1. Brown
   Clear
2. Orange
   Red

An oil spot under your car will consist of brown fluid. Most of the time, it'll be because of wear-and-tear on gaskets, seals and connections — and don't forget to check oil pan seals, which are under the car.

1. Antifreeze
   Brake fluid
2. Power steering fluid
   Transmission fluid

Ethylene glycol antifreeze is that green or orange sweet-smelling fluid and could be the first symptom of a leak. If you don't notice the indicator lamp on your dashboard, you will notice when your car's engine overheats.

1. True
2. False

True! The thermostat's job is to block the flow of coolant to the radiator until the engine has warmed up. A broken thermostat won't let coolant reach a hot engine, thus causing it to overheat.

1. An air/fuel mixture
   Compression
2. Propulsion
   A spark

For your car's engine to start, it needs to have good air/fuel mixture, compression and a spark (that's the ignition).

1. You've broken your wrist pin.
   You've damaged your cylinder liners.
2. You've damaged your piston rings.
   The part that connects the piston to the crankshaft is broken.

"Throwing a rod" means a connecting rod, which connects a piston and the crankshaft, has broken. You're in for a major overhaul if this happens, and potentially a long walk.

1. An Intake manifold gasket leak
   A clogged fuel injector
2. A worn spark plug
   Any of these could do it.

If your car's engine is shaking so badly you can feel it in both your steering wheel and your seat, there's a misfire problem. This might mean a worn spark plug, an intake manifold gasket leak, a clogged fuel injector or another issue.

1. Loose fan belt
   Loose engine block
2. Loose cylinder heads
   Bad motor mounts

Excessive engine vibration, usually because of bad motor mounts that aren't holding it securely, can be felt on the passenger's side of the car.

1. Antifreeze (or water) contamination
   Gasoline contamination
2. Transmission fluid contamination
   Washer fluid contamination

Motor oil normally can be amber to dark brown to almost black depending on how used and dirty it is. If it's a foamy, milky white, however, it means that some antifreeze (or water) has contaminated it, and you'll want to look into what could be leaking from the car's cooling system.

1. The radiator is leaking.
   There's an oil or antifreeze leak.
2. The water pump is misaligned.
   A drive belt is damaged.

Sizzling indicates there's a fluid — engine oil or antifreeze — leaking onto something hot, like the exhaust manifold.

1. Carbon buildup
   Bad spark plugs
2. Low fuel octane
   Any of these could cause knocking

There are a few reasons, and degrees of severity, for your engine to start pinging or knocking at you. It happens because of a problem with the air-fuel mixture and could mean: You need to use a different fuel octane, there may be carbon buildup or the spark plugs need replacement. Left unfixed, it can do some serious engine damage.

1. You have damaged rod bearings.
   You have damaged wheel bearings.
2. You have a worn front axle.
   You have worn control arm bushings.

A deep, low-pitched knocking that's more like hammering than pinging is called a "rod knock." This happens from wear-and-tear or damage to the rod bearings — and it's a fatal engine problem if not repaired.

1. Bubbles in the radiator
   Complete engine failure
2. Engine sputter
   Loud clunking noises

Although all of these are signs that your car's engine has seized or is about to seize, the most common symptom is complete engine failure. A lack of lubricating oil is a common cause of this potentially expensive situation.

1. It's too cold outside.
   The engine is flooded.
2. The engine has seized up.
   There's a coolant loss.

Together, these symptoms usually indicate the car's engine is flooded. This means that there is too much fuel in the air/fuel mixture (often caused by pumping the accelerator too much) for the mixture to ignite and turn the engine.

1. Start the engine while holding the gas pedal to the floor.
   Pump the gas pedal while cranking the engine.
2. Check your oil.
   Buy a car without a carburetor.

A car can get flooded when the mixture of fuel and air gets off balance, most commonly in cars that have a carburetor instead of fuel injection. The best way to solve it is to let the excess fuel evaporate, so wait as long as you can, and then try to start the engine while holding the gas pedal to the floor — but don't pump it, because that could be what got you in this predicament to begin with.

1. Clogged fuel filter
   Dirty spark plugs
2. Damaged spark plug wires
   any of these

When your car feels sluggish and you can hear popping from under the hood, it could be anything from dirty or damaged spark plugs and spark plug wires to a clogged fuel filter or, possibly, exhaust problems or trouble with the car's catalytic converter.

1. Fuel line obstruction
   Damaged fuel injectors
2. Air filter problem
   It could be any of these reasons

Black smoke coming from a car's exhaust pipe can happen because the engine is flooded with gasoline, typically by fuel line issues or damaged fuel injectors and sensors. Black smoke can also mean a problem with your car's air filter.

1. A damaged head gasket
   An overheating engine
2. A cracked engine block
   It could be any of these problems

On a cold morning, you may notice white vapor coming from your exhaust pipe. It's normal and stops as soon as your car warms up — probably no longer than 20 minutes. But, if it's white smoke coming from your car's exhaust pipe, that can be caused by any of these problems — and could be serious.

1. Coolant
   Gasoline
2. Oil
   Transmission fluid

Blue smoke indicates there's a problem with leaking and burning oil. This could be caused by faulty engine seals leaking oil into the cylinders.

1. A bad oil pump
   A faulty oil pressure sending unit
2. A loose oil filter
   Worn engine bearings

First, check that your oil level isn't low. Not the problem? It could be oil pressure. If that's not about 10 PSI for every 1,000 RPMs of engine speed, it could be a bad oil pump; if that's not it, it could be that the oil pressure sending unit is on the fritz. But the worst-case scenario is worn engine bearings, which means your engine will soon need to be either rebuilt or replaced.

1. Engine won't start
   Moisture on the distributor cap
2. "Service Engine Soon" light
   Overheating

The most common three engine problems are: 1) the engine won't start, 2) "Service Engine Soon" light comes on and 3) overheating.

1. Defective cam lobes
   Defective valve train push rods
2. Defective valve train rocker arms
   Defective valve train valve lifters

Clicking noise, also called "chatter," is generated by your car's valve train when hydraulic valve lifters (also known as hydraulic tappets) become defective.

1. A bad crank position sensor
   A bad ignition coil
2. A broken timing belt (or chain)
   An engine vacuum leak

Poor gas mileage and stalling, as well as idling rough and, if you listen, a hissing sound from around the engine area under the hood, are symptoms of an engine vacuum leak.

1. A bad catalytic converter
   A dirty airflow sensor
2. A loose gas cap
   An oil change reminder

The ever-cryptic "Check Engine" light, also known as the "Malfunction Indicator" light, will trigger for a lot of things, including bad catalytic converter, for a dirty airflow sensor and a loose gas cap. What it won't do, however, is give you maintenance reminders.

1. The engine control module
   The engine control unit
2. The power control module
   These are all the same thing

The engine control module (ECM), also known as the engine control unit (ECU) or powertrain control module (PCM), handles the engine's performance by taking input from several different sensors and controlling the car's performance.

1. A loose hose is touching a hot part of the engine.
   The engine is overheating.
2. There is burned oil in the engine area.
   There is oil leaking onto the engine block.

A sweet, steamy smell inside your car is a coolant problem and means the engine is overheating. Better check it out.

1. Rust accumulation
   Lack of oil
2. A loose piston that's become lodged
   A damaged engine cylinder

Your car's engine may seize if there's a lack of oil, if there's rust accumulation or if there's a mechanical issue like a loose piston that's become lodged. A damaged cylinder will cause oil and coolant leakage and degraded engine performance.

1. Check for signs the engine's misfiring.
   Shut your car off, and restart it.
2. Tighten the car's gas cap.
   Ignore it.

While always on the vague side, a flashing "Check Engine" light is telling you the problem is more serious than a loose gas cap. Check for signs that your car's engine is misfiring, a serious problem that could cause damage to the catalytic converter.

1. Excessive antifreeze consumption
   Excessive oil consumption
2. Loss of power, both overall and during acceleration
   Overall poor driving performance

Excessive oil consumption, as well as poor performance and loss of power, are all common symptoms of worn piston rings.

1. Worn piston rings
   Piston slap
2. Low piston ring tension
   Cracked or burned piston

"Piston slap," the sound a piston makes when it rocks back and forth inside a cylinder (instead of traveling up and down as designed), sounds a lot like a bell. This can be caused by wear over time, and short of rebuilding the engine, there's not a lot to be done about it.

1. Low piston ring tension
   Worn piston pins
2. Worn piston rings
   Broken valve spring

Faulty piston pins cause engine knocking, but it's a really specific type: a metallic-sounding double knock, usually most noticeable at idle. This is usually because of a worn connecting rod and crankshaft bearings.

1. A change in fuel economy, for the worse
   Engine knocking
2. Stalling
   A sulfur smell in the passenger cabin

You'll know your car's MAF is bad because it can decrease your car's fuel economy by as much as 25 percent.

1. Performance problems
   Clogged fuel injectors, filters and lines
2. Fatal engine damage
   All the above

Diesel is thicker than gasoline, which means as soon as you started the car, the diesel went to work clogging your gasoline-powered engine's fuel injectors, filters and lines. If your car makes it home and continues to start, you'll feel timing and performance problems before the engine finally gives up. Your best bet is to have the fuel system flushed.

1. bad ignition coil
   high oil pressure
2. low oil pressure
   wrong octane gas

Dieseling, also called run-on, mostly happens when you fill up with the wrong octane gas for your car. A failing solenoid, carbon build-up or an overactive carburetor could also cause the problem.

1. Fuel
   Oil
2. Transmission fluid
   Water

If your engine is surging (also called "hunting") it's a sign that it's not getting the right fuel mix.