A válvula perdeu ar.

A is the feminine singular definite article, meaning the.

So:

• a válvula = the valve

Portuguese nouns have grammatical gender, and válvula is feminine, so it takes a, not o.

Válvula is the standard Portuguese word for valve. It is a feminine noun:

• singular: a válvula
• plural: as válvulas

The accent mark shows the stressed syllable: VÁL-vu-la.

Perdeu is the pretérito perfeito (simple past) of the verb perder.

Here it means lost:

• perder = to lose
• perdeu = he/she/it lost; you lost; formal you lost

In this sentence, the subject is a válvula, so perdeu means:

• the valve lost

In Portuguese, perder ar is a very natural way to say that something is losing air or has gone flat / leaked air.

So:

• A válvula perdeu ar. = The valve lost air.

Even if English would often say The valve leaked or The valve is leaking air, Portuguese commonly uses perder ar in this kind of context.

Because ar is being used in a general, uncountable sense: air.

So:

• perdeu ar = lost air

This is similar to English, where we usually say lost air, not lost the air.

If you add an article, the meaning can become more specific or less natural in this context.

A rough guide is:

• A = a very reduced sound, often like uh
• válvula = VAL-vu-luh
• perdeu = roughly per-DAY-oo in careful approximation
• ar = sounds like ahr, though in European Portuguese the final r is not like a strong English r

A very rough English-style approximation could be:

• uh VAL-vu-luh per-DAY-oo ahr

But European Portuguese has vowel reduction, so unstressed vowels are often weaker than an English speaker expects.

Yes. The subject is A válvula.

Portuguese often allows omitted subjects, but in this sentence the noun is explicitly present:

• A válvula = the subject
• perdeu = the verb
• ar = the object/complement

So the structure is straightforwardly:

• The valve
  • lost
    • air

Not literally, because válvula means valve, not tire/tyre.

However, in context, if someone is talking about a tyre problem, this sentence might imply that the valve was the part through which the air escaped.

If you want to say The tyre lost air, you would normally say:

• O pneu perdeu ar. in Brazilian Portuguese
• O pneu is also understood in European Portuguese, though o pneu / o pneu do carro depends on context

In Portugal, pneu is the usual word for tyre/tire.

Yes. Perdeu comes from perder, which has several meanings, including:

• to lose
• to miss
• to waste
• to forfeit

Examples:

• Perdeu a chave. = He/She lost the key.
• Perdeu o comboio. = He/She missed the train.
• Perdeu tempo. = He/She wasted time.

In A válvula perdeu ar, the meaning is clearly lost air.

Yes.

• perdeu ar = lost air / has lost air / a completed past event
• estava a perder ar = was losing air / ongoing in the past

So:

• A válvula perdeu ar. = The valve lost air.
• A válvula estava a perder ar. = The valve was losing air.

In European Portuguese, estar a + infinitive is the normal way to express an ongoing action.

Yes, it is natural and correct.

A válvula perdeu ar. is a simple, idiomatic sentence in European Portuguese, especially in mechanical or practical contexts. It sounds like something someone might say when describing a fault in a tyre, pump, or other air-containing system.

The plural would be:

• As válvulas perderam ar.

Breakdown:

• as = the (feminine plural)
• válvulas = valves
• perderam = lost
• ar = air

So it means:

• The valves lost air.

Yes. Since válvula is feminine singular, you could use ela:

• Ela perdeu ar. = It lost air.

However, Portuguese uses ele/ela for things more freely than English uses he/she for objects. In English we usually say it, but in Portuguese the grammatical gender of the noun determines the pronoun:

• a válvula → ela

In practice, though, keeping the noun is often clearer.