O motor faz muito barulho.

In Portuguese, singular countable nouns usually need an article or some other determiner. So o motor means the engine.

Saying just motor by itself would usually sound incomplete in a normal sentence. Portuguese uses articles more often than English does.

Examples:

• O motor faz muito barulho. = The engine makes a lot of noise.
• Um motor faz muito barulho. = An engine makes a lot of noise.

Faz is the he/she/it form of the verb fazer in the present tense.

Here, the subject is o motor, which is a singular it, so Portuguese uses:

• eu faço
• você/ele/ela faz
• nós fazemos
• eles/elas fazem

So:

• O motor faz muito barulho.
• If it were plural: Os motores fazem muito barulho.

Yes. Fazer barulho is a very common expression and matches English quite closely.

• fazer = to do / to make
• barulho = noise

So fazer barulho means to make noise or to be noisy, depending on the context.

Examples:

• As crianças estão fazendo barulho. = The children are making noise.
• Esse ventilador faz barulho. = That fan makes noise / is noisy.

Here muito means a lot of, not many.

Barulho is being treated as an uncountable idea here, like noise in English. So Portuguese uses the singular noun:

• muito barulho = a lot of noise

If you say muitos barulhos, that would mean many noises / many different sounds, which is less natural in this situation.

Compare:

• O motor faz muito barulho. = The engine makes a lot of noise.
• Ouvi muitos barulhos durante a noite. = I heard many noises during the night.

Because barulho is a masculine singular noun.

When muito works like an adjective or quantity word before a noun, it agrees with that noun:

• muito barulho (masculine singular)
• muita fumaça (feminine singular)
• muitos carros (masculine plural)
• muitas pessoas (feminine plural)

Since barulho is masculine singular, the correct form is muito.

Because muito barulho already works as a quantity expression: a lot of noise.

In Portuguese, you do not normally say faz muito o barulho here. That would be incorrect.

You can think of muito barulho as one chunk:

• fazer muito barulho = to make a lot of noise

Yes. That is also correct, but it is structured differently.

• O motor faz muito barulho. = The engine makes a lot of noise.
• O motor é muito barulhento. = The engine is very noisy.

The first uses a noun phrase (barulho = noise). The second uses an adjective (barulhento = noisy).

Both are natural. The original sentence is especially useful because fazer barulho is a very common everyday expression.

Both can refer to noise, but barulho is more common in everyday speech.

• barulho = everyday noise, often general or noticeable sound
• ruído = more technical, formal, or specific noise

For example:

• O vizinho faz muito barulho. sounds very natural in daily conversation.
• Há muito ruído no motor. sounds more technical, like something a mechanic or report might say.

In normal conversation, barulho is usually the safer choice.

It can do both, depending on context.

Portuguese present tense often covers:

1. general/habitual meaning
   
   • O motor faz muito barulho. = The engine is noisy / generally makes a lot of noise.
2. what is happening now
   
   • O motor faz muito barulho agora. = The engine is making a lot of noise now.

Context tells you which meaning is intended.

Then both the article and the verb change:

• O motor faz muito barulho.
• Os motores fazem muito barulho.

Changes:

• o → os
• faz → fazem

The phrase muito barulho stays the same because it still means a lot of noise.

A simple approximate pronunciation is:

oo moh-TOR faz MOON-too bah-RU-lyoo

A few helpful notes:

• motor has stress on the last syllable: mo-TOR
• faz sounds roughly like faz, with a clear z sound at the end
• muito in Brazil is often pronounced close to MUN-too or MOON-too, depending on region/speed
• lh in barulho is like the lli in million for many English speakers, though not exactly the same

A more refined approximation: u mo-TOR faz MUI-tu ba-RU-lyu

Not much in this sentence if you want it to sound neutral and natural.

The standard order is:

• O motor faz muito barulho.

Something like O motor faz barulho muito is not natural.

Portuguese usually keeps muito directly before the noun here:

• faz muito barulho

You can move things around for emphasis in other contexts, but for a basic statement, the original order is the best choice.

Yes, motor is a masculine noun in Portuguese, so it takes masculine articles and adjectives:

• o motor
• um motor
• motor barulhento

That is why the sentence begins with O motor and not A motor.

Yes. That is perfectly correct.

• O motor faz barulho. = The engine makes noise / is noisy.
• O motor faz muito barulho. = The engine makes a lot of noise / is very noisy.

Adding muito makes the idea stronger. It emphasizes that the noise level is high.