A correia e o óleo do motor precisam ser verificados.

Because the subject is compound: a correia e o óleo do motor refers to two things.

• a correia = the belt
• o óleo do motor = the engine oil

When two nouns are joined by e (and), the verb normally goes in the plural:

• A correia precisa... = The belt needs...
• O óleo precisa... = The oil needs...
• A correia e o óleo precisam... = The belt and the oil need...

So precisam is the correct form.

Because the phrase includes one feminine noun (a correia) and one masculine noun (o óleo). In Portuguese, when you have a mixed-gender plural group, agreement normally goes to the masculine plural.

So:

• a correia → feminine singular
• o óleo → masculine singular
• together → verificados (masculine plural)

If both nouns were feminine, you would use verificadas.

For example:

• A correia e a mangueira precisam ser verificadas.

It is a passive infinitive structure.

• precisar + infinitive = to need to do something
• ser verificado = to be checked / to be inspected

So:

• precisam verificar = they need to check
• precisam ser verificados = they need to be checked

In this sentence, the belt and the engine oil are receiving the action, not doing it. That is why Portuguese uses the passive idea to be checked.

Because de + o contracts in Portuguese:

• de + o = do
• de + a = da
• de + os = dos
• de + as = das

So:

• óleo do motor = oil of the engine / engine oil

This contraction is required in normal Portuguese.

By default, it most naturally modifies óleo only.

So the most likely reading is:

• a correia = the belt
• o óleo do motor = the engine oil

In other words: the belt and the engine oil need to be checked.

If you wanted to make it clear that the belt is also of the engine, you would usually say something like:

• A correia do motor e o óleo precisam ser verificados.
• A correia do motor e o óleo do motor precisam ser verificados.
  (more explicit, though a bit repetitive)

Portuguese uses definite articles much more often than English does.

So Portuguese often says:

• a correia = the belt
• o óleo = the oil

even when English might prefer a more article-light style depending on context.

In technical or maintenance language, using the articles here sounds natural and standard.

Correia literally means belt or strap. In an automotive context, it usually means some kind of belt in the engine system, such as:

• drive belt
• timing belt
• fan belt

The exact type depends on context. By itself, correia does not specify which belt.

If the sentence needed to be more specific, Portuguese might say:

• correia dentada = timing belt
• correia do alternador = alternator belt

Not exactly. This is a very common false-friend issue.

In Portuguese, verificar often means:

• to check
• to inspect
• to examine

So in this sentence, ser verificados is best understood as to be checked or to be inspected, not necessarily to be verified in the narrower English sense.

That is why a natural English translation would usually use checked.

Yes, in Brazil, checar and checado are common and widely understood, especially in informal, technical, or everyday speech.

So these are possible:

• A correia e o óleo do motor precisam ser verificados.
• A correia e o óleo do motor precisam ser checados.

However, verificados often sounds a bit more formal or standard in writing.
Checados sounds more informal and closer to spoken Brazilian Portuguese.

Depending on context, you might also hear:

• inspecionados = inspected
• conferidos = checked/confirmed

In Brazilian Portuguese, the normal pattern is:

• precisar + infinitive

So:

• precisam ser verificados

is the expected structure.

The version with de before the infinitive (precisam de ser...) is associated more with European Portuguese and is not the usual Brazilian pattern.

So for Brazilian Portuguese, this sentence is perfectly natural.

Yes. The given sentence is passive: need to be checked. A more active version would mention the person doing the checking.

For example:

• Você precisa verificar a correia e o óleo do motor.
  = You need to check the belt and the engine oil.

• O mecânico precisa verificar a correia e o óleo do motor.
  = The mechanic needs to check the belt and the engine oil.

Portuguese uses both active and passive structures, just like English. The passive version sounds especially natural in instructions, manuals, and maintenance recommendations.

A rough pronunciation guide is:

a ko-RAY-a ee oo OH-lyoo do mo-TOR pre-SEE-zum ser veh-ree-fee-KAH-doos

A few useful notes:

• correia is usually pronounced roughly ko-RAY-a
• óleo has stress on the first syllable: OH-lyoo
• precisam sounds roughly like pre-SEE-zum
• verificados has stress on ca: veh-ree-fee-KAH-doos

The exact sound will vary by region, but that approximation is close enough to help a beginner.

Yes, very natural.

It sounds like something you might read or hear in:

• a maintenance checklist
• a repair manual
• a mechanic’s recommendation
• a vehicle inspection report

It has a slightly formal, technical tone because of verificados, which fits that context well.