It happens all the time. You’re in the car and suddenly, “fwuup, fwuup, fwuup, fwuup”. What the heck? Is it serious? Should I stop, or can I get where I’m going, and worry about it later?
Internet diagnosis is no substitute for having a real, live mechanic look at your car, but I can give you a few quick ideas to let you make a more informed choice about stopping or driving on when you hear an unusual noise. It may also help you to sound like you know what you’re talking about when you DO call the mechanic. This can help prevent repair rip-offs.
Funny sound at the back of the car.
From the rear, you get sounds related to TIRES, BRAKES, EXHAUST, FUEL PUMP, and sometimes (if the car is rear-wheel drive) from the DIFFERENTIAL (that big lump where axles from both rear wheels meet). Rhythmic “fwuup-fwuup” sounds that happen while the car is moving are usually tire related. (Look for lumps or exposed chords, and replace the tire if you find them.) Rhythmic or continual squealing (“screeeeeeeach!”) sounds are often brakes. While you don’t want brakes to go unchecked for long, you don’t need to panic right away.
Some brake repair tips.
Look at your rear wheels. Can you see a flat silver disc when looking through the spokes of the wheel, or holes in the wheel cover? If so, you have DISC BRAKES. Squealing disc brakes are a sign that they’re wearing out. Manufacturers put a “wear bar” into your brake pads, and as they wear down, this bar contacts the disc, and squeals. It’s annoying, but not dangerous yet. If you see deep grooves on the disc, it MAY be dangerous. If the sound from the rear of the car is more of a “graaaawwwtch..”, that is likely metal-on-metal contact, and it means your brake pads (the part of the brake that squeezes the disc to slow you down) are GONE, or there is some foreign matter (like gravel, or a nail) wedged between the pad and disc. This is potentially dangerous, and should persuade you to find a brake shop quickly.
Adjusting drum brakes.
If you don’t have disc brakes, you have DRUM BRAKES. (Many cars have discs on front, and drums on the rear.) Sounds from drum brakes are similar to disc brakes, but they may allow you to do some easy adjusting to make the sound go away. Find an empty parking lot, and put the car in reverse. Back up at a decent speed, and apply the brakes firmly. Do this several times. Drum brakes are self-adjusting, and doing this will make the squealing go away until they really are worn out. It will also make your brakes “tighter”, so be careful. It’ll feel like you have new brakes!
Problems with the differential.
If your funny sound is coming from the DIFFERENTIAL, you probably aren’t going to get very far. There are precision gears in the differential, and if it’s grinding or squealing, something serious is wrong. If you can reach it, carefully put your hand close to it, but do not touch it. If you feel heat boiling off of it, the differential could be low on its special lubrication, or clearances could be off.
Fuel pump noise.
Most modern cars also have a FUEL PUMP located in the fuel tank at the rear of the car. Sometimes, these will exhibit a high to medium pitched squealing or whirring noise before going out. Some pumps make this noise all the time. You can extend the life of your fuel pump by keeping the gas tank at least ½ full all the time. This keeps the pump motor cooler. A dull “bzzzzzz”, or “click, click” as you turn the car on means the pump has probably kicked the bucket. Note that if you’ve been in a minor accident, your fuel pump may not work because it’s been automatically shut off to avoid a fire. Your owner’s manual can tell you where the FUEL PUMP RESET BUTTON is, and this will re-start the fuel pump.
Funny sounds at the front of the car.
There’s a lot more going on in the front of the car. Squeaking and grinding that happen while the car is moving, and change pitch with speed still point to brakes, so follow the guidelines above.
Continuous squeaks while the engine is running can be a number of things. Most commonly, it is a BELT that needs tightening or replacing. A squeaking belt may also indicate that a gasket or seal in the area is leaking, allowing lubrication to get on the belt. Looking under the hood while the engine is running can help you isolate the location of the noise. Belt noise is usually pretty obvious. Be careful when looking at a running engine. There are spinning, moving parts that can grab clothing and hands, causing serious injury. Do not wear scarves or loose gloves around an engine!
The car makes a high-pitch “fweeeeeeeeee!” sound when the engine’s running.
High-pitched noise while the engine is running can be a few things. A leaking, or disconnected VACUUM HOSE can make this noise, and cause the engine to run rough, or some accessories not to work. Vacuum hoses are small, flexible, and run all throughout the engine compartment. Driving with a vacuum leak will not normally harm a modern engine, because the computer adds any fuel the engine needs to make up for extra air that’s leaking in. Nonetheless, it’s a good idea to get it fixed soon.
SMALL MOTORS that operate various accessories also make this noise. This will be annoying, and possibly cause some accessory to stop working, but will usually not cause any lasting harm.
The car makes a mid-pitch “whirrrrrr” sound, which changes tones as you turn the steering wheel.
This is probably coming from the POWER STEERING PUMP, or the RACK AND PINION STEERING mechanism. Often, this noise can be fixed by adding power steering fluid to the appropriate container (consult your owner’s manual). These noises are annoying, but you can drive thousands of miles with no serious problems. If you notice seriously “notchy” steering, get it to a mechanic soon.
The engine makes a repetitive “clacking” sound.
A clacking noise that comes from the engine area, and speeds up with the speed of the engine (“clack…clack…clack..clack..clack,clack,clack,clack”) is a “kind-of-bad” to “major-bad” sign. Check and add oil if necessary. If this does not help, your engine needs attention. It could be cams, lifters, fuel injectors, or other things. It may get you where you’re going, but you’re doing some damage to it. Work will be needed soon.
There’s a “pffft…pffft…pffft!” sound that speeds up as the engine is revved.
Air is leaking from the EXHAUST SYSTEM at some point. In older cars, it was common for the gasket between the engine and exhaust manifold to develop small leaks. The high pressure air shooting out made a sharp sound so distinct that it could be mistaken for metal-on-metal contact. Newer cars sometimes develop leaks from pipe joints, or holes in the exhaust system which make this sound. If fumes from a leaking exhaust system are able to get into the passenger compartment, they can be very harmful. If you start having an unusual headache, or feeling drowsy or confused, you may be suffering from this type of poisoning. Do not drive under these conditions!
The car goes “clunk, clunk” when you speed up, slow down, or turn.
This sound will come from beneath the car, and varies in location, depending upon the car. Often, this is what’s called a “U-JOINT”. It’s a flexible joint that transfers power from the transmission to the drive wheel(s). They wear out, get too much clearance, make noise, and break. Depending on how you drive, and how heavy and/or powerful your car is, this may represent imminent failure, or a mere annoyance. Heavy, powerful vehicles break u-joints quickly. Small, light cars, with less powerful engines wear them out slowly, and can go a long time before they actually break. There is a slight chance this noise is not from a u-joint, but instead from a broken frame, or sloppy suspension bushing, which allows the body to shift and move as you apply power. This (sloppy bushing) also explains clunking noises that happen when you turn the steering wheel back and forth. Worn bushings in the steering system should be replaced soon, as they can make sudden maneuvers difficult and unpredictable, and often cause the car to veer to one side during heavy breaking.
There is a loud metallic “bzzzzzzzzzz!” when you turn the engine on.
This is often some physical interference with a moving part. It might be relatively harmless, like a leaf or twig against a fan blade, or it might be bordering on catastrophic, like when something inside the engine has broken, and is rubbing against something else. If you can’t verify quickly that this is a leaf in your vent system (try turning up the fan all the way to blow it out), shut the engine off, and seek help.
My car won’t start; it goes “click, click” when I turn the key.
This can be a failed starter motor, or a battery with insufficient power to turn the engine over. If a jump-start fixes it, it’s most likely the battery. Sometimes this problem is caused by a faulty GROUND WIRE, often a wide, braided metal wire bolted to the engine and the body of the car. Reattaching this wire will have an almost magical effect. Sometimes, the battery cables are not fastened firmly to the battery, and tightening them will help.
There is a periodic “Snap! Snap!” from under the hood while the engine is running.
This is the sound of a faulty spark plug wire. Electricity that is supposed to be going to your spark plugs is leaping to some other location, making a “Snap, snap!” sound as it arcs. If you’re near it, you may experience a painful shock. The wire may have come off the plug, or the wire may be simply worn out, and electricity is able to come through it’s protective coating and connect to nearby metal. No harm should come to the engine by driving it under this condition, but you will have less power than normal, and poor fuel mileage.
There is a “gzzzzzzt!” sound, when I turn the key.
This is some electrical component grounding out where it should not. It is potentially dangerous, and can cause a fire. If you smell smoke, or a funny, pungent aroma (the smell of melting plastic that covers electrical wires) turn the key off, and get out immediately! The upholstery and plastic in modern cars is very flammable, and can erupt in flames with amazing speed. The fumes from this burning material are also fatal. (You do carry a fire extinguisher, don’t you?) If the car catches fire in your garage, it’s liable to take out the entire building.
The engine went “TWANK!“, and died.
Yes, your engine is dead. Call the mortician, and stick a fork in it; it’s done. Especially if you suddenly notice a quantity of oil beneath the car. The slightly modified version of this is “tappa-tappa-tappa-clunk, clunk, clunk, TWANK!” This is the sound of a rod beginning to fail, then letting a piston slam into the cylinder head, and cause catastrophic failure. You will likely need a new engine. Sorry. At least if it gives you this warning, you might be able to push in the clutch pedal before it gets to “TWANK!” This can save you from sudden deceleration, which could be dangerous.
The previous descriptions are not all-inclusive, and my interpretation of sounds may differ from your own. Good luck in your diagnosis and repairs, and may your engine never go “TWANK!”
