR Valve in place. Soak the valve in a bucket full of Carb Cleaner, unless your EGR Valve has any electrical connections.

If it does you’ll need to clean it by hand with something small like a toothbrush, getting into all the nooks and little openings. Again, if cleaning doesn’t do the job it may be time to order a replacement part instead.

EVAP Purge Control Valve / Solenoid


  • Check Engine Light
  • Vehicle Struggles to Start Immediately After Refueling


The EVAP Purge Valve (or Solenoid) is a key part of the vehicle fuel system. The EVAP system helps the vehicle to control the amount of fuel vapor in the tank by absorbing excess vapor in a charcoal lined chamber. The Purge Control Valve gradually opens as the vehicle is driven, venting that vapor into the engine to be burned up with the rest of the fuel.

When the valve sticks or is full out broken, it will not vent gas vapors properly. The good news with this device is that since it is almost always located at the top of the engine block, is it is nice and easy to access. It is a little fiddly to replace though, so this is one of those repairs it a good idea to watch a video on to see exactly what is going on.

Ignition Coil Replacement


  • Shaking Engine
  • Engine Making a Spluttering Sound
  • Engine Misfires
  • Lack of Acceleration Power
  • Check Engine Light
  • Cars with Only One Coil Won’t Start


The ignition coil is, as the name suggests, part of the vehicle ignition system. It essentially converts the relatively low and steady 12 volt power supply from the battery into a high voltage supply to power the spark plugs.

Whilst they can fail on their own, they can also be damaged by water entering the engine block, or by old, worn out spark plugs. Luckily, we write a whole guide on how to check your ignition coil, which you can find here.

If it has broken, there is no repair for the coil – it simply has to be removed and replaced with a new model. Luckily they are easy to replace. Simply disconnect the battery and locate the coils. They will be mounted to the top of the engine and screwed or bolted in place.

Undo the screws or bolts and disconnect the coils. The procedure can differ slightly with different vehicle types so refer to your vehicle’s manual for further instructions. Remove the old coil, replace with a new one. It’s also a good idea to change all your spark plugs at the same time as you install a new coil.

Oh if you drive a V8 the ignition coils will be mounted to the top and the rear of the engine block. That makes it a far more involved operation, and you’ll need to research how to get at the coils on your specific vehicle model.

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Intake Manifold Gasket Replacement


  • Overheating Engine
  • Leaking Coolant
  • Loss of Fuel Economy
  • Engine Misfires


The intake manifold itself is a cover made of aluminum, plastic or steel that sits right on top of the engine itself. The gaskets are made of rubber and plastic and they hold the intake manifold in place. The manifold works to ensure that the gas and air mixture the engine needs to operate is directed into the cylinders. It also transports coolant to the cylinder heads.

That makes it easy to tell when the gaskets fail, as the engine will overheat and it will also leak coolant. The gaskets are simply rubber and plastic tubes that connect the intake manifold to the engine so it’s easy to see if they are cracked or damaged, and if they you simply remove the top of the manifold then disconnect and replace the old gaskets. Put the manifold back in place, tighten all the nuts and bolts and you’re all set.

Thermostat Replacement


  • Engine Takes a Long Time to Heat
  • Or It Gets Too Hot, Too Quickly and Over Heats


The Thermostat monitors engine temperature and uses the built in cooling system to modulate it.  When the engine gets hot, the thermostat allows the coolant to flow. When the engine is cold, it keeps the coolant still and inside the block.

To change the thermostat, you must first allow the engine to cool completely, and then raise the vehicle up on jack stands. Locate the coolant drainage port on your vehicle model and drain the coolant from the system (an oil pan can be useful for this). The Thermostat itself is usually mounted beneath a protective housing on the cylinder head or close to the water (coolant) pump. Remove this housing and then remove the thermostat. Replace it with a new model and also change the gasket and seal that helps hold it in place. Refill the coolant system and you are done.


That covers ten of the most basic repairs that if you can master, you can really save some money in mechanics fees. All of the tasks that we looked at above can be done with a pretty basic tool set, and none of them are very complicated. The only thing to bear in mind is that the various components that we talked about can all look a little different depending on the make, model and even the year of manufacture of your own vehicle.

What we have done therefore is to give a very broad overview of the steps you need to go through to complete each repair. It is however a good idea to double check with a manual dedicated to your vehicle before you try anything out for the first time.

Originally posted 2024-01-03 11:16:49.

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