Is the engine bay of your car so dirty that you can’t look at it without disgust? Well, you can always hire a professional service to clean the engine bay, but that would cost you a lot. With a little knowledge, you can do this on your own safely, and this guide will cover exactly that.
What Is the Best Way to Clean an Engine Bay? A 6-Step Guide
So let’s get on with the most obvious question, and that is how to clean your car’s dirty engine bay like a pro. First, make sure the engine is cool because cold water or chemical contact with a hot engine block can result in severe issues.
What You’ll Need:
- Gloves
- Safety glasses
- Microfiber towels
- Brushes (long-handled, toothbrush, painter’s, metal wire brush)
- Vacuum, leaf blower, or air compressor
- Pressure washer
- Soapy water (dish soap + warm water)
- Cleaning wipes
- Garbage bag or plastic cover
- Pipe cleaners
- Trim restorer (water-based)
- Spray wax
- Paint marker (optional)
Step 1. Preparing the Engine Bay
Before anything else, gather all your cleaning supplies and place them next to the car. This way, the whole process becomes quicker and more manageable because the products are right there for use.
It’s a good idea to wear gloves to protect your hands from chemicals and oils, and safety glasses in case any dirt or water splashes toward your face.
Since water is going into the engine bay, disconnect the battery’s positive and negative terminals to isolate the power source, so nothing’s active to short during cleaning. If the battery is right there in the engine bay and easy to reach, remove it completely. That opens up more space and gives better access to tight spots.
Now, even though the battery is disconnected, there are still a few parts you shouldn’t soak. Some water contact is fine, but not full-on spraying. For example, the fuse box, the alternator, and the distributor with spark plug wires or coil pack can take a splash, but it’s better to avoid soaking them.
You can either cover the coil pack on top of the car engine with a water-resistant material or press down the distributor caps and the spark plug wires to make sure they sit tight, which helps prevent water from slipping in.
Some newer engine bays come covered in plastic. These covers usually sit over parts that shouldn’t be exposed to water to make sure water doesn’t run under those panels.
Tip: Everything under the hood is designed to handle some water, which is why you can drive through rain or puddles without damage. The only difference here is that water is coming from above, not below. So, don’t use high-pressure jet setting to protect the essential parts of the engine.
Also, double-check the dipstick for engine oil. Push it in all the way so no water enters the engine.
Do the same for the brake fluid cap, power steering cap (if it’s not electrical), and the automatic transmission dipstick if your car has one. All of these must be a snug fit before moving forward.
Step 2. Dry Cleaning the Engine Bay
The next bit is dry cleaning, which means you need to brush the dust and loose dirt away before you introduce the water to the engine bay. That stops it from turning into thick grime and slipping into the cracks. You need brushes. You can use a toothbrush, a long-handled brush, a painter’s brush, or a metal wire brush for rougher parts in the engine bay.
To do this, use the brush and vacuum together to pull the dirt out from the top layer, first, and then brush around the tight areas in the bay. Next, use the vacuum again to remove the loosened dust from brushing.
For aluminum intakes with stains or dullness, scrub them with a metal wire brush. If the part is large, a rotary tool gets the job done faster.
However, do not rub it against plastic or rubber. That aluminum will look way better once the rest of the engine bay is clean.
Step 3. Wet Cleaning the Hood and Bay Surroundings
Next up is wet cleaning the engine bay, and it’s the part most people worry about, but once you know how to do it right, the job becomes simple.
Begin with the hood by placing a garbage bag over the engine, which shields the areas underneath, especially around electrical parts, from getting sprayed directly. Then, use the low-pressure jet setting on the washer to spray the water on the painted surfaces on the hood.
If the hood liner looks dirty as well, rinse that too, but if it sags or looks weak, leave it dry. Next, wipe these areas using a microfiber towel to remove grease and dirt. For heavy grime, you can spray carpet cleaner, let it soak for a bit, and then spray the water for quick removal.
Once wiped down, rinse the hood again to wash off any remaining dirt, and if stains are still there, those can be handled in the detailing step later.
Before removing the garbage bag from the engine, spray around the edges and clean the outside of the engine bay. Pick one side and rinse that area with water to remove surface dirt.
Now, use cleaning wipes to go over all the surfaces you can reach to absorb dirt and oil. After that, rinse again to wash away the loosened grime.
Spray your degreaser next. You can use a basic mix of dish soap and warm water. Coat the area and scrub it with a brush. If there are tight spots, use a pipe cleaner to reach them.
Once you finish scrubbing, rinse that area again. Repeat the process for the other sides: rinse, wipe, spray, brush, and rinse again. Each side takes around five minutes.
After all the sides of the engine bay are clean, carefully remove the garbage bag from the engine.
Step 4. Wet Cleaning the Engine without the Spray Hose
Now comes the trickier part, and that is cleaning the actual engine. First, take out the intake manifold if it’s in the way. That gives you better access and lets you clean that part separately.
Start by wiping off any thick grease with cleaning wipes. That layer should be removed because thick grease traps heat and acts like insulation.
Once that’s done, spray the engine using your soapy water mix in a fine mist. That mist is enough to cover everything without soaking anything.
Then use your brushes to reach every part you can access. For tight gaps, pipe cleaners fit well into spots where brushes can’t.
You can take a microfiber towel and wrap it around the pipe cleaner to reach deep crevices. If you don’t have pipe cleaners, a toothbrush works well on wiring or rough spots.
After you’ve brushed everything, wipe down each surface around the engine bay using microfiber towels.
Since you’re not rinsing with water here, the towel absorbs both the grease and the soap. Keep using clean towels until you’ve gone over the entire engine.
Now, some spaces, like the back or below the coils of the engine, are going to be really difficult to get into. Again, wrap a microfiber towel around a pipe cleaner and press it inside. That trick gets you into spaces you’d usually miss.
Step 5. Drying the Engine Bay
So now, you’re left with a wet engine bay. It’s best to use a clean microfiber towel and go over all surfaces to remove the moisture.
One thing that happens here is that your towel starts picking up leftover dirt that wasn’t removed earlier. In this case, use a little soapy water and wipe that spot down again.
At some point during drying, you may come across puddled water in tight spots. Those spots should be fully dried since any standing water can cause problems when reconnecting the battery. You can press the towel into those areas to absorb the water, or if you have a vacuum, use it to pull the moisture out.
The full engine bay should be wiped thoroughly to remove as much water as possible until everything is dry.
Step 6. Final Detailing and Protective Finishes
The last step is detailing the engine bay. First, pop off the clips and remove the hood liner. Then, spray your favorite spray wax across all the painted surfaces of the hood.
Now, use a microfiber towel to buff the wax into the paint. That brings out the color and gives the surface some protection.
Next, move to the engine bay and do the same for the painted parts. Spray, then buff.
After this, it’s time to detail the rubber and plastic parts. For this purpose, use a water-based trim restorer that dries non-greasy to darken these parts for a clean black finish, which protects them too. Just pour it on the black surface, and then use a clean brush to apply it on one side, and work around the bay.
Tip: Avoid using WD-40, motor oil, or anything greasy. Those products attract dirt and damage rubber. Also, avoid brushing the trim restorer onto the belts attached to the engine.
Let it sit and soak for about 10 minutes. Next, buff over every surface the brush touched with a microfiber towel. That removes the extra layer so it doesn’t collect dust and leaves a balanced finish.
You can stop here, but for extra detail, grab a paint marker and look around for rusted bolts or faded labels. You can clean rusty bolts with a wire brush, then dab some paint over them. That little touch brings the look together.
For faded lettering, like on a washer cap, just trace the raised letters with your paint marker. Details like that make the bay stand out.
Finally, reinstall any parts you took off. That includes the intake, battery, and hood liner. With everything back in, the engine bay should look brand new. The car will start like normal, with no issues or warning lights.
Conclusion
Although it takes some time and effort, cleaning the engine bay of your car is not difficult. Many DIY enthusiasts try to speed up the process with the use of a pressure washer, but there is a chance that it will do more harm than good. So, it is better to be safe than sorry.
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