It’s good practice to degrease the engine bay of your car, SUV, 4WD or truck every six months at a minimum and preferably every three months to keep the build-up of grime to a minimum. This section contains everything you need to know about degreasing the engine bay of your vehicle with ease and lists the many benefits of a sparkling engine bay.
Use kerosene to degrease the engine bay…
An effective and economical way to degrease the engine bay is using kerosene (dispensed in a trigger-spray, plastic container) which is strong enough to dislodge dirt, grease and grime but mild enough that it won’t damage the components of your engine bay, whether metal or plastic.
Kerosene can be purchased in 4 litre (1 gallon) containers, making it more economically priced. This also ensures that you have a good amount of kerosene on hand to avoid running out too quickly. I try to purchase 12 litres (3 gallons) at a time for the year or two ahead, which beats buying only a small amount and then having to return to the hardware store later on to obtain more.
Don’t use harsh degreasers to clean the engine bay…
Be very wary about using stronger, purpose-built degreasers on your engine bay. These are available from automotive parts shops and are effective at cleaning oil stains off of concrete floors. Even purpose-built degreasers which have statements on their containers that they’re safe to use on engine bays may very well not be safe to use on engine bays.
When used on your engine bay, these stronger degreasers can easily react adversely with the metal coatings on the components inside your engine bay and ruin their appearance permanently. These stronger degreasers can also react with the painted surfaces of components of your engine bay such as the block of your engine or even the painted surface of the body of the vehicle surrounding the engine bay itself.
The safest degreaser to use is kerosene which will not cause any of this kind of damage to the components in your engine bay. It’s strong enough to remove the grease and grime but not harsh enough to damage the components of the engine bay.
The benefits of cleaning the engine bay…
The benefits of keeping the engine bay of your vehicle as clean as possible should not be underestimated and include the following:
It’s easier to spot damage in the engine bay…
It’s much easier to spot damage of any kind in the engine bay or anything that’s otherwise not as it should be if the engine bay is clean.
A clean engine bay is easier to work on…
An engine bay that is clean is cleaner to work on. There’s little dirt, grease and grime to make things really messy, which makes working on the engine bay more enjoyable. Let’s face it, the different fluids that exist in a motor vehicle hold enough potential for mess all on their own. It’s best not to let things be any messier than they have to be.
It’s easier to keep the vehicle’s automotive fluids clean…
There’s less likelihood of dirt, dust or any other contaminants entering an opening when checking or topping up fluid levels on the vehicle such as engine oil, coolant, automatic transmission fluid, brake fluid or power steering fluid.
Your mechanic will like and respect you better…
Your mechanic will like you better if you keep your engine bay clean, especially before taking your vehicle to your mechanic to have specific work carried out. A clean engine bay makes your mechanic’s job easier and more enjoyable. He or she will appreciate the effort you’ve made. You’ll find that your mechanic will treat you with respect, taking more time and care to answer your questions and inquiries.
It’s easier to change the spark plugs in a clean engine bay…
When you next need to change the spark plugs, it’s quicker and less time consuming to clean up the area around the plugs with kerosene (to minimise the likelihood of foreign matter entering the engine when the plugs are removed), when the entire engine bay is already quite clean.
Without this underlying standard of general cleanliness, don’t underestimate the potential of a piece of grit or grime in some obscure place in the engine bay to find its way into one of the combustion chambers through an open spark plug hole. This kind of foreign matter inside the engine can exacerbate wear in the engine and should be avoided.
Cleaning the engine bay prevents corrosion occurring…
Corrosion on the components in the engine bay is reduced because there’s little, if any dirt or grime to absorb moisture, trap it against the components and cause them to corrode. Leaving the engine bay in a dirty state for a long time will increase the likelihood that components in the engine bay will corrode. Corroded engine bay components are a definite example of something that will reduce the market value of your vehicle.
A vehicle with a clean engine bay has a higher market value…
A vehicle with a clean engine bay has a higher market value than the same vehicle with a dirty engine bay, all other things being equal. If you keep your engine bay clean, then when you come to sell the vehicle, you’ll be in a strong position to get a good price for it.
How to degrease the engine bay…
The steps involved in degreasing the engine bay of your vehicle are as follows:
- Make sure that the engine and transmission of your vehicle are cold and that the vehicle has not been driven for several hours. Failure to do this could result in expensive damage to your vehicle which may even render your entire vehicle useless. The best time to degrease the engine bay of your vehicle is in the morning when the vehicle has not been driven since the previous day.
It’s critically important that the engine, transmission, differential and all other metal components are cold because degreasing the engine bay involves hosing the engine bay with water in a later step. If any components such as the engine or transmission are hot or even warm, the cooling effect of the water from the hose can easily cause the section of the metal component being hosed to cool and contract more quickly than other sections of the same component which can result in the metal component warping or even cracking. This is expensive, debilitating and discouraging damage which is best avoided.
- Put on some chemical-resistant gloves, which are available from your local hardware store, to protect your hands from the kerosene. Kerosene is a hydrocarbon which is hazardous to your health. It should not be allowed onto your skin, because it can be absorbed very easily into your bloodstream through your skin. It’s a good idea to also use barrier cream on your hands for further protection from the kerosene.
Pour kerosene into one of those inexpensive, trigger-spray, plastic containers, which are available from your local hardware store. It’s a good idea to purchase several of them at once.
Here’s a simple tip. Don’t pour the kerosene all the way to the top of the plastic container because you still need to screw in the trigger-spray which will displace some kerosene and make it spill out, causing a mess. Rather, leave some space at the top of the plastic container so that you can screw in the trigger-spray without displacing any kerosene.
- Still with the chemical-resistant gloves on to protect your hands from the kerosene, spray the kerosene liberally over the cold components of the engine bay, including the fuel injection rail of the intake manifold or the carburettor, the brake system master cylinder and the steering rack which is usually bolted on to the front of the firewall down low at the back of the engine bay.
You should avoid directly spraying electronic components in the engine bay with kerosene such as the distributor, in order to avoid damaging them, especially sensitive electronic components such as computerised circuits that control different systems on the vehicle. Although it’s possible to spray kerosene on electronic components and later wash them down with water without causing damage to them, it’s really best to avoid this altogether because the possibility exists of damaging them.
If you want to make absolutely sure that you don’t damage any electronic components in the engine bay when degreasing it, you can cover them over with plastic bags secured with rubber bands before spraying the engine bay with kerosene.
It’s also best to avoid spraying kerosene on suspension-related components on either side of the engine bay which may be lubricated with grease, such as the tie-rod ends of the steering rack which meet with the steering knuckle arms onto which the disc brake callipers are mounted. The kerosene may degrease these components which actually need to be lubricated with grease to function properly, so it’s best to avoid spraying them.
- Let the kerosene soak in for ten minutes. Over this time it’s being absorbed into the dirt, grease and grime on the components in the engine bay and freeing it up.
- After ten minutes has passed, hose the engine bay down with water with moderate but not strong pressure, being careful to avoid directly hosing any electronic components such as the distributor (especially sensitive components such as computerised circuits). Hosing the engine bay with water washes the kerosene away as well as the dirt, grease and grime that the kerosene has displaced. Your engine bay will look clean and sparkling once again!
- Stand around for a couple of minutes admiring your clean, sparkling engine bay. (I always do this. It’s irresistible!) On the other hand, if the engine bay is not yet sparkling and clean because it had a substantial build-up of dirt, grease and grime in it, it would be a good idea to return to step 2. above and give the engine bay a second spray of kerosene. This should be enough to clean most engine bays.
- Remove any plastic bags that were used to protect electronic components in the engine bay.
- Turn the engine on and let the vehicle idle for ten minutes in order to build up heat in the engine bay. This is necessary in order to dry out the water remaining all over the engine bay and to ensure that everything is working as it should be after the engine bay has been given this drenching with water.
- Pour any kerosene remaining in the plastic spray-container back into the container of kerosene from which it was poured.
Rinse the spray-container out with water, then fill it up again with water and pump that water through the spray attachment for at least thirty seconds to get rid of all traces of kerosene in the spray attachment. Failure to follow these steps will result in your $3 spray-container and attachment being rendered useless by the kerosene in ways that I don’t understand. I think that the kerosene softens up the plastic components or the seals in the trigger mechanism so that it won’t spray properly any more.
What’s at stake here is not the small cost of a replacement spray-container but the larger cost of time involved in going to the hardware store to obtain a replacement spray-container. It’s also really annoying to go to degrease your engine bay and find that the $3 spray-container that you used last time with kerosene doesn’t work any more because of the kerosene you left in it.
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