If you’re like the majority of people in the U.S., you use a car to get from Point A to Point B and rely on all the parts working properly. None of us expects to break down on the side of the road, and when it happens it’s extremely inconvenient and stressful. Worse still, we rarely see it coming.
We assume our car is going to work - until it doesn’t. Either there weren’t any warning signs or you didn’t see them. Or maybe there were signs and you didn’t even know. OK, maybe you even neglected some things you now recognize as “signs!”
Most of the time, you don’t need to know anything about what goes on underneath the hood, but when something goes wrong you start to wish you knew a little bit more about the mechanics of it all. There’s an odd clunking noise coming when you drive over a bump but, other than that, you can’t really say what’s going on with your usually trusty car.
Here at YourMechanic, we know that very few car owners are expert diagnosticians and oftentimes you don’t even know which service you need to book.
This is a very common situation and it’s why we have hundreds of diagnostic jobs - our mechanics are great at figuring out what’s going on with your car. You don’t even have to pick a specific job when you book an appointment if you can’t identify any symptoms at all, but the more information you are able to share before the mechanic comes on-site, the better.
When trying to decide which service to book, consider what you see, smell, hear, and feel. Once you’ve identified the sense your issue applies to, focus on the qualities of each sensation. For example, if there’s an odd feeling to your car, think about if it’s vibrating or if it’s pulling to one side.
Here are some guides you can use to help you decide which service to book if you smell something unusual in your car:
| Using Your Sense of Smell to Diagnose Issues With Your Car | |
|---|---|
| Smells Like | What It Could Mean |
| Burning wood or rubber | Overheating brakes or tires (rubber smell) Malfunctioning clutch (wood smell) |
| Exhaust | Carbon Monoxide (CO) may be leaking into the car (note that CO is colorless and odorless but is part of exhaust gas) |
| Gasoline | Leaking fuel system component Failing evaporative emissions system component |
| Hot or burning oil (often referred to as "exhaust smell") |
Engine oil leaking, possible from a failed gasket or seal |
| Mildew or mold | Cabin air filter needs replacement Buildup on evaporator Water inside the car |
| Sulphur | Failing catalytic converter Overcharged battery Issue with fuel system |
| Sweet | Leaking coolant |
Here are some guides you can use to help you decide which service to book if you feel something unusual in your car:
| Using Your Sense of Touch to Diagnose Issues With Your Car | |
|---|---|
| Feels Like | What It Could Mean |
| Air is not coming out of vents | Blown fuse Bad relay Damaged blower motor Malfunctioning blower resistor Clogged air intake Broken hose |
| Brake pedal is hard to push | Bad brake booster Vacuum hose is leaking Brake booster check valve malfunction Failing or incorrect brake component Clogged proportioning valve |
| Brake pedal is lower than usual | Air in the hydraulic system Leaking brake lines Leak in master cylinder Rear brakes need adjusting Warped brake rotors |
| Brakes need to be pumped | Air in brake lines Low brake fluid Failing master cylinder Moisture in brake fluid Damaged/missing bleeder valve Warped brake rotors |
| Brake pedal vibrates or shakes | Warped brake rotors Failing wheel bearings Loose lug nuts Wheels out of alignment |
| Car has bouncy and unstable ride | Damaged struts, broken strut assembly, or shock absorbers Poorly lubricated suspension Incorrect tire inflation Bulging or worn tires |
| Car has excessive body roll | Loose or worn suspension Shocks need replacing Worn tires Damaged stabilizer bar or stabilizer bar link Modifications to the vehicle |
| Car is hard to shift | Leaking transmission fluid Failing transmission solenoids Contaminated transmission fluid Failing transmission Bad shifter cable Worn clutch |
| Car is hesitating and bucking | Misfiring cylinder(s) Clogged fuel filter Failing fuel pump Failed oxygen sensor Clogged EGR valve Worn spark plugs and wires |
| Car jerks forward at high speeds | Failing mass airflow sensor Leaking engine vacuum line Malfunctioning fuel pump Misfiring cylinder(s) |
| Car is leaning to one side | Struts or shock absorbers are stuck Broken or bent suspension component Twisted chassis Differently sized tires |
| Car pulls to left or right while braking |
Uneven tire pressure Brake system problems Worn suspension components |
| Car pulls in one direction while driving |
Uneven tire pressure Wheels out of alignment Brake system problems Bad wheel bearing Worn suspension components Worn steering linkage Torque steer (this can be normal on some front-wheel drive cars) |
| Car is shaking or vibrating | Problems with tires Engine misfiring Warped brake rotors Worn engine mounts Suspension problems |
| Car or steering wheel shakes when braking |
Warped or uneven rotors Rotor run-out |
| Car shudders when turning | Low power steering fluid Failing power steering pump Kinked or blocked power steering line Failing wheel bearing Failing differential |
| Car vibrates going uphill | Damaged CV axles or joints Failing U-joint Low/contaminated differential fluid Engine misfiring |
| Clutch pedal inoperative | Broken clutch cable Missing connector rod Low clutch fluid Failed clutch master cylinder Failed slave cylinder |
| Engine is shaking, pulsating, or vibrating |
Worn spark plugs and wires Loose or disconnected engine hoses Loose battery terminal connections Dirty or clogged air filters Loose timing belts |
| Excessive car bounce and sway | Wheels need alignment Excessive/uneven wear on tires Loose steering linkage Damaged or weak struts or shocks Damaged suspension component |
| Seat shakes or vibrates | Seat is not fully secured to vehicle Worn out suspension parts Warped brake discs Failing brake drums Imbalanced wheels |
| Steering wheel feels loose | Worn tie rods Worn pitman or idler arm Worn ball joint Loose suspension component |
| Steering wheel is hard to turn | Low power steering fluid Weak or damaged power steering pump Damaged power steering belt Damaged steering rack Low tire pressure |
| Steering wheel vibrates or shakes | Imbalanced wheels Loose lug nuts Failing wheel bearings Worn tires Warped brake rotors |
Here are some guides you can use to help you decide which service to book if you hear something unusual in your car:
| Using Your Sense of Hearing to Diagnose Issues With Your Car | |
|---|---|
| Sounds Like | What It Could Mean |
| Backfires | Moisture in the fuel system Unbalanced air-to-fuel ratio Leaking vacuum hoses Malfunctioning air intake valve Incorrect ignition or valve timing |
| Banging | Bad sway bar link Worn control arm bushings Worn ball joint or other suspension component Loose brake caliper |
| Clunking when going over bumps |
Failing control arm bushings Failing stabilizer end link Failing ball joint or suspension component Worn or loose steering system component Exhaust system issue |
| Clicking or popping | Damaged CV joint Bad struts Loose hubcaps Loose drive belt or tensioner Worn tires Low engine oil Dead battery |
| Clicking when turning car | Torn CV boot Worn or dry CV joint Damaged driveshaft or differential Worn tires Worn wheel bearings |
| Creaking or squealing when turning car |
Low power steering fluid Loose or worn power steering belt Worn shocks or struts Dry or damaged suspension bushings Worn ball joints Damaged tie rod ends Damaged power steering components |
| Grinding when braking | Excessive brake pad wear Foreign debris lodged in brakes Low quality brake pads Wear indicator contacting rotor Rusted brake rotors |
| Grinding while shifting (manual transmission) |
Forgetting to engage clutch Worn clutch Worn gear synchronizers Cracked or chipped gear teeth Low or contaminated transmission fluid |
| Grinding in transmission (automatic) |
Low or contaminated transmission fluid Low differential fluid Cracked or chipped gear teeth Failed valve body Failed friction component |
| Grinding when turning key in ignition |
Bad starter drive gear Bad starter solenoid Failing clutch, flywheel, or pressure plate |
| Gurgling or bubbling | Improper coolant service Blown head gasket Air in the heater core or cooling system Low coolant Overheating engine Normal operation of some coolant systems |
| High-pitched squealing when applying brakes |
Worn brake pads Glazed or oxidized brake discs Problem with the brake master cylinder or caliper Damaged brake backing plate |
| Hissing | Worn hoses Leaking coolant Overheating engine |
| Hissing when applying brakes |
Leaking vacuum line Leaking brake booster diaphragm Damaged or missing foam silencer Failing master cylinder |
| Humming | Worn or unevenly wearing tires Failing wheel bearings |
| Irregular clunking or knocking |
Failing ball joints Bad stabilizer ball link Worn or loose tie rods Worn or failing suspension components |
| Knocking when going over bumps |
Bad struts or strut mounts Bad ball joint Worn or failing suspension components |
| Loud noise from rear brakes |
Worn brake pads Broken or missing caliper bolt Contact with pad wear indicator Parking brake shoes stuck Wheel bearing failure Pads settling into place or normal pad vibration |
| Loud noise when putting car in gear |
Low transmission fluid Failed motor mount Failing U-joint or CV joint Worn clutch Failing bearings Failing internal transmission component |
| Loud noise when using the clutch |
Worn bearings (throw out, pilot, release, input) Worn clutch Failed flywheel |
| Low rumble or whir | Loose or broken heat shield or dust shield Unevenly worn tires Failing wheel bearing |
| Metallic tapping, knocking, or slapping |
Low motor oil Improper timing Incorrect air-to-fuel ratio Improper fuel octane level Overheating engine Engine calibration issue Loose or broken heat shield |
| Noisy power windows | Failing power window motor Failing regulator Dry or dirty window tracks |
| Repetitive screeching | Worn serpentine belt Weak belt tension or failing belt tensioner Seized engine pulley |
| Rotational noise that increases with vehicle speed |
Failing wheel bearing Unevenly worn or misaligned tires |
| Screeching when car is started |
Worn drive or auxiliary belts Worn pulleys or tensioners Wrong tension, alignment, or belt size Failing starter Failing engine accessory Failing engine component |
| Sputtering | Engine misfiring Blocked or malfunctioning fuel injector Clogged catalytic converter or exhaust system component |
| Squealing or rattling in engine |
Stretched belt Failing pulley bearings Loose exhaust component Loose or broken heat shield |
| Squealing or squeaking from timing belt |
Failing water pump pulley Serpentine or V-belt slipping Pulley misalignment Dry or cracked belt Belt is too tight |
| Sudden, loud exhaust note | Broken muffler or exhaust pipe Cracked exhaust manifold Broken catalytic converter |
| Whining sound while in gear |
Low transmission fluid Worn clutch or flywheel Bad bearings Failing differential Normal operation in some vehicles |
| Whirring or buzzing in engine |
Worn engine bearings Failing water pump Failing engine accessory Failing belt tensioner Accessory belt issues |
If something is leaking, a light is on, there’s a funny smell, or a part is simply not working and you have no idea why, we have a job for that. Check out the Diagnostics section of our service page to find out more about that mysterious popping sound coming from your wheels, and book a mechanic to come inspect your car today. After the mechanic finds out what’s causing the problem, repairs will be recommended - if needed - to get your car back in top shape, and with your approval, fix them conveniently at your location.
