Noises, smells, leaks and operating changes are all signs that something could be wrong with your vehicle. To make maintaining and repairing it faster and easier, pay attention to these signals and be prepared to describe them to your automotive technician.

Here is a troubleshooting checklist (PDF) that will help you document problems with your vehicle. You can give this checklist to your counterperson, service advisor, or service technician when you take your vehicle in for service.


Performance Problems

Knowing something about how your vehicle performs and handles makes communicating with service advisers and technicians fast and easy.

Performance Problem How to Describe It
Cuts out Temporary, complete loss of power. Engine quits at sharp, irregular intervals. May occur repeatedly or intermittently. Usually worse under heavy acceleration.
Detonation Mild to severe ping, usually worse under acceleration and load. Engine makes sharp, metallic knocks that change with throttle opening. Sounds like marbles rattling around.
Dieseling Engine runs after ignition switch is turned off. Runs unevenly and may make knocking noises.
Hesitation Momentary lack of response as accelerator is pressed. Can occur at all speeds. Usually most severe when starting from a stop. May cause engine to stall.
Missing Pulsation or jerking that changes with engine speed. Exhaust has a steady spitting sound at idle or low speed. Not normally felt above 30 mph.
Rough idle Engine runs unevenly at idle. Car may also shake.
Sluggish Engine delivers limited power under load or at high speed. Won't accelerate as fast as normal. Loses too much speed going up hills. Has less speed than normal.
Spongy Less than anticipated response to increased throttle opening. Little or no increase in speed when accelerator is pushed down to increase cruising speed. Continuing to push pedal down will finally give an increase in speed.
Stall Engine stops running or dies out. May occur at idle or while driving.
Surge Vehicle speeds up and slows down with no change on accelerator pedal. Can occur at any speed.


What’s your car trying to tell you when it clicks, clunks and grinds? Translating these noise signals is key information for automotive technicians who are trained to identify problems via sound.

The important thing to remember with odd sounds is to be specific, narrow that ‘rattle’ down, and then detail when it happens — when the car’s hot, cold, at idle, moving at 90 kmph, etc.

Description Possible Problem
Squeaky brakes Dirt in the lining of the pads or hardening of the pads and shoes
Grinding brakes Worn pads and shoes
Metal on metal when braking Worn-out pads
Metal on metal when encountering bumps Worn-out shocks
Growling from air conditioner Worn compressor
Squealing windshield wipers Worn wiper blades
Whining from tires when turning a corner Dry or worn-out wheel bearings
Squealing from tires when turning a corner Tires low on air or worn
Grinding while shifting gears Worn clutch or clutch that need adjustment
Screeching under the hood Loose or worn belt
Popping from engine Dirty air filter, bad spark plugs, wires, ignition components
Scraping or buzzing from transmission Transmission needs new fluid
Squeaking noise when shifting Manual transmission needs lubrication
Clunking under hood when gears change Worn joints or engine’s idle speed may be set too high
Knocking under hood Need higher gas octane rating, clogged air filter or timing off
Clicking when idling Needs oil
Clunking that worsens as speed increases Broken or worn engine parts


Learning to pinpoint strange vehicle odors can help your automotive technician sniff out the real cause of the problem. Here are a few common odiferous car complaints.

Description Possible Problem
Sweet odour, usually accompanied by steam from under the hood Antifreeze or coolant leak
Clear liquid with a smell Brake fluid leak
Heavy, thick odour, possibly accompanied by smoke from
under the hood or from the exhaust
Burning oil
Acrid odour, like burned toast Electrical short
Continuous, heavy sulfur odour, like rotten eggs Emissions
Burning material or rubber odour Overheated brakes or clutch
Metallic odour, usually accompanied by antifreeze/coolant odour Overheating


If your vehicle is leaving strange stains or other visual signs behind on the driveway, you need to pinpoint the following signals:

Description Possible Problem
Black stains with a heavy, thick consistency Axle leaks
Clear liquid with a smell Brake fluid leak
Yellow, green, pink or orange-coloured stains
that are lighter and thinner than oil
Coolant leaks
Brownish-coloured stains Crankcase or power steering leaks
Clear liquid with no smell Just dripping water that has condensed on your air conditioner
Black fluid Motor oil leak
Greasy fluid that is pink, red or clear Power steering or transmission leak
Reddish-coloured splotches Transmission leaks