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Water leaking from the exhaust pipe of a car is caused by the catalytic converter and the condensation of water vapor, according to autoupkeep.com. This is normal and nothing to worry about.

Combustion

The combustion of gasoline produces carbon dioxide and water vapor, according to chemistryland.com. Oxygen reacts with hydrogen in gasoline to produce water vapor, which exits the engine through the exhaust manifold.

Exhaust System

The exhaust, which includes carbon monoxide, nitrous carbon dioxide, water vapor and unburned gasoline are processed by the catalytic converter, which changes the gasoline to more carbon dioxide and water and directs them into the muffler.

Other Facts

In hot weather, the water vapor is less likely to condense and drain, but in cold weather, water vapor will do exactly that and drip from the tailpipe. Over time, water in the exhaust system can cause corrosion.

Complex machinery, like a cars transmission, requires periodic maintenance to ensure a long lifespan. Allowing air pressure into the transmission assembly can harm the transmission, rather than help.

Function

A typical transmission moves power from the cars engine, through its gear assemblies and out to the wheels to propel the vehicle forward. Transmission fluid flows throughout the assembly to provide pressurized cooling, lubrication and control gear shifting.

Considerations

Air pressure seeping into the transmission, such as from a leak, causes the transmission fluid within the hydraulic system to lose pressure. As a result, the clutch disc begins to slip, causing the vehicle to change gears roughly or not at all.

Prevention/Solution

To prevent air pressure from infiltrating the transmission, make sure all seals for the transmission filter and pan are free from cracks or twists. Verify that all bolts holding the filter and pan are torqued evenly so the seals can meet effectively.

The rocker arm of an internal combustion engine changes radial movement into linear movement; this kind of device is properly called a reciprocating lever. It takes the spinning motion of the overhead camshaft and turns it into the up-and-down movement that opens and closes the valves. Because they are typically made of steel, rocker arms have a great deal of strength for their weight, and can theore exert a great deal of leverage.

Cam Lobe

The camshaft is not a true spherical rod; it has bulges on it called lobes. The lobes project outward from one side of the shaft, while the back of the shaft -- opposite the lobe -- does not have a projection. As the shaft rotates, the side with the lobe lifts the outside end of the rocker arm, and then the side without the projection allows it to fall back. The cams movement is transferred to the rocker arm by a device called a cam follower, of which there are different types that vary by manufacturer and by vehicle age. As the cam shaft spins, the part of the rocker arm acted upon by the cam follower is lifted and lowered, lifted and lowered.

Valve

Just as the outside end -- the cam end -- of the rocker arm moves up and down, so does its opposite side. As the cam lobe comes round it lifts the outside of the rocker arm, which rocks, and the inner end pushes down on the valve stem, opening it against its spring. As the lobe rotates away from the rocker arm the outside drops, the inner end lifts and the valves spring closes it. In this way, the opening and closing of the valve is kept in sync with the rotation of the cam shaft, and thus with the movement of the pistons. Collectively, the cam lobe, follower, rocker arm, valve and valve spring are known as the valve train.

Ratio

Rocker arms have ratios -- the ratio is a measure of the arms leverage, which in turn determines how powerful the force is that it can transfer to the valve stem. The ratio is determined by the length of the arm, both between its center of rotation and the point it contacts the cam lobe, and between its center of rotation and the top of the valve stem. A typical automotive rocker arm has a 1:1.5 ratio, meaning that it moves the valve one and a half times further than the peak of the cam lobe projects up from the camshaft.

Problems

A tapping noise from the top end of the engine can indicate that insufficient lubrication oil is being delivered to the rocker arm. Most of the oil delivered to the top end of the engine is there to keep the camshaft area lubricated; much less is used for the rocker arms. Top end tapping is typically an early warning that an issue is developing with either the mechanical parts or with the lubrication system; prompt service is strongly recommended.

The automatic transmission has a storied past starting in the 1930s, when most automakers began rushing to develop a working automatic transmission. The first automatic transmissions were only partially automatic, as the driver had to select low or high range, but the transmission automatically shifted between the two gears in each range. In 1939, Oldsmobile released the first fully automatic transmission, the Hydra-Matic. Just as with the engine on a vehicle, the transmission needs cooling, which the vehicles cooling system performs.

Creation of Heat

As with all mechanical components on your vehicle, the automatic transmission creates heat as it works. This heat requires regulation, as excessive heat can cause component failure, resulting in breakdown.

Regulation of Heat

The cooling system, which includes the radiator, thermostat, coolant, water pump and radiator hoses, helps regulate the automatic transmission. The transmission does not have coolant running through it; rather the transmission fluid runs through the radiator to cool it off prior to running back to the transmission.

The cooling system, which includes the radiator, thermostat, coolant, water pump and radiator hoses, helps regulate the automatic transmission. The transmission does not have coolant running through it; rather the transmission fluid runs through the radiator to cool it off prior to running back to the transmission.

The manifold absolute pressure, or MAP, sensor plays a vital role in keeping an engine operating at peak efficiency. Without a properly functioning MAP sensor, an automobile engine will run poorly or may fail to run at all.

Purpose

The MAP sensor measures air pressure inside an automobiles intake manifold. The level of air pressure depends on how hard the engine is working. Under heavier loads, the engine uses more air, which reduces the pressure in the manifold. The engines computer uses the amount of pressure measured by the sensor to adjust the fuel injection and ignition timing.

Signs of Problems

A defective MAP sensor results in poor engine performance. Typical symptoms of MAP sensor failure include rough idle, stalling, spark plug "knocking" and an increase in fuel consumption. Auto-parts stores sell diagnostic scan tools, which determine if a MAP sensors working properly.

Replacement

A defective MAP sensor requires replacement. Manufacturers calibrate MAP sensors for specific models and engines, so car owners should note the type needed before purchase. When replacing the MAP sensor, drivers should also inspect the vacuum hose attached to it, and replace a hose showing cracks or other damage.

Like most other motorized or powerful electric devices on your car, the starter doesnt draw its power directly from the switch used to trigger it. Instead, the ignition switch triggers a sort of secondary switch, known as a relay or -- in the case of a starter -- the solenoid.

Starting System Basics

When you turn the ignition key on your car, the key closes a gap between the positive wire on your battery and a positive terminal on the starter solenoid, When the circuit closes on the solenoid, a switch inside of the solenoid closes and closes another circuit that links the battery and the electric motor on your starter. Hypothetically, you could just run a wire directly from the battery to the ignition switch and then to the motor, but that would require a lot of very heavy-gauge wire and a heavy-duty switch.

How a Solenoid Works

When electrical current from the switch enters the solenoid, it energizes a small electromagnet inside the solenoid. This electromagnet pulls on an metal arm attached to the batterys positive terminal against a metal plate attached to the starter terminal. In this way, the starter solenoid mimics the behavior of the ignition switch; you can think of the starter solenoid as a second ignition switch that sits in line between the battery and the starter.

Divorced vs Integrated

Modern starters generally use a starter solenoid integrated into the body of the starter itself, while older cars typically use a divorced solenoid mounted on the wheel well or firewall. The integrated solenoid and starter package is cheaper to produce and install because it reduced the number of connections in the electrical system and the machine processes necessary to install a separate solenoid mechanism in the engine bay. To locate your starter solenoid -- be it divorced or integrated -- simply follow the thick, red cable connected to your positive battery terminal.

Failure and Troubleshooting

A clicking starter solenoid usually indicates low battery power. The main starter circuit closing draws a great deal of power from the battery, which temporarily deprives the ignition switch of the amperage that it needs to trigger the solenoid. When the main circuit opens, power returns to the electromagnet, the circuit closes with a sharp click and the cycle starts over again. In this scenario, divorced solenoids have a slight advantage over integrated solenoids, since a driver can simply jump the exposed battery and starter terminals on the solenoid with a screwdriver. This circumvents the whole on-off-on cycle, possibly allowing a driver to start the car when he might otherwise end up stranded. This may be technically possible with some integrated solenoids, but the integrated solenoid is by nature harder to get to.