How an internal combustion engine functions:

Internal combustion engines operate based on the Otto Cycle, a theory developed by Nikolaus Otto in 1867. This cycle consists of four repeating stages, or “strokes”:

1. Intake  

2. Compression  

3. Combustion (or Power)  

4. Exhaust

During the intake stroke, the piston moves downward, drawing fuel and air into the cylinder through the open intake valve. As the Automotive Lift Repair Orlando piston moves upward with both the intake and exhaust valves closed, it compresses the fuel-air mixture. A spark plug then ignites the mixture, causing combustion. The resulting high pressure forces the piston downward. Afterward, the exhaust valve opens, and the piston moves upward again to expel the exhaust gases. This process then starts over.

Combustion involves converting chemical energy (from gasoline) into heat energy (from the combustion process), which is then transformed into reciprocating energy (piston movement). This reciprocating energy turns the crankshaft via a connecting rod. The crankshaft converts this reciprocating motion into rotational energy, which is ultimately transmitted to the wheels through the drivetrain, as discussed later in Lesson 9.

In diesel engines, there are no spark plugs. Instead, combustion is achieved through high compression alone, which generates enough heat to ignite the fuel.

The internal combustion engine helps generate electricity to recharge the battery, which also receives a charge during braking.

Engine Oil

Automotive Lift Repair Orlando Engine oil serves the crucial function of creating a lubricating film between the moving parts of an internal combustion engine to minimize friction and wear. Selecting the appropriate engine oil and changing it at the recommended intervals will help ensure your engine runs smoothly over time. You can find the recommended oil type and specification in your vehicle’s owner’s manual or on the oil fill cap. The choice will depend on the ambient temperature in your region. Your owner’s manual will specify two engine oil codes: an API and an SAE code.

The SAE (Society of Automotive Engineers) code denotes the oil’s viscosity or thickness. Modern oils are multi-viscosity. For example, an SAE rating of 5W-30 means the first part (5W) describes the oil’s viscosity when cold, while the second part (30) indicates its viscosity at the engine’s operating temperature. Older single-viscosity oils, like SAE 30, were very thick in cold weather, akin to pouring honey, making them difficult to pump and lubricate the engine. This is why older engines needed to be warmed up before driving.

Cooling System Overview

This Automotive Lift Repair Orlando lesson covers the engine’s cooling system, which is essential for dissipating the excess heat generated during the internal combustion process. The system uses coolant and a radiator to manage this heat. Coolant circulates through the engine’s channels, absorbing excess heat, and then moves to the radiator where the heat is released.

Regular maintenance of the cooling system is crucial to prevent overheating and avoid electrolysis, which can cause metal breakdown within the engine block. Maintenance schedules vary by vehicle make and model, and sometimes maintenance is needed before the mileage specified in the owner’s manual. For instance, if the manual recommends a coolant flush at 150,000 miles, it may be necessary to perform the flush earlier. Low coolant levels may indicate a leak, which can occur at various points such as the water pump, heater core, hoses, radiator, or other engine locations.

Automotive Lift Repair Orlando Coolant should be checked at each oil change (approximately every 5,000 miles). If the coolant is found to be dirty, a cooling system flush is required. Coolant contamination often results from mixing non-distilled water, which introduces impurities and causes corrosion that can clog the radiator and cooling passages. To prevent this, coolant should be mixed with distilled water, which lacks these impurities.

When checking coolant at home, always avoid opening the radiator cap while the engine is hot (refer to Lesson 2 for checking fluids).

Steps to Flush the Cooling System:

1. Consult the Owner’s Manual: Locate all cooling system components as described in the manual.

2. Drain the System: Open the radiator drain to release coolant into a container for recycling at an auto parts store.

3. Remove the Thermostat: Typically located on the engine side of the upper radiator hose, but sometimes on the lower hose.

4. Flush the System: Disconnect the lower radiator hose. Use a garden hose to force water through the thermostat housing and engine block until the water runs clear. Also, flush water through the radiator until it runs clear.

5. Drain Completely: Ensure all water is drained from the cooling system.

6. Reinstall Parts: Put the thermostat back in place.

7. Flush the Reservoir: Disconnect the reservoir, flush with a garden hose until clear, and drain completely.

8. Reconnect and Refill: Attach the hoses, close the drains, and fill the system with new coolant and distilled water, using a 50/50 mixture or pre-mixed coolant.

Note that flushing the Automotive Lift Repair Orlando cooling system will not address overheating issues. If your vehicle is overheating, as indicated by the temperature gauge, it requires diagnostic and repair.

After reassembling the Automotive Lift Repair Orlando cooling system, perform a pressure test to check for leaks. Rent a pressure tester from an auto parts store, follow the included instructions, and attach it to the radiator where the cap goes. Pump the tester until the gauge reaches the pressure indicated on the radiator cap, usually between 13-16 psi for modern vehicles. Let it sit for 20-30 minutes, then inspect the system for leaks and check for any pressure drop. A decrease in pressure suggests a leak.

Fuel System Overview

Before 1985, most Automotive Lift Repair Orlando ehicles used carburetors. A carburetor operates using a venturi—a narrowed passage within the carburetor—that draws fuel from a float bowl based on the volume of air flowing through it. While effective in its time, the carburetor is a less efficient method of mixing air and fuel compared to modern systems. This is why contemporary vehicles predominantly use fuel injection.

Remember to be aware of your surroundings when working near moving parts. One small oversight can lead to serious physical injury or even death.