Washing A Car With A Hood Scoop – What To Consider

Hood scoops may seem tricky to deal with. Especially when washing a car. Water in the engine bay is probably the biggest fear of car lovers. There is a reason for that: filters, electronics, etc. This article is about the most important things to consider when washing a car with a hood scoop.

Here are some tips to settle your doubts about washing a car with a hood scoop:

  • Control the water flow
  • Adjust your washer pressure
  • Regulate your hose water jet
  • Don’t forget about the engine temperature
  • Water temperature is important
  • Dry the engine compartment afterward
  • Cover the hood scoop
  • Consider a waterless wash

Control The Water Flow

You don’t need that much water to wash your car. So it doesn’t make any sense to turn the tap on full blast. First of all, you’ll make a mess: everything will get wet. Secondly, extra water will not speed up your washing in any way but will only increase your bills and water consumption. 

This advice is especially relevant if you wash in the backyard, or near the garage. In that case, you are more likely to use a hose. Adjust it to medium or weak beforehand, and then open the water tap halfway. If you think the water flow is too weak, first increase the pressure on the hose and then adjust the water tap.

Adjust Your Washer Pressure

The best pressure to wash your car is around 1000 — 1500 PSI (pounds per square inch). Set your pressure washer to 1000 PSI as a good starter. Yet, you should bear in mind another important factor called GPM. It stands out for gallons per minute, referring to the amount of water used.

But there is a third  — even more important — parameter. It’s called cleaning power and is usually measured in CU (cleaning unit). Cleaning power is simply a multiplication of PSI and GPM. To wash a hood scoop safely, you should utilize higher pressure and a lower amount of GPM. This way you’ll use less water. Thus, protecting the engine bay from water leakage (there is almost no water to sneak under the hood). It’s recommended to use cleaning power around 2.000 CU. With 1200 PSI and 1.5 to 1.6 GPM. 

Regulate Your Hose Water Jet

A certain amount of water is bound to get under the hood, and that’s okay. But it’s important to consider HOW the water gets there. You can stand close to the car and point the hose right at the hood scoop, then all the force of the pressured water will hit your engine bay directly. 

On the other hand, you can take a couple of steps back, turn around a little bit. The main thing here is that the water will stop going straight into the engine. It’ll take longer for the jet to get under the hood. Also, the force of the pressure will be lower if the water is applied at an angle (instead of direct exposure). Take this fact into account when washing your car.

Additionally, you can get some nozzles to spread the brutality of the pressure. The market offers a whole variety of nozzles, some of them equipped with an automatic water flow blocker. 

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Don’t Forget About The Engine Temperature

Have you heard of a phenomenon called thermal shock? It happens when two bodies with unalike temperatures touch each other. For example, water and a hot engine. As a result of such a “date”, you risk damaging the engine (not only the engine, the paint could also be affected).

Remember how unpleasant it is to leave a warm house and go outside in cold winter. Now imagine that you have to jump into the freezing water. Approximately the same shock is felt by the car engine. But much worse… because it didn’t go through many years of evolution as a human being.

To wash your car with a hood scoop safely, make sure you haven’t used the vehicle for at least a couple of hours. That way, the engine temperature will be about the same as the water temperature during the wash. 

If you have used the car, give it some time to cool down. This is especially true in the summer, when the car gets extra heat from the sun and dry air.

Water Temperature

Another important parameter not to forget. For summer washes use hot water; as for the winter, you better stick with moderately hot water (to avoid the shock mentioned above)

In general, the water temperature should not be very different from the ambient temperature. Try to use water that is 85°F to 105°F. If you don’t have a way to measure the temperature, rely on your senses. Touch the body of the car, or the engine if the car hasn’t been used for a while. After that, fill a bucket with water and dip your hand into it. The temperature sensation should either be the same or very similar. If you can’t keep your hand in the bucket of water for longer than 5 seconds, then it is too hot.

Dry The Engine Compartment Afterward

You’ve washed the car, checked whether it’s clean, and dried the body. Now it’s time to lift the hood and dry the engine bay. Use a thick and soft microfiber to remove excess water from the engine compartment. Pay special attention to the filters and the area near the battery. This is where water sneaks most often. Then go over the back of the hood scoop with a rag to remove any residual water. 

While a little extra liquid won’t hurt the engine right away, water can accelerate chemical processes. The most unpleasant of these is corrosion. Therefore, make sure to dry the engine compartment thoroughly. Because corrosion is not a risk you are willing to take.

Cover The Hood Scoop

If you want to minimize the amount of water entering the engine compartment, simply close the orifices in the hood scoop. This can be accomplished by several methods.

  • Waterproofing tape: It is widely used in many areas: from households to construction and plumbing repairs. Therefore, you can have zero doubts in terms of the reliability of the method. Of the minuses, you can note the higher cost compared to other methods. Just tape up the entry orifices of a hood scoop. For greater certainty, you can apply tape in 2 layers. 
  • Garbage bags: You can place a garbage bag directly into the engine compartment. Do this to protect the engine parts. A bag will play the role of a protective reservoir. This way, the water will get under the hood but will not contact the engine. A great way to protect the bay. By the way, you can combine bags with waterproofing tape.
  • Towels: The easiest and cheapest method of protection (although its effectiveness is limited). A few towels over the hood scoop will be sufficient to absorb the excess moisture and reduce the amount of water penetrating the engine. However, towels can absorb a relatively small amount of water. Plus, they don’t sit as tight as tape.

If you care about the engine but don’t want to deal with all this waterproof stuff, there is a way for you. It’s called waterless wash.

Consider a Waterless Wash

Innovations in the world of detailing make life easier. A waterless wash is a special type of washing that does not require water. The essence of the method is to apply special cleaning chemicals to the car body. They are usually sold either as a spray or as a concentrate. There are many products with very different compositions and additives, but their one essence is the same  — cleaning without water.

Of course, if there is no water, you have no chance of getting the engine wet. The advantage of this method is the increased safety of the engine. If you live in a place without permanent access to water, high-pressure washers, and other equipment, then this method is a no-brainer for you.

To perform a waterless wash, you’ll need a сleaning formulation and a few thick, soft microfiber cloths. After applying the product to the car, all you need to do is wipe it off with a microfiber. No risk to the engine.

What If Water Leaks Into The Engine Compartment?

Nothing will happen to the engine if a little water gets under the hood. It often happens even with cars without an air intake. For example, when it rains. Most car components can handle water, so water under the hood is not a big problem. 

However, too much water can cause such a phenomenon as hydrolock. Simply put, water getting into the engine stops the pistons from moving. That’s why it’s not advisable to lift the hood during a wash.

If you want to know more about hydrolock, and what to do if it happens, read this article.

Key Takeaways

  • Water won’t harm your filters
  • The engine only suffers if almost fully submerged in water
  • You can tape the scoop to prevent water leakage under the hood
  • A garbage bag can help with the engine water protection
  • A waterless wash is the safest way to treat cars with a hood scoop
Jan-Lucas Ganssauge
Jan-Lucas Ganssauge