The Best Way To Clean A Greasy Engine Bay
We may receive a commission on purchases made from links.
When it comes to cleaning, that screaming engine under the hood deserves the same level of care as the rest of your car. Your car's motor and other related components in the engine bay are a mishmash of metal and alloys, wiring, plastic, ECUs, and other electronics, making them susceptible to heat, dust, moisture, and dirt. In some cases, the engine develops oil leaks from worn gaskets and seals, which usually leads to an ugly, oily, greasy mess of an engine bay.
Perhaps your first instinct is to attack the debris with a hose and a cleaning brush, but remember that the engine bay has wiring and electronics. The alternator, for instance, keeps the battery charged and powers electrical components — which is why your car will eventually shut down if the alternator fails. As it turns out, the alternator hates water, and dousing it with a hose is like signing an expensive death sentence that could cost hundreds to replace.
For us, the best way to clean a greasy engine is to take the waterless route, at least for some areas that are heavily smudged with thick grime. Start by vacuuming in and around the engine bay to suck out loose dirt, leaves, rodent droppings, and other nasty stuff. Next, grab some cleaning wipes to remove the lumps of grease around the engine and repeat if necessary. The last step is to grab a waterless engine cleaning spray, like the Kraken Bond Engine Cleaner Spray or Zep Cherry Bomb Auto+ Degreaser & Cleaner. Spray liberally, allow to dwell for five to 10 minutes, and wipe off with a microfiber towel. Repeat for heavily stained surfaces.
Nobody's stopping you from hosing down the engine bay and washing it like dirty clothes, but you've got to at least do it right. Get a plastic garbage bag and use it to cover the ignition coils and any ECUs or computers that may short out when wet. Go ahead and wrap the alternator with a plastic bag, too, and don't forget the air intakes, the distributor (when applicable), and the battery. Speaking of the battery, you should go ahead and clean the battery terminals before the actual degreasing part.
It may be tempting to use dish soap as a homemade alternative to commercial engine degreasers, and concentrated dish soap may be viable for removing grease and grime on engine parts, but there are two problems with this method. First, dish soap can be too harsh for plastic and rubber and may worsen degradation. Second, those foamy dish soap suds must be rinsed off with water, which may not be ideal if the area is near sensors, wiring harnesses, and other electronics.
You can use water and dish soap in a pinch, but be mindful to rinse or wipe off the liquid immediately. If you insist on using dish soap, you should apply a trim restorer at the very least. The Slick Products Multi-Surface Shine & Protectant Spray can help restore rubber, plastic, and vinyl. For light grease stains and spot cleaning, the Armor All Original Protectant Wipes are useful for cleaning plastic and rubber underhood components while adding shine. Combined with waterless degreasers, you can safely clean and restore a greasy engine bay without risking damage to sensors or causing misfires.
