Skip the auto shop - Our mechanics make house calls

Q: Doesn't start when it is cold out

asked by on

My truck doesn't want to start when it's cold. I try to start it but it doesn't turn over. It'll start with no problem when it warms up. My car has an automatic transmission.

A: Hi, thanks for writing in. Electricity is h...

Hi, thanks for writing in. Electricity is heavily dependent on temperature and other atmospheric factors. Temperature being the most important. Most of the time this sort of problem occurs when the vehicle is hot though. Either way, the diagnosis is the same process. The first thing to do is test the battery as it is the most affected by temperature. The best way to test a battery is with a load tester, (carbon pile or other machine) and a hydrometer which is a measurement of the weight of the battery fluid in comparison to distilled water.

Once the battery has been thoroughly tested, replace it, charge it or continue to the next stage if it is good. A simple test is to tap on the starter while someone is attempting to crank the motor. If the starter takes off, you need a starter. The brushes inside the starter will stick and tapping on it will free them.

With no crank conditions, it is always a bad connection. The question is where is the bad connection. An easy trick to locate it, if electricity is flowing at all, if it is not, this won’t work, is to hold the key in the crank position for at least thirty seconds. Sometimes less, sometimes more. If some electricity is flowing in the circuit, the connection that has high resistance will become hot. Even if this connection appears good, it is not and a thorough cleaning with sand paper is often all that is necessary. Check the battery posts, the connection at the starter and the positive battery cable. These are the most common culprits for this.

If you have come this far, you will now need a wiring diagram and a test light. Maybe a multimeter, but that takes some experience to use effectively. If you haven’t done this sort of diagnosis before, I recommend booking an appointment with one of our technicians for a Car is not starting inspection

Good luck!

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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

Get a quote

What others are asking

Q: Brakes not working

If there is not enough engine vacuum then the brake assist will not work. A leaking vacuum hose needs to be replaced as soon as possible. Once that is replaced, the brakes should start working again. If there is still...

Q: Car would not respond when I turned the key...Tried 2 or 3 times same...came back 1/2 hour it is fine.

Hello! An intermittent failure of a start response can be many things - a bad ignition switch, starter solenoid, or in your case - the keys use a "raised-chip" design for security. With years of wear, the key/ignition switch become...

Q: Brake light in dash on constantly - Pedal has longer travel as if the diaphragm is not there

Hi there, The light may be illuminated because of a false reading coming from the brake fluid level sensor if there is a warning with a good brake fluid level. Otherwise, the parking brake mechanism may be sending a false...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...