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Can You Open Car Hood in the Rain?


Engine breakdown in the rain is a common thing most drivers experience. You may want to fix the problem, but you aren’t sure if it’s safe.

However, opening the car hood in the rain is possible but should be done carefully. You should prevent the car engine from getting wet.

You can do this by covering using an umbrella or piece of polythene when opening the car hood. When water gets into the engine, it causes hydrolocking and eventually breaks down.

This article highlights the effects of water in the engine and possible steps to take once you find traces of water in your engine.

What Is the Effect of Water on the Engine?

You do not need a mechanic to tell you water does not belong in a car’s engine. Once rainwater gets into the engine, it can lead to compression issues because there is no way out.

car into heavy rain water

This water can causes bending to piston rods and most likely break. The chunk may come out in the process through the bottom or the top of the engine, resulting in an engine failure.

However, this is not the only problem caused by rainy water; too much water in the engine can also contaminate with transmission fluid or oil. These issues are more dangerous and cause malfunctioning of your engine.

Below, I’ll explain possible disasters and ways to prevent motor breakdown once water gets into your engine.


Hydrolocking is the failure of engine performance due to water present in the cylinder. Fuel must burn for the engine to produce horsepower to drive a car.

To optimize fuel burning, the piston must compress air in the cylinder. However, the fuel bunt is in the gaseous state, making it easy for the piston to compress. Unfortunately, it’s too hard to compress water.

When water finds its way into the cylinder, as the crankshaft turns the piston, it’ll find water to compress other than an air-fuel mixture.

Unfortunately, compressed water has nowhere to go. This energy must transfer somewhere. Now what follows can be a disaster. The engine parts may explode, or if you are lucky enough, the parts will stop functioning.

The power of the engine can cause breakage to the connecting rods. The broken connecting rod can cause holes in your car’s engine.

However, the hydrolocking system may start functioning after a long time of rebuilding and a lot of money expenditure. So to prevent damage to your car engine, do not open the engine system while it’s raining.

Breakdown of Petrol, Oil, or the Transmission System?

Under heavy rainfall, with the hood open, your engine might let in water. How can you know your engine lets in water? Here is what you need to do.

Before igniting the engine, taste for the presence of water by checking the oil dipstick. Because water has a higher density than oil, it should occupy a lower position than oil.

Be sure your engine is contaminated whenever you find water traces at the end of the oil stick. You need to drain away and replace the oil to remove the water. To be safer, remove and clean the oil pan.

Electrical Faults

Water can lead to electrical faults. Water and electricity do not interact well. Heavy rain can prevent an electric spark from reaching the plug.

No electricity gets to the spark plugs whenever the distributor caps get logged with water. Also, the current flow to various staff parts under the hood gets controlled by fuses.

When these fuses get contaminated with water, you’ll notice some chaos in the engine. Whenever your fuse box gets contaminated with water, various parts of the car will not coordinate well.

Engine Rust

Rusting depends on the location you are in. Places with heavy atmospheric pollution have an adverse effect on the type of rain in that area.

Acidic rainfall is more significant in these areas. If you didn’t know, then get to know, acid rain accelerates rusting process. Slip of rainy water results in engine rusting.

In such areas, when you get stuck on the road and want to open the hood, the choice is yours.

What Should You Do if Water Enters the Engine?

Water can cause severe damage to your car engine. A good example is hydrolocking. Whenever you find water in your engine, look for means to drain it.

Without doing so, you may need to buy a new engine or spend a lot of money fixing it. More of all, if you need to save cash, avoid opening your car hood while in the rain.

Whenever water enters your car engine, here is what you need to do:

Make it out of the rain and find out if the engine stalls. Whenever you find the engine stalling, there is the possibility of a hydrolocked system. under such circumstances, do not fix the problem with the rain.

Wait for the rain to stop or find somewhere out of the rain and handle the situation.

Whenever you open the hood in the rain while closed after that, and the engine refuses to start, here is what you need to do. Leave the car for some time so that water can dry out from the engine’s temperature.

After the car has cooled, check for water contamination on the transmission fluid or oil. If they are contaminated, drain and replace. Note: avoid long distances without checking for water contamination.

When checking for water contamination, start by putting off the battery. Use a dipstick to check the contamination of the transmission fluid and oil. Whenever there is water, drain and replace. Let professionals wash the fuel tank where you can’t.

Check the fuses. How will you do this? You check the fuses by turning on the engine. If the fuses are OK, there will be no chaos in the car electronics.

Also, a place to check is the engine cylinders. Water in the cylinder destroys its performance. When too much water drains on the engine, consult a mechanic to drain the water. Besides water causing rusting of the engine parts, a mechanic can help to prevent this.

Luckily, manufacturers have come up with vacuum cleaners to help us remove any traces of water under the hood or any parts of the car where cleaning can be difficult.

What Should You Check After Opening the Hood in the Rain?

Start and listen to your engine- whenever you hear an unusual sound in your engine, there must be a problem. Take a look at the engine and fix the problem as soon as possible.

Car in the rain with an umbrella over the hood

In cases where you find it hard, consult a mechanic. When this problem persists for a long time, you will incur more expenses in fixing it or may end up buying a new car engine.

Inspect fuse box- check the fuse box whenever there is a malfunctioning of the car’s electronic appliances. Water in the fuse box can fry out the entire electrical system of your car. In case you find water traces dry them up to prevent damage.


It is possible to open the car hood and fix any problem. You should, however, prevent too much water rain on the car’s engine as this can cause harm.

Rainy water causes rusting of the car’s engine. The rusting process accelerates when acidic gases in the atmosphere pollute the rainwater.

Whenever water finds its way into the engine system, drain or consult a mechanic to perform the task of removing it. In oil or transmission fluid contamination, you have to drain or replace it.

To stay safe from all these problems, do not open the hood while raining.

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