Motoren eksploderte.

Because motoren is the definite singular form: the engine.

In Norwegian, the definite article is usually attached to the end of the noun instead of being a separate word before it.

• en motor = an engine
• motoren = the engine

So the -en ending here works like English the.

Motor is a masculine noun in Bokmål.

Its basic forms are:

• en motor = an engine
• motoren = the engine
• motorer = engines
• motorene = the engines

A lot of Norwegian nouns use this pattern, so this is a very useful model to remember.

Eksploderte is the simple past (also called the preterite).

The verb is å eksplodere = to explode.

Common forms are:

• å eksplodere = to explode
• eksploderer = explodes / is exploding
• eksploderte = exploded
• har eksplodert = has exploded

So Motoren eksploderte is a past-time statement.

Because eksplodere is a weak verb, and in the past tense it takes the ending -te.

This is a common pattern for many Norwegian verbs, especially many verbs ending in -ere.

For example:

• å studere → studerte
• å reparere → reparerte
• å eksplodere → eksploderte

So the -te ending is a clue that the action happened in the past.

Yes, in this sentence it is.

• Motoren = subject
• eksploderte = verb

So the order is:

Subject + Verb

That looks very natural to an English speaker.

However, Norwegian main clauses follow the verb-second rule. That means if something else comes first, the verb still stays in second position:

• Motoren eksploderte.
• I går eksploderte motoren. = Yesterday, the engine exploded.

Notice that after I går, the verb eksploderte comes before motoren.

Normally, no.

A singular count noun in Norwegian usually needs either:

• an indefinite article: En motor eksploderte. = An engine exploded.
• a definite ending: Motoren eksploderte. = The engine exploded.

So Motor eksploderte sounds incomplete in ordinary Norwegian.

Yes, very closely.

It can be used intransitively, just like in this sentence:

• Motoren eksploderte.

That means the subject itself is what exploded.

You can also use related expressions in similar ways to English, for example:

• Bomben eksploderte. = The bomb exploded.
• Situasjonen eksploderte. = The situation exploded / blew up.

So for an English speaker, this verb is fairly straightforward.

It can mean either, depending on context.

In many sentences, motor is best translated as engine, especially when talking about vehicles or machinery:

• bilmotor = car engine

But in some contexts it can also correspond to English motor, especially for electric motors.

So in Motoren eksploderte, the best English translation is often The engine exploded, but the exact choice depends on what kind of machine you are talking about.

Yes. You would change the verb form:

• Motoren eksploderer. = The engine explodes / is exploding.

Compare:

• Motoren eksploderte. = past
• Motoren eksploderer. = present

So the noun stays the same, and only the verb changes to show time.

The infinitive is å eksplodere.

In Norwegian, infinitives are often learned with å, which works a bit like English to:

• å eksplodere = to explode

But in a normal finite sentence like Motoren eksploderte, you do not use å, because the verb is already conjugated.

So:

• dictionary form: å eksplodere
• sentence form: eksploderte