Gaz vanası kapalı; bununla birlikte gaz sızıntısı devam ediyor.

Gaz vanası is a Turkish noun compound.

• gaz = gas
• vana = valve
• vanası = its valve / the valve of

In Turkish, compounds like X Y-si often mean the Y of X or the X Y in English.

So:

• gaz vanası = gas valve
• literally, something like the valve of gas

That -sı is the 3rd-person possessive ending, which commonly appears in this kind of compound.

You will see the same pattern in many everyday expressions:

• araba kapısı = car door
• ev anahtarı = house key
• su şişesi = water bottle

So gaz vanası is completely normal Turkish compound structure.

Kapalı is an adjective meaning closed or shut.

In Gaz vanası kapalı, Turkish is describing the state of the valve:

• gaz vanası = the gas valve
• kapalı = closed

So the sentence means:

• The gas valve is closed

It is not focusing on the action of closing. It is focusing on the result or condition.

Compare:

• Gaz vanası kapalı = The gas valve is closed.
• Gaz vanası kapanıyor = The gas valve is closing.
• Gaz vanası kapatıldı = The gas valve was closed / got closed.

So kapalı is the natural choice when you want to describe a current state.

In Turkish, the present-tense copula to be is often omitted in 3rd-person sentences.

So:

• Gaz vanası kapalı literally looks like Gas valve closed
• but it means The gas valve is closed

This is very common in Turkish:

• Kapı açık = The door is open
• Hava soğuk = The weather is cold
• Çocuk mutlu = The child is happy

If the tense changes, Turkish usually makes that explicit:

• Gaz vanası kapalıydı = The gas valve was closed
• Gaz vanası kapalı olacak = The gas valve will be closed

So the missing is is normal Turkish grammar.

Bununla birlikte is a connector meaning:

• however
• nevertheless
• even so
• sometimes with that said

Literally, it breaks down as:

• bu = this
• bununla = with this
• birlikte = together / along with

But in sentences like this, the whole phrase works as a discourse connector, not as a literal physical with this together.

So:

• Gaz vanası kapalı; bununla birlikte gaz sızıntısı devam ediyor.
• The gas valve is closed; however, the gas leak is continuing.

It is a bit more formal or written than a simple ama.

Yes, you could, but the tone changes a little.

Possible alternatives:

• ama = but
• ancak = however / but
• yine de = even so / still
• buna rağmen = despite this / nevertheless

Examples:

• Gaz vanası kapalı ama gaz sızıntısı devam ediyor.
  More conversational.

• Gaz vanası kapalı; ancak gaz sızıntısı devam ediyor.
  Neutral and common in writing.

• Gaz vanası kapalı. Buna rağmen gaz sızıntısı devam ediyor.
  Stronger sense of contrast: despite this.

• Gaz vanası kapalı; bununla birlikte gaz sızıntısı devam ediyor.
  Slightly more formal, polished, and written.

So the original sentence sounds natural, especially in formal or explanatory language.

Bununla comes from bu plus case endings.

The form is:

• bu = this
• bunun = of this
• bununla = with this

This is the instrumental/comitative meaning with.

Turkish often uses -la / -le to mean with:

• arabayla = with the car / by car
• arkadaşımla = with my friend
• bununla = with this

In this sentence, bununla birlikte is a fixed expression, so you do not need to analyze it every time. Still, knowing that bununla means with this helps you recognize the structure.

For the same reason as gaz vanası: this is another noun compound.

• gaz = gas
• sızıntı = leak, leakage
• sızıntısı = its leak / the leak of

So:

• gaz sızıntısı = gas leak / gas leakage

Again, Turkish commonly uses this compound structure where the second noun takes a possessive ending.

Compare:

• su borusu = water pipe
• trafik kazası = traffic accident
• telefon numarası = phone number

So gaz sızıntısı is the standard way to say gas leak.

Devam ediyor means is continuing or continues.

It is made of:

• devam = continuation / continuation state
• etmek = to do, to make

Together, devam etmek is a very common verb meaning:

• to continue

In the sentence, it appears as:

• devam ediyor = is continuing

This is the present continuous form of devam etmek.

You will see many Turkish verbs formed this way:

• yardım etmek = to help
• fark etmek = to notice
• kontrol etmek = to check
• devam etmek = to continue

So although it looks like two words, it functions as one verbal idea.

In Turkish, the -iyor form often covers both:

• is continuing
• continues / keeps continuing

So:

• gaz sızıntısı devam ediyor

can be understood as:

• the gas leak is continuing
• the gas leak continues
• the gas leak is still going on

The exact English translation depends on context. Turkish -iyor is broader than English is -ing in many situations.

Yes, the word order is completely normal.

Turkish often uses a simple topic + description structure:

• Gaz vanası = topic / subject
• kapalı = description

So:

• Gaz vanası kapalı = The gas valve is closed

You might also see:

• Gaz vanası kapalıdır

The ending -dır can add a more formal, factual, or assertive tone. It is often used in definitions, reports, or emphatic statements.

Compare:

• Gaz vanası kapalı. = The gas valve is closed.
• Gaz vanası kapalıdır. = The gas valve is closed. / The gas valve is indeed closed.

In everyday speech, the version without -dır is much more common.

The semicolon links two closely related clauses:

• Gaz vanası kapalı
• bununla birlikte gaz sızıntısı devam ediyor

It signals a pause stronger than a comma but weaker than a full stop.

In English, this is similar to:

• The gas valve is closed; however, the gas leak is continuing.

You could also write the Turkish sentence with a period:

• Gaz vanası kapalı. Bununla birlikte gaz sızıntısı devam ediyor.

That would also be correct. The semicolon just emphasizes the strong connection between the two ideas.

It mainly means closed.

For a valve, kapalı is very natural because a valve is something you open and close.

In English, depending on context, you might say:

• The gas valve is closed
• The gas supply is shut off

So the Turkish word is kapalı, but the best English translation may vary slightly depending on what sounds natural in context.

It is repeated for clarity.

The sentence says:

• Gaz vanası kapalı
• gaz sızıntısı devam ediyor

Repeating gaz makes the second noun phrase completely explicit: gas leak.

In some contexts, Turkish could omit repeated information if it is obvious, but here repetition is very natural and clear. It avoids any ambiguity about what kind of leak is being discussed.

So the repetition does not sound strange; it sounds precise.

Yes. A very natural alternative would be:

• Gaz vanası kapalı olmasına rağmen gaz sızıntısı devam ediyor.

This means:

• Although the gas valve is closed, the gas leak continues.
• Even though the gas valve is closed, the gas leak is continuing.

This version makes the contrast more explicitly subordinate, while the original sentence uses two separate clauses connected by bununla birlikte.

Both are correct, but the feel is a little different:

• ...; bununla birlikte ... = two separate statements linked with however
• ... olmasına rağmen ... = one sentence with although / even though

It sounds neutral to slightly formal.

Reasons:

• bununla birlikte is more formal than ama
• the wording is clear and report-like
• it would fit safety instructions, technical writing, or a careful explanation

In casual speech, many speakers would probably say:

• Gaz vanası kapalı ama gaz kaçağı devam ediyor.

That version is more conversational, and gaz kaçağı is another common way to say gas leak.

So the original sentence is natural, but it leans a bit toward formal written style.