Common problems
Engine problems: warning signs and what to do
The engine problems that matter most for safety are stalling and sudden loss of power while driving. Others, like burning oil, overheating and knocking, are warnings that serious and expensive damage may follow. A flashing check engine light means stop driving soon. Here is what each sign means and what to do.
Stalling and loss of power: the safety risk
If the engine stalls or loses power while you are moving, you can be left slowing down in traffic, on a highway or in the middle of a turn. When the engine stops, you may also lose power steering and brake assist. The steering wheel and brake pedal still work, but they feel much heavier and need far more effort.
Stalling and loss of power are among the engine problems that most often lead owners to complain to NHTSA, and some have led to recalls.
Warning signs and what they can mean
| Sign | Common causes | How urgent |
|---|---|---|
| Stalling or cutting out | Fuel delivery, sensors, electrical or software faults | High. Get it checked before relying on the car. |
| Sudden loss of power or "reduced power" mode | The engine computer protecting itself after detecting a fault, turbo or fuel problems | High. Get to a safe place and get it diagnosed. |
| Flashing check engine light | Severe misfire that can damage the catalytic converter | High. Reduce speed and stop driving as soon as you safely can. |
| Steady check engine light | Anything from a loose gas cap to a failing sensor | Medium. Have the codes read soon. |
| Overheating or temperature warning | Low coolant, leak, failed fan, water pump or thermostat | High. Stop and switch off. |
| Oil pressure warning light | Low oil level or oil pressure | High. Stop and switch off. |
| Knocking or ticking | Low oil, worn bearings, valve train problems, wrong fuel | Medium to high, depending on how loud. |
| Burning oil or blue smoke | Worn piston rings, valve seals, turbo seals | Medium. Monitor oil level closely. |
| Rough idle or hesitation | Spark plugs, coils, vacuum leaks, dirty sensors | Low to medium. |
Oil consumption
All engines use some oil, but some use a lot. Excessive oil consumption has been a known issue in a number of engines over the years.
- Check your oil level with the dipstick or the car's oil level display at least once a month, and before long trips.
- Write down how much oil you add and the mileage each time.
- If you are adding oil between changes, tell the dealer and ask for an oil consumption test. This is often required before warranty work is approved.
- Ask whether there is a service bulletin or warranty extension for oil consumption on your engine.
Some manufacturers consider fairly high oil use to be "normal" for certain engines, so keep records. Running low on oil can destroy an engine and, in some cases, cause it to fail while driving.
Overheating
If the temperature gauge climbs into the red or a warning appears, pull over safely and switch off. Driving an overheating engine even a few miles can cause severe damage.
- Do not open the radiator or coolant cap while the engine is hot. Hot coolant can spray out and burn you.
- Once it has cooled, check the coolant level and look for leaks.
- Steam, a sweet smell or a puddle of colored fluid suggests a coolant leak.
- White exhaust smoke with a sweet smell, or coolant loss with no visible leak, can mean a head gasket problem.
The check engine light
The check engine light comes on when the engine computer detects a fault, often related to emissions. A steady light is not usually an emergency, but get the codes read soon. Many auto parts stores and any repair shop can do this.
A flashing check engine light is different. It usually means a severe misfire, where unburned fuel can overheat and damage the catalytic converter. Slow down and get the car checked as soon as possible.
What to do
- Write down what happens. When, at what speed, warm or cold, and which lights came on. A video with sound helps.
- Check for recalls. Use our VIN check or nhtsa.gov/recalls. Some stalling and fire risks are recalled.
- See if other owners report the same thing. Look at engine complaints for your model, for example /hyundai/sonata/2013, or across all vehicles on engine problems.
- Get a diagnosis in writing. Ask for the fault codes and what the shop found.
- Check warranties and bulletins. Engines are covered by the powertrain warranty, which often runs longer than the basic warranty. Ask about extensions and bulletins. See TSBs and goodwill repairs.
Typical repair costs
These are typical rough ranges that vary widely by vehicle, engine and location. Get a written quote.
- Reading fault codes: often free at parts stores, or a diagnostic fee at a shop, commonly around $100 to $200.
- Spark plugs or ignition coils: often a few hundred dollars.
- Water pump or thermostat: often several hundred to over $1,000.
- Head gasket: often $1,500 or more.
- Replacement engine: often several thousand dollars, and well over $5,000 for many vehicles.
Report it
If your engine stalled or lost power while driving, file a complaint with NHTSA. It is one of the ways stalling defects come to light. And share your experience here too, with the mileage and repair cost if you know them, so other owners can spot the pattern sooner.
Questions and answers
Is it safe to drive with the check engine light on?
If it is steady and the car drives normally, you can usually drive carefully to get it checked soon. If it is flashing, slow down and stop driving as soon as you safely can, because it usually means a severe misfire.
What should I do if my car stalls while driving?
Turn on your hazard lights, steer firmly to a safe place using the car's momentum and press the brake hard. The steering and brakes still work but need more effort. Try to restart once stopped.
How much oil consumption is normal?
It varies by engine and manufacturer. If you are regularly adding oil between changes, keep a record and ask the dealer for an oil consumption test.
Can engine stalling be a recall?
Yes. Stalling while driving is a safety risk, and some stalling problems have led to recalls. Check your VIN and file a complaint with NHTSA if it happens to you.