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I Have No Idea What's Wrong With My Car - Where Do I Begin?

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
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
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
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
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
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
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
Failing wheel bearing
Unevenly worn or misaligned tires
Screeching when car is
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
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
Low transmission fluid
Worn clutch or flywheel
Bad bearings
Failing differential
Normal operation in some vehicles
Whirring or buzzing in
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.

Emily Edwards

Emily is the Managing Editor at YourMechanic. Originally from Nova Scotia, she has a PhD from Trinity College Dublin and has been in California since 2015.