When the car won’t start on a freezing day, you are not alone. Cold weather can affect starting systems.
With a simple understanding of how extreme cold can impair the system, you can fix the starting problem so that starting won’t be a challenge in even the coldest of temperatures.
Starting Problems (Cold vs Hot Temperatures)
Most people don’t know that extreme temperatures affect the starting capability of a car. In general:
- Cold temperatures slow down the chemical action inside the battery, which makes it more difficult for the car battery to supply enough power. This is why car batteries are rated by CCA (cold cranking amps).
- Hot temperatures on the opposite end can cause the fuel in the fuel lines and injectors to vaporize and prevent the engine from starting. This condition is referred to as “vapor lock”, and it occurs when tiny air pockets within the fuel lines outnumber the liquid fuel, disrupting the fuel flow for the engine.
7 Reasons Your Car is Hard to Start in the Cold Weather
There are several reasons why it is difficult to get a car to start in cold weather. Here are seven common reasons.
#1. Weak or Dead Battery.
A bad car battery is one of the most common causes of a car not starting well in cold weather.
In cold conditions, the chemical reaction slows down, which means that the battery cannot produce or send enough power to the starter motor. If the battery does not have enough power to turn the engine over, starting the car could be problematic.
You must keep your battery in shape. Regularly check the terminals and cables for corrosion or damage and clean them if necessary. Use a battery tester to get a voltage reading on the battery, and charge the battery to see if it holds a charge. If your battery is weak (and at least a few years old), get it replaced ASAP, or you may be left stranded.
Related Post: Does the Cold Weather Kill Your Car Battery?
#2. Failing Alternator.
Your car’s alternator is responsible for charging the battery while you drive. It is also responsible for supplying power to the electrical components in your vehicle, including the lights and the radio.
When the electrical system is running, the alternator provides a voltage higher than the voltage of the battery, which allows for electric current to flow into the battery to charge it.
If the alternator is failing, it will drain the battery, especially in cold weather, especially if the battery was weak to begin with. There are instances where, if your battery appears to always be dead, more than likely, the alternator will be cited as the root cause.
#3. Bad Starter Motor.
It should be abundantly clear that a starter motor will be necessary to start a vehicle. If the starter motor has been fading on you, it is just going to have a difficult time turning the engine over, especially in cold conditions.
What you will often hear when you attempt to start the engine is that there is a whining noise or a clicking sound.
While a faulty starter causes issues in any weather, it becomes especially undesirable when temperatures begin to drop.
#4. Bad Starter Solenoid.
The starter solenoid directs electrical current to the starter. An altered solenoid may prevent your car from starting in cold weather.
A mechanic will often be needed to test and double-check, and see if it is the starter solenoid or the starter motor itself.
#5. Low fuel pressure.
When there is low fuel pressure, your engine may not be receiving enough fuel to start and run.
Cold temperatures can worsen fuel pressure problems, as the fuel can thicken and become more viscous, impeding fuel flow and possibly keeping the engine from starting.
#6. Wrong or old engine oil.
When the temperature gets low enough, oil will thicken and become more viscous. This can affect the engine’s ability to properly circulate oil, making it more difficult to start the engine, which is why it’s important to stick with the recommended oil for your vehicle.
The owner’s manual will state the recommended oil for the car as well as the viscosity rating of the oil. It may be okay to use a thinner oil with a lower viscosity rating (e,g, 5W-30 or 5W-20) in areas that have extreme cold. You may also consider using synthetic oil, as it is meant to perform better in cold weather.
Synthetic oil is designed to act more like a liquid at lower temperatures, and it helps to make sure the engine gets the lubrication it needs to start and run smoothly. Also, be sure to follow the recommended oil change intervals provided by the manufacturer.
Over-time, motor oil will break down and mix with contaminants, which will thicken the oil and mix with the contaminants. More work must be done by the engine to pump the older oil, which makes for more difficult engine starts.
#7. Bad coolant temperature sensor.
A faulty temperature sensor may give incorrect information about the temperature of the coolant. This could lead to hard engine starts in cold weather. Check the coolant temperature sensor and replace if necessary.
The coolant temperature sensor measures the temperature of the engine coolant and sends that information to the Engine Control Module (ECM). The ECM then uses the temperature and residual information to control and adjust the fuel injection and ignition timing to achieve optimal success in diesel engine operation.
If the coolant temperature sensor is faulty, it might send incorrect information to the ECM. Bad temperature information causes the ECM to send incorrect fuel and timing information to the engine, which might cause problems starting the engine when cold.
Dealing With Difficult Starts
If you have a car that is difficult to start when it’s cold out, you may find this frustrating. These are some simple ways to deal with difficult starts related to battery, alternator, and starter motor issues so you can get back on the road.
Jump Start
If your car isn’t starting due to a battery issue, sometimes it just needs a jump start to get it going again. To perform a jump start:
- Locate another vehicle with a good battery and have it parked facing your car, but not touching.
- Ensure both vehicles are turned off and in park (or neutral for manual transmission).
- Connect one end of the positive (+) jumper cable to the positive terminal of the good battery and the other to the positive terminal of your dead battery.
- Connect one end of the negative (-) jumper cable to the negative terminal of the good battery, and the other end to a clean, unpainted metal surface on the engine block of your vehicle. Some vehicles in more recent years have a specific grounding bolt for jump starts, and it is generally labeled with a (-).
- Start the vehicle with a good battery and let it run for a few minutes.
- Attempt to start your vehicle. If it gets going, allow the two vehicles to run for a few more minutes to help charge your battery.
- Once your vehicle is running, you can disconnect the jumper cables in the opposite order that you connected them.
Alternator or Starter Motor
If the jump-start fails or your battery seems healthy, the next problem could be the alternator or starter motor. Do a few of these things:
- Check the alternator belt for wear and tension; change or adjust the belt.
- Check all wiring connections going to the alternator and starter motor; make sure they are clean and secure.
- Test the alternator output with a multimeter. If the output is below the proper voltage level, this may be difficult to start.
- Check the starter motor; if there are strange sounds when you are cranking to start the car, or if your motor is slow to crank over starting, this may point to a starter motor issue.
In some cases, a mechanic might be needed to help you diagnose and fix the alternator or starter motor.