Эвакуатор уже приехал.

It is in the nominative singular, because it is the subject of the sentence: the thing that arrived.

The dictionary form is эвакуатор, so this sentence uses the basic form of the noun.

A useful note: эвакуатор is a masculine inanimate noun.

Russian has no articles. So эвакуатор can mean:

• a tow truck
• the tow truck

Which one is meant depends on the context. In a real situation, this sentence often means the tow truck has already arrived, because both speakers already know which tow truck they are talking about.

Russian does not have a direct equivalent of the English present perfect form with has/have.

So where English says:

• The tow truck has arrived

Russian normally uses the past tense:

• Эвакуатор приехал

Adding уже gives the idea of already:

• Эвакуатор уже приехал = The tow truck has already arrived

So the Russian past tense often covers both English arrived and has arrived, depending on context.

Because приехать is used for arriving by transport / by vehicle.

• прийти / пришёл = come on foot
• приехать / приехал = come by vehicle
• прилететь / прилетел = come by plane
• приплыть / приплыл = come by swimming or by water

Since a tow truck is a vehicle, приехал is the natural verb.

Уже means already.

In this sentence, it modifies the whole idea of arrival:

• Эвакуатор уже приехал = The tow truck has already arrived

Its position is fairly flexible, but different word orders can change the emphasis a little:

• Эвакуатор уже приехал — neutral
• Уже приехал эвакуатор — stronger focus on already arrived
• Эвакуатор приехал уже — possible in speech, but less neutral

The most standard version here is Эвакуатор уже приехал.

In the Russian past tense, verbs usually include an -л- element.

Then the ending changes for gender and number:

• приехал — masculine singular
• приехала — feminine singular
• приехало — neuter singular
• приехали — plural

Since эвакуатор is a masculine singular noun, the verb is приехал.

Приехал is perfective.

That matters because perfective verbs usually show a completed action or a result. Here, the result is important: the tow truck has arrived and is now here.

Compare:

• приехал — arrived / has arrived
• ехал — was driving / was on the way
• приезжал — came by vehicle (at some time), often with no focus on the result being here now

So Эвакуатор уже приехал emphasizes that the arrival is complete.

Yes, if the context makes it obvious.

For example, if everyone is already talking about the tow truck, someone might simply say:

• Уже приехал. — It’s already here / It already arrived.

Russian often drops subjects when they are clear from context. But including эвакуатор makes the sentence clearer and more explicit.

Yes. Russian word order is more flexible than English word order.

These are all possible, but with different emphasis:

• Эвакуатор уже приехал. — neutral, most standard
• Уже эвакуатор приехал. — marked; may sound contrastive
• Уже приехал эвакуатор. — emphasizes the fact of arrival
• Приехал уже эвакуатор. — possible in conversation, with a more spoken feel

For a learner, Эвакуатор уже приехал is the safest and most natural version.

The stress is:

• эвакуАтор
• ужЕ
• приЕхал

So the full sentence is:

• ЭвакуАтор ужЕ приЕхал.

A rough English-style pronunciation guide would be:

• eh-va-koo-A-tər oo-ZHE pri-YE-hal

That is only approximate, but it helps you place the stress correctly.

They describe different stages of the situation:

• Эвакуатор уже едет = The tow truck is already on its way / already coming
• Эвакуатор уже приехал = The tow truck has already arrived

So:

• едет focuses on the movement in progress
• приехал focuses on the completed arrival

This is a very important distinction in Russian.