Q: Car overheating and running rough

asked by on March 28, 2016

My car is idling rough. It starts but feels like it is going to cut off. And it overheats when driving with the air on.

Car idle is rough Inspection $94.99 - $114.99 Get a Quote

A rough idle can be caused by many things. Something as simple as a bad spark plug wire or bad coil can cause a vehicle to idle rough. Since you have an overheating issue as well while driving, the problem may be more complex.

Overheating and a rough idle that happen at the same time can be caused by a blown head gasket. A blown head gasket means that the cylinder is not sealed, so the compression from the bad cylinder leaks into the cooling system. This causes a rough idle because the cylinder is not working properly.The hot compression gasses that leak into the water jackets heat up the coolant and the radiator cannot cool the engine down fast enough causing it to overheat.

Because diagnosing blown head gaskets requires special tools, I would suggest seeking help from a qualified mechanic, such as one from YourMechanic, who can help you diagnose why your car is idling rough.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Find TDC and also set cam position sensors.
Hi there. If you are just replacing the camshaft sensor then all you need to do is unbolt the sensor and install the new sensor. If you are installing a new oil pump driver under cam sensor then remove number...
Will a purge solenoid eat up gas
If the he purge valve is open all the time it may cause the fuel tank to go into a vacuum and cause the gas to vaporize more than it should. You should not see very much loss of fuel...
Intake Camshaft Position Timing
Hello. This is one of the most important aspects of your engine. If the cam timing is off enough it can keep the engine from running and even cause catastrophic engine damage. If the timing is just slightly off, then...
Check Engine Light is on - code P0405
This code could be caused by the EGR valve (https://www.yourmechanic.com/services/exhaust-gas-recirculation-egr-valve-replacement), the EGR valve position sensor, a wiring or connector issue, or even a problem with the PCM. P0405 is set when the PCM sees a voltage reading below .35 volts....
My car won't start. All the lights work, there is just a single loud click when I try to start it. Is it the starter?
If the starter is accessible under the hood, grab a friend and a small hammer. While one of you tries to crank the engine, have the other lightly tap the starter at the same time. It is possible the starter...
when should the serpentine belt be changed
The drive belts on your vehicle should be replaced every 120,000 miles. However, you should regularly perform a visual inspection of the belts (https://www.yourmechanic.com/services/serpentine-drive-belt-replacement) obviously looking for unusual wear, damage, or defects. In addition, if any noises from the pulleys...
Causes of overheating 2012 Hyundai Accent
Hi there - overheating is caused by the inability of the cooling system to deal with the heat generated by the engine. The engine itself can overheat from a stuck (closed) thermostat, or a blown head gasket (which effectively "superheats"...
My car will start up and run fine until reaches normal temperature and be hearing clicking from kick pannel and car shuts off
The relay that is clicking is the main computer PCM/Fuel pump relay. The relay may be bad or may be getting overheated from a fuel pump drawing too many amps. I suggest you replace the relay first and then see...
I have 2012 Mazda CX5. How do I change the language on the information display system from Japanese to english? Thank you for y
I believe that this would be in the settings menu on the radio or instrument cluster. I would recommend checking in your owner's manual for this particular information to see if it tells you how to do it. If the...

Related articles

How to Buy a Good Quality Cooling/Radiator Fan Motor
Fans Fans are necessary to keep the components under your car’s hood from overheating. Excessive heat can cause warping, melting, and other damage, not to mention the additional energy suck. The radiator is one of the hottest parts in the...
Symptoms of a Bad or Failing Cooling Fan Relay
Common signs include the engine running hot and cooling fans either not functioning or running all the time.
Symptoms of a Bad or Failing Low Water Sensor
If your car has low coolant without a warning, the Coolant Light comes on for no reason, or the car is overheating, replace the low water sensor.