Is it safe to wash your car engine?

Just as they occasionally wash their car on the outside and inside, some drivers sometimes choose to wash the engine. But here the opinions are divided: is it worth it or not to wash the engine? Are there any risks?

Why would you want to wash your car engine?

Because it also gets dirty. But what if it gets dirty? Do engines break because of the dirt?

Not necessarily. I mean there are cars all over the world that have never had their engine washed. Because, to be serious, the engine is somehow protected by the hood, does not rain on it, and mud or snow do not get to it. Maybe just a little dust deposits on it … Then why would you want to wash it?

The washing of the engine has a very practical purpose at its origin, but which, easily, has been transformed into something “fashionable”. Especially when it comes to car dealers or sellers who want to present “flawless” cars in front of people who do not know much about cars, who, if they see a clean engine, think that the car is technically perfect, aspect that I do not agree, topic about buying a used car that I covered

And there are also those passionate people who simply want to have a shiny engine because they love their car … But where is the practical part here?

In fact, washing the engine is, somehow, a necessity, not a pleasure. Specifically, on older cars, which are starting to leak various kinds of fuel, oil, liquids and so on. There are engines that, when you lift the hood, are wet everywhere. Like many other parts, they are all leaky, and the mechanic or even the owner doesn’t know where each leak comes from. So, before performing any mechanical work, it is good to know what we are facing.

This is where the engine washing comes in from a practical point of view. You want to get rid of leaks, you want to have the engine dry, no more oil leaking and smells inside, like a new car. But to identify what to do, it is compulsory to get rid of all the mess.

In time, the liquids leaked from the engine mixed with dust formed, in some cases, thick layers of calamine and a disgusting layer of dark dirt, especially in older vehicles. An engine wash is done with active solutions, which will degrease all these areas and leave the engine clean as new.

Using an engine degreaser? Of course!

There are plenty of brands of degreaser to choose from. The degreasing spray should be used from the bottom to the top to ensure complete coverage.

Most degreasing solutions come in the form of a spray, so this operation is simple and easy to do. What we need to know is that the degreaser does not have to reach the painted surfaces. At the same time, the degreasing solution should not be removed immediately, it should act for several minutes

Therefore, the engine washing is done to identify some technical problems, so that we know which gaskets to change, which seals to replace. We clean the engine, drive a few hundred kilometers and go back to work, seeing precisely where the leaks are, and the mechanic will know exactly what to change.

But how do you wash a car engine?

I hear different opinions, from the pressure wash directly to the engine, to the detailed aspects of each part under the hood. In fact, washing the engine is not easy at all, if you want to do it “by the book”. First of all, you need some powerful, degreasing active solutions that will remove even the oldest and most persistent oil stains. And you will need pressurized water, not huge, but a hose with reducer is ideal. Plus some clean brushes and carpets.

To begin, it is mandatory to disconnect the car battery. Otherwise, we risk having problems or doing some short circuits.

The first step in cleaning the engine compartment is to remove excess garbage under the engine hood, grill and possibly the air vents. This can be done very easily with the help of compressed air, if possible, or with a cleaning brush.

Using an aluminum foil is better because it can easily be molded onto the engine components that need protection during the washing process. Due to the molding, the aluminum foil will not obstruct the eyesight and is easier to use than plastic bags and masking strips.

The second step in washing an engine is disassembling the plastic elements that cover the top. Those are the wiper grille, the protective caps, the air filter housing, and so on. Using a spray bottle, the active solution splashes everywhere, both on the engine itself, as well as on the flame retardant wall or its attachments.

When applying degreasers, it is best to start with the bottom of the engine compartment, as this will reduce the risk of staining with degreasers. Important to know for car owners is that degreasers can remove wax from the car. If you mistakenly spray on the car wings, you will need to re-apply the wax to those areas.

Depending on the amount of dirt accumulated, allow the degreaser to act for about 3-5 minutes. Another useful tip is to not allow the degreaser to dry in the engine compartment. If the engine compartment is not that dirty, you do not need to use a brush. If the engine has a higher degree of dirt, you can use a brush with a long handle and a wash solution to have an extra cleaning power.

Leave it to act, until the dirt dissolves. Be careful to the dosage of the active solution, because in a  too high percentage mixed with water it will corrode the aluminum and the rubber, but in the right dose, it will only remove the dirt.

Insulation of electrical parts, if exposed, follows. So safety boxes, computers, relays, etc. The alternator or electromotor does not require insulation before the final rinsing, although many cover them with plastic bags or foil.

In older cars, we can cover the distributor cap or other electrical parts exposed. Otherwise, with the water hose, we can rinse directly without fear that something will break. If we see that oil, where there was a thick layer of deposits, has not been removed, we resume the process and leave in those areas the active solution to act more, and we can help with brushes. Then we rinse well again.

When to wash your car engine?

Ideally, engine washing is done when outside is over 20 degrees Celsius,68 F, because, ideally, you must leave the car at least 24 hours before connecting the battery again, to ensure that the water is depleted and that there is no risk of a short circuit. If there are a few plugs in sight, we can disconnect them and remove the water from the inside, if any.

If we are real professionals, it is good to blow all the washed areas with a compressor to make sure we have removed the water. So when we see that the engine is dry, we can connect the battery. And where there are still wet areas, we can use a cloth.

After the engine is dry and clean, we can start the car. If we have no error codes on board and if everything works, the drying has been completed. It is good at this moment to drive the car for about 30 minutes so that the engine warms up and evaporates the last traces of water.

If your goal is to wash the engine to see the different leaks then, after washing, you can travel for a few days, weeks, then take the car to a service so that the mechanic can identify exactly what gaskets, seals or bearings that need to be replaced, and what actions should be taken.

Finally, if we repair all these elements that caused leaks, we could have a dry engine that, in the future, will be dirty only with dust, easy to clean and, why not, easy to maintain.

Scroll to Top