Is It Ok to Wash a Car’s Engine? The Truth & the Lies

For this category of vehicle users and school of thought, opening the hood of a vehicle to clean or wash the engine doesn’t make sense.

Some of these vehicle owners go as far as claiming that washing an engine isn’t without any obvious benefits but causes numerous challenges, such as a no-start condition after the wash.

But, in truth, is washing an engine bad? Should you strive to keep your hood immaculately clean or drive with the grime and dirt of years simply accumulating on the metal and plastic parts that make up your engine?

Here are the answers you’ve been waiting for, devoid of the fluff and lies.

‘Is Washing An Engine Bad?’

Washing a car’s engine and cleaning the hood of a vehicle isn’t bad in itself; however, like many things in life and the automotive world, it has pros (when done well) and also potential challenges, when not done right.

This is so for several reasons, chief amongst which include the presence of several electrical components that don’t go well with fluids (such as water).

Done right, cleaning an engine bay (and by extension, an engine) is a ritual that doesn’t only look good but adds value to a vehicle besides presenting many on-the-spot advantages that I’ll mention soon.

So, what are these advantages? What are the gains of keeping a clean engine and hood, generally?

The Advantages of Washing an Engine & Keeping a Clean Hood

There are several advantages to washing an engine and keeping a clean hood, generally. Here:

• First, a clean hood compliments the overall cleanliness of a vehicle. Think of it as wearing newly washed and pressed clothes without taking your bath.
• Second, if you’re interested in selling the vehicle at a later date, a clean hood will make a strong case for how much you have cared for the car and this will translate, immediately, to a better offer.
• Third, a clean/spotless hood will aid in detecting leaks and other challenges in the hood as soon as they occur. On the other hand, a hood that is covered with grim and grease will give you the maximum challenge when such a leak or compromise occurs.
• Finally, a clean hood will help a vehicle run more efficiently, in most cases. For instance, an engine covered with mud has added weight to it, all of which must use engine power, derived from gasoline/diesel to aid movement. If the mud is in the way of belts, fans, or other moving parts, the immediate risk of damage to parts is better imagined than articulated.

With the challenges of a dirty engine bay spelled out, how often should you clean your vehicle’s engine?

How Often Should You Clean Your Vehicle’s Engine?

How often you should clean your vehicle’s engine is a product of how quickly the engine gathers dirt, which in turn is largely determined by where you drive, how sealed the engine is, and importantly, how frequently you drive (or expose the engine).

As a general rule of thumb, if you live and drive in the tropics where dust particles are an indispensable part of the air (and mud your ally when the dust subsides), your best bet is washing your engine at least, once a month.

If you live in the temperate parts of the world where your concerns aren’t dust or mud, a timeline of between six (6) months and a year is a great starting point.

So, what should you wash your engine with? Water?

Can You Wash a Car’s Engine With Water?

Yes, you can (and should) wash a car’s engine with water. If this is practical, keep it only at the water level and avoid introducing any other liquids into your engine bay in the name of an engine wash.

Why?

Some folks swear by diesel/gasoline as the ultimate ‘resource’ for engine washing, citing their less ‘offending’ properties and propensity to do better than water, at the base level.

This makes sense, in theory. However, in practice, these are fluids with an unfriendly flash point, making the risk of a fire in the engine bay after their use a potent concern.

Other ‘special chemicals/formulations’ for the use of cleaning the hood of a vehicle may react negatively with other vehicle components and in the long run, cause damage, especially for makes with a lot of plastics in the hood like a typical BMW.

If your vehicle isn’t stock again (especially regarding the engine), this complicates matters and makes things even worse…best to leave out all uncertainties and simply use old, plain, harmless, reliable water.

So, should the water for washing an engine be fired through a pressure washer, or should things be done manually?

Can You Pressure Wash a Car’s Engine?

Pressure washing a car’s engine is a bad idea and it’s what I generally don’t do or counsel car owners to do.

The reason is that water, ejecting at pressure, will easily get into unintended places and cause challenges that weren’t part of the initial engine washing plan.

With that said, I ALWAYS HAND WASH any engine that comes my way; leaving pressure washers for the body and underneath, only.

With the above said, this doesn’t mean pressure washers in the hood are completely bad or should be avoided. If you have a pressure washer that features an adjustable jet (and you know what you’re doing), you and your engine will be good.

What Precautions Should Be Taken When Washing an Engine Bay?

In washing a car’s engine, the following precautions should be taken to ensure that the vehicle starts (and runs fine) after the wash:

• The alternator should be covered with waterproof material during the wash and hand-cleaned with a wet rag after the wash itself.
• The fuse box should be covered and cleaned after with a wet rag.
• The MAF should also be covered and cleaned after, manually.
• Be careful and avoid launching water directly at the ABS pump.
• Do not let water get into the engine oil cover.
• Cover every other electrical component (vehicle dependent) likely to be compromised when exposed to water.

With these precautions, you should be okay – and successfully clean your engine bay without any incidents, getting the vehicle to start and run fine while (overall) keeping a clean hood underneath.

Wrap-Up: Should You Clean Your Vehicle’s Engine?

There are many advantages to washing an engine and keeping your engine bay spotless. A dirty, grime-infested engine does no one any good and if anything, causes indirect harm, in the long run.

However (and this is very important), the business of washing an engine isn’t something for the novice or amateur…and, unlike regular car washes, there are dire consequences when got wrong.

If you’re not sure how to go about cleaning your engine bay, engage a professional who knows their way about an engine.

Remember, a dirty engine may still start and get you to your destination…however, an engine washed wrong will almost certainly NOT start, in the first place!

Love the Above? Subscribe for More