Glazed or slipping fan belt
Bad pulley driven accessory (alternator or water pump)
It won't be the engine that's squeaking, it will most likely be a belt, take it to a mechanic to get the belts tightened up.
Loose or worn belt.
Check for a worn or loose drive belt.
Most commonly caused by bad belts. It may go away as you rev the engine.
it could be anything, from the axles to an engine with a lack of oil.
I have a 2004 c230 and I had a squeaking noise when the engine first started. It was my water pump with uneven wear on the water pump pulley that was causing the sound. I will tell you it could be many different things, but this was my reason.
I hear a mouse squeaking. The door hinges are squeaking.
The positional sensor can produce squeaking in a car. The shocks can also cause squeaking in a suspension system of a car as well. Springs under the engine are known for this, too.
You'll most likely hear a knocking sound or squeaking of some kind
The cars makes squeaking sounds when your mother sits down on the seats!
check tension on fan belt(s)
belt