How to Wash a Car Engine at the Carwash – A Detailed Step by Step Guide?

Written by

Bruce Sonnier


Marcus Dutton

how to wash a car engine at the carwash

A well-kept car inside and out is a must. So car owners must also keep in mind to clean their engine. Keeping it clean helps make spotting oil or fluid leakage problems easier; prevents buildup in engine parts, which may be flammable or corrosive; and if you plan on selling your car, helps keep your car presentable and adds to its value.

There are 13 steps on how to wash a car engine at the carwash. It may seem like a complicated task, but if you carefully follow the steps provided in this article, you’ll be able to do it successfully. This process would involve some precautionary steps, degreasing, scrubbing, rinsing, drying, and cleaning the electrical parts by hand.

What You Will Need to Follow this Tutorial


To achieve a clean car engine at car wash, you would need a couple of things. A washer or sprayer is readily available at the car wash, while you need to provide other things yourself.

Plastic Bags and Electrical Tape

In cleaning engine at car wash, you must be careful with the electrical components, as water might get in contact with them and damage them. So you must be prepared with plastic bags for covering those electrical components and electrical tape for securing the plastic covering.



Another precautionary measure would be to disconnect the battery cables from the battery. You would have to remove both the positive and negative terminals so that they would not get damaged when you wash the engine. To do so, you would need a wrench.

Vacuum, Cloth, Synthetic Bristle Hand Brush, Compressed Air, Leaf Blowers

These cleaning tools would be very helpful in engine cleaning. Debris on the surface can be easily removed with the use of a cloth. It also works well in loosening grime buildup. And for dealing with buildup in crevices, a brush would be convenient.

When working with hard-to-reach nooks and crannies when removing debris, you may use a vacuum, compressed air, or leaf blower.

When degreasing, an extra cloth would be handy in case the degreaser might splash on the car’s paint. Some degreasers, particularly solvent-based ones, can be damaging to the car’s paint. So they must be wiped off from the car if accidentally splashed.

Also, the cloth and brush would be ideal for hand cleaning the electrical components with only a little moisture.



An effective product that aids in getting rid of all the oil and grease accumulated in an engine is the degreaser or car wash engine cleaner.

There are different types of degreasers, namely solvent-based, water-based, citrus-based. They would come in the form of either spray, gel, or foam.

Solvent-based degreasers are much stronger than the other options and are highly effective in cleaning very dirty engines. Water-based and citrus-based degreasers are also effective but are relatively gentler.

Degreasers in spray bottles are very easy to apply by just spraying them on the surface of the engine. Gel and foam degreasers can stick to surfaces better and would not drip.

Dust Mask, Safety Glasses, and Rubber Gloves


The grime that dirties an engine is also hazardous. And these particles may splatter or fly onto your mouth and eyes. So as a safety measure, you would need a dust mask, safety glasses and rubber gloves.

Washer or Sprayer With a Low-Pressure Setting


Car washes usually have washers or sprayers with pressure settings adjustable to low and high. Check in the car wash if they have these provided first.

It is important to make sure you are using only low pressure. Water flowing at high pressure may leak into the covered electrical components and dislodge connections and parts.

Engine Bay Dressing (Optional)

The engine bay dressing is not always required but would work wonders for your engine if you want to give it a polished look.

It is especially helpful for those who are planning to sell their car in the future, as it keeps an engine looking new. Moreover, it gives an added protective layer from future buildup on an engine, which helps make cleaning easier.

How to Wash a Car Engine at the Carwash Step by Step instructions


Washing engine at car wash should be done carefully. Follow the steps provided below for successful execution.

Step 1: Set a Schedule for Cleaning

The perfect weather for cleaning an engine would be warm weather with low humidity and wind. With this type of weather’s ideal temperature and reinforcement of the blowing wind, drying the engine after the cleaning process would be quickened.

Step 2: Let Your Engine Cool up First

Before cleaning your engine, always let it cool down first. Flipping the hood open would help cool your engine. Let your engine cool down for several hours.

While you wait for your engine to cool down, you can do other things like wash and dry your car’s exterior if you’ll be doing the cleaning at a self-serve car wash bay or dilute your degreaser as per the directions on the label.

Step 3: Tighten up All the Caps and Dipstick

Chemical reactions and degradation can occur and damage your engine when water gets into its fluids. To prevent that from happening, you need to tightly seal the caps of power steering fluid, brake fluid, coolant, and other liquid reservoirs. You must press the dipstick down to ensure that it has been securely sealed.

Step 4: Disconnect the Battery Terminals and if Preferred, Also Take Out the Battery

Using a wrench, disconnect the two battery cables from the battery to keep them from getting damaged by the water. After disconnecting the cables, you may also remove the battery to clean more comfortably and thoroughly if you wish and if it is possible.

You can still clean your engine without taking the battery out if you don’t want to and if it’s not possible.

Step 5: Cover Electrical Parts and Filters

Electrical components such as ignition wires, spark plugs, coil packs, distributor caps, engine control units, alternators, and fuse box as well as filters need to be protected from water. These parts can be damaged when water gets in contact with them. You can protect them by covering them with plastic bags secured by electrical tape.

This step ensures you get to do a thorough cleaning of your engine without risking damage to any parts of it.

Step 6: Wear Protective Gear

You must wear a dust mask and safety glasses so that the hazardous grime would not accidentally get into your mouth and eyes. You must also wear rubber gloves for protecting your hands from the harsh cleaners and as stains.

Step 7: Remove the Debris From the Engine

Debris like dead bugs and leaves are often found in any engine. Grills, vent openings, and the battery are some debris magnets that you would have to take care of.

Most of the debris found on the surface of engines can be easily removed with the use of a hand cloth. But when dealing with nooks and crannies that are hard to reach, you may use a vacuum, compressor, or leaf blower.

Step 8: Degrease Your Engine

Prepare your degreaser according to the instructions on the label. Some degreasers don’t require diluting, but since they all vary in formulation, others would require diluting before use.

To aid in the removal of the dust and grime on the surface of your engine, loosen up the dust and grime by scrubbing them with a synthetic bristle brush and vacuuming them up.

And to help make the degreaser work more evenly and prevent spotting caused by the degreaser drying on the engine while cleaning, spray on some warm water with the use of a spray bottle on your engine. Spraying warm water also prevents cracking and warping on the parts that may have not totally cooled down yet.

When applying the degreaser, do it starting from the bottom going to the top. It helps to keep yourself clean while cleaning your engine.

Spray out the degreaser thoroughly all over your engine compartment. Apply more degreaser to parts that typically accumulate a lot of grime such as hoses, caps, fluid containers, and the firewall.

A brush or cloth can also help to break up the buildup in your engine. You should also have an extra cloth in case of accidental splashes of degreaser on your car’s paint. The degreaser must be left to soak on the engine for 10 minutes.

Step 9: Rinse Out Your Engine

When rinsing out your engine, use only low water pressure. Do the rinsing starting from the back going to the front. Don’t spray water directly on electrical components. And don’t spray too much water on parts that won’t easily dry.

Step 10: Dry up Your Engine

Same as when washing cars, you should not let your engine air dry, as it would cause water spots and undo most of the hard work you’ve done. Instead, wipe it down using hand cloths. You may also use a compressor to get rid of excess water in nooks and crannies.

Afterward, you may let your car run for about five minutes to help dry the inner components. And you may also keep the hood up for more or less an hour to help the engine completely dry.

Step 11: Clean Electrical Parts by Hand

Remove the covers from the electrical components and dispose of them properly. With the use of cloths, brushes, and only a little moisture, clean those electrical components by hand.

Step 12: Put the Battery Back

If you have taken out the battery from your engine, place it back once all the parts have completely dried out. Then reattach the battery cables.

Step 13: Apply Engine Bay Dressing

This step is optional. You can do this if you are not content with simply cleaning your engine but also want it to shine.

Applying engine bay dressing is as simple as spraying it on the surfaces of the engine bay and letting it sit for about 30 minutes to an hour. After letting it sit for some time, you would have to wipe it off with a cloth.


Was this guide a pleasure to read? Having a clean car can be very satisfying. But it would take some effort, and in the case of cleaning the engine bay, should be done with much caution. It is important to keep in mind the proper way to do it.

Any thoughts on this article are welcome in the comments section, including tips on how to wash a car engine at the carwash. And if you find this a great article worth sharing, you’re free to hit that share button.

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