* Coolant Hoses: These are usually thick-walled, reinforced hoses carrying coolant (antifreeze/water mixture) to and from the radiator, engine block, heater core (inside the passenger compartment), and thermostat housing. You'll typically see at least two large coolant hoses running from the firewall area: one upper radiator hose and one lower radiator hose. There might be others, depending on the engine design and cooling system complexity.
* Vacuum Hoses: These are thin, often black rubber hoses, carrying vacuum pressure for various engine systems (brake booster, emissions control, etc.). They are typically numerous and smaller in diameter than coolant hoses.
* Fuel Lines: These hoses (or rigid metal lines) carry fuel from the fuel tank (often located in the rear) to the engine. Fuel lines are usually made of strong, fuel-resistant material and might be protected by shielding.
* Power Steering Lines: These carry hydraulic fluid to and from the power steering pump and rack. They are usually metal lines, but some vehicles might have sections of rubber hose.
* Brake Lines (sometimes): While brake lines primarily run beneath the vehicle, some components related to the brake system (such as a brake booster vacuum line) might have lines extending from the firewall.
Without knowing the specific make, model, and year of the vehicle, it's impossible to give a definitive list. The best way to identify them is to consult a repair manual specific to your vehicle. Many online resources, including diagrams, are available if you know your vehicle's details.
