How to Clean an Engine Bay The Right Way | Autance

Read through our tricks and tips on the process

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How to Clean an Engine Bay The Right Way | Autance © How to Clean an Engine Bay The Right Way | Autance

Your engine is the beating heart of your car, and it is important that you do everything that you can to keep it in top condition. Any issues are likely to be expensive and time-consuming to put right. And if it is possible to prevent them with some extra care and attention, this is something which is certainly worth doing. Detailing your car’s engine is a task which removes accumulated dirt, dust, and grime, but it is one which many car owners simply don’t know about or one which they avoid as they think that it is going to be overly complicated. We are here to show you how simple it can be and to help with this guide which breaks the process down into more manageable parts.

Why is it Important?

Let’s start by talking about why detailing your car engine is so important. Engine bays accumulate dirt very quickly, and if this is not thoroughly cleaned off, it can lead to the degradation of essential components like the pulleys and bearings. It also gives you the opportunity to check for any other signs of engine damage such as leaks and corrosion. You can determine the cause of any oil or grease leaks and get these repaired before a small problem escalates into a much larger one. When the hood gets flipped up, you can care for this as well.

If you like to undertake minor engine work on your car, the job becomes just a little bit easier if the engine is clean as your hands and clothes are not going to end up covered in gunk. A clean engine will also improve your vehicle’s resale value as it is a sign of a car which has been well-maintained. Serious car buyers are likely to be put off by engines which look like they have never been detailed properly. And when you take your car into a mechanic and they see a detailed engine, they know that they are dealing with someone who knows what they are doing and takes good care of their engine.

Remember that engine detailing is a delicate job which requires a gentle touch. Keep in mind that modern cars are much easier to detail that their older counterparts. Many of them are covered in a plastic shrouding and the electric connectors are protected with durable plastic housings and assembled with moisture-protecting grease. Thanks to electronic ignitions, there are no old-fashioned distributers and carburetors. The alternators are the last remaining area which have the appearance of exposed wires. At the same time, modern engines are well protected from dirt, water, and other potentially harmful substance es.

Is it Difficult?

Detailing a car engine is not an especially difficult task. Most contemporary engines only get covered in dirt and oil rather than getting caked in thick, heavy grease. Just think of it like the other regular maintenance tasks you undertake in and around your car. The job involves a few basic steps, which we will go into more detail about later in the blog post. First, you need to spray cleaner or degreaser over the entire engine and bay. You then need to rinse it off with a low-flow water nozzle, before blowing the area dry to clear off the excess water. Next, you can polish up all the essential components, before using an engine dresser on the area. It is a process which should only take between 20 and 45 minutes, depending on how dirty the engine bay is. Once you become more skilled, you should be able to reduce the time spent cleaning.

How Often Do I Need to Clean My Car’s Engine Bay?

The frequency with which you need to clean your car’s engine bay depends on several different factors including where you live, the weather conditions etc. If you live in an area with low rainfall and low dust levels, simply cleaning it once or twice a year should be enough. However, if you live in an area with harsher weather conditions and lost of dirt and dust in the air, you may want to complete this task as often as every two or three months. Otherwise, a good general rule of thumb is to simply check on its condition and clean it if it appears to be getting dirty.

Step-by-Step Guide

1. Gather Your Materials

Before you get started, make sure that you have all the appropriate materials, substances, and equipment that you require to complete the task. You are going to need engine degreaser, a water hose, plastic bags, a bucket, drip pan, wash brush, car wash mitt, car wash soap, absorbent pads, microfiber towels, a plastic and metal cleaner. Also, it helps to have a vacuum with a small nozzle and some compressed air for drying those hard to reach areas. If you try to use a high-pressure hose or steam cleaner, this could cause damage to the electrical parts and connections. However, you can complete the job in its most basic form with a degreaser, protector, and cloths.

Related Post: Best Engine Degreaser

Choosing a degreaser is often the task which people take the longest over, but you don’t necessarily have to worry so much. The majority of cleaners with some type of degreaser will do the job just fine. If it has been a long time or you have never detailed your car engine before, you may need a heavy-duty degreaser, which is a little tougher on the built-up grease and dirt. Bear in mind that if it can cut through the oil or grease, it will also remove any wax on the car paint. You should avoid using general cleaning products such as WD-40 or Windex on the engine bay.

Related Post: Best Oil Drain Pans

2. Make Sure the Engine is in the Right Condition

Many people are afraid of detailing their car engine as they think that they are going to cause damage. But modern engines are highly resilient pieces of equipment, so it should be fine if you take the necessary precautions. Bear in mind that if you are working on a classic car or one which has been made before the mid-1990s, you need to proceed with a higher degree of caution.

First, you should make sure that the engine is cool before getting to work. This means leaving it to stand for a while after you have driven the car. Ideally, you should leave it overnight, but an hour or so with the hood up is usually enough. Don’t try to speed up the process by throwing a bucket of cold water over a hot engine it as this will increase the risk of causing damage.

Before you begin the process, you should give the engine an initial hose down as this will clear a lot of dirt and help the degreaser to spread further. Ensure that all essential features are covered including the alternator, exposed filters, and air intake. You don’t want water or degreaser to gather in these areas. You can cover the air filter with a bag or some tin foil, but don’t forget that you need to remove these before starting the engine again.

If any custom work has been undertaken which has led to exposed electrical connections or gauges, you should also cover these up. Bear in mind that you should only use the amount of water or cleaner you need to complete the job effectively, so don’t overdo it. In general, water will not harm the engine bay as it is specially designed to resist moisture.

Remember that there are hundreds of moving parts in your car’s engine and it would be an extremely time-consuming task to clean them all thoroughly. If the job has not been done in a long time, it is inevitable that the first time will be the hardest. However, if you detail the engine regularly, it is bound to get easier over time. If this is your first time doing this job, you are bound to feel a little bit nervous. Take your time and do it little by little.

3. Degrease the Engine Bay

First, you should degrease the perimeter of the engine bay with a specially designed engine degreaser. This is better than standard soap as it cuts through the oil. Choose a high-quality product if you want to do the job well. As we have just mentioned, a cool engine is better than a warm one. Otherwise, the cleaner will dry too quickly. You can use the degreaser safely on the painted surfaces but bear in mind that it will cut through wax. Make sure to concentrate on the fluid containers and hoses as these areas get particularly dirty. Spray the firewall at the back of the engine bay as far as you can. It is better to start from the lower areas and work your way up. This will stop the degreaser from dripping on you as you clean the underside parts. You should allow it to remain in place for a few minutes to ensure that it does its job properly. Keep an eye on the degreaser during this time as you don’t want it to dry on the surface.

Afterwards, you can rinse it off with a slow stream of water from a host or pressure washer. If you only have a high-pressure nozzle, you should be careful not to get it too close to the covered electrical connectors.

To get rid of the more stubborn remains of the degreaser, scrub it down with a soft-bristled brush that isn’t going to leave any scratches behind.  This is necessary to get into the cracks and crevices around the engine. An old toothbrush is a useful tool to get into areas which you can’t reach with other brushes. You may need a car wash solution on heavy soil.

If you have not detailed the engine bay in an especially long time, it may be necessary to repeat the degrease, rinse, and scrub steps multiple times to ensure that you do a thorough job.

4. Continue Cleaning by Hand

Once you have rinsed the engine off as much as possible, you should allow it to air dry for several minutes. You can then use a towel to wipe off the accessible parts. The rest of the detailing of your car’s engine involves cleaning it by hand.

Mix a solution of soapy water in a spray bottle to help you with your task. If you have a wash mitt which has been specially designed for engine detailing, this makes the job a whole lot easier. You can also get long-handled brushes which allow you to reach into areas which would otherwise be very difficult to access. The bristles need to be soft and chemically resistant to ensure that the brush is effective without causing damage. After you have gone around the perimeter of the engine, you can then focus on the central area where the degreaser may not have reached. You may have to put in a little more effort to properly scrub the fluid containers and caps.

Once you are satisfied that you have done a good job, you can then rinse everything off again. Stick to the type of low-pressure water which we discussed earlier. You can then remove any plastic bags or cling wrap which has been covering up some of the engine components as you know that there are not going to be any more splashes of water.

5. Polish Plastic and Metal Parts

Before you proceed onto any polishing or waxing work, you need to make sure that you thoroughly dry the engine. Use a specialized blower if you have one. Alternatively, a can of compressed air will blow water out of the cracks and crevices. For the plastic parts, you should use a high-quality protectant or plastic cleaner. You can apply it with the terry cloths and remove it with the microfiber cloth, which will help to remove any small scratches on it. You can wax the painted sections if you like, but a good-quality sealant is another viable option. As for the metal parts, you can use a special metal polish.

Related Post: Best Metal Polishes

6. Dry the Engine Out Again

There are a couple of useful tools which can dry the engine such as a leaf blower or pressurized can of air to remove the excess water from the bay. You can then start your engine until it reaches its regular operation temperature. You could also turn on your car’s AC unit to run the compressor at the same time. All of the engine components should dry out in around five minutes or so.

7. Apply Engine Dressing

If you want to do an especially thorough job, you could take the opportunity to apply some spray-on engine dressing once the engine has cooled. While this isn’t a strictly necessary step, it will leave your engine looking at its very best. Ultimately, it adds some shine and makes the bay look as good as new. It is the kind of uniformed appearance which you cannot get from simple degreasing and pressure washing. It also adds a barrier for dirt and dust to attach itself, making it easier to wash off the next time you come to detailing the engine.


While detailing your car engine is not an overly complicated task, it is one which is worth doing on a regular basis. For many people, detailing an engine sounds like an extremely complex task. Others are are afraid to go anywhere near their car engine. But modern vehicles are specially designed to resist damage, and they are well covered up in plastic. Remember that it is unlikely that you are going to cause a serious issue by detailing your car engine, but it is still a job which is worth taking your time over to do it properly.

Once you get into the habit of cleaning your car engine, it becomes easier as not so much dirt, grime, and debris will accumulate. Use the above steps and materials required as general guidelines to follow. Over time, you will gradually start to improve your skills and you can finish in as little as 20 minutes. Modern day engines are well protected, as well as being easy and safe to care for.

A couple of the main advantages of undertaking this task include allowing the engine to cool more efficiently and preventing damage to the individual components. It also gives you an excuse to check on the car engine to make sure that everything appears to be in good working order. If you decide to sell your vehicle in the future, a clean engine bay will show potential buyers that the car has been very well cared for.

Ultimately, this is a task which doesn’t have to take a great deal of time, but it is one which is worth it for everyone who loves their vehicle and wants to keep it in the best condition possible.


  1. How to Clean an Engine – YourMechanic Advice
  2. How Car Engines Work – HowStuffWorks
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