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There has been a longstanding debate on whether you should warm up your car before driving it. Some people say that the necessity of warming your car up before driving it is a myth. Others will let their cars idle for 30 seconds before driving. So, should you warm your car engine before you start driving?
Well, it all depends on how old your car is and the type of climate you live in. In this article, we will give you information on whether you should warm your car engine and why. Keep reading to find out more.
Fuel Injected Cars vs. Carbureted Cars
Older cars that ran on carburetors had chokes on them. These chokes restricted the airflow into the throat of the carburetor which pushed a large amount of fuel from the main jet into the combustion chamber to warm up the oil in the engine.
Once the engine was warmed, you’d have to manually switch the choke off. A couple of years went by and carburetors were redesigned with electronic chokes on them so you wouldn’t have to manually switch them on and off in cold weather.
Even though technology advanced with automatic carburetors, you still had to warm the engine before driving. This is because automatic carburetion still didn’t perfect the air and fuel ratio which is necessary for the car to run well, without damaging the engine by running fuel too rich or lean.
Then fuel injection was invented. But older cars with fuel injection still weren’t designed with electronic systems to measure how much air was coming into the engine. Older fuel injection cars typically ran with one oxygen sensor to monitor the air-fuel ratio.
But modern cars have many different sensors to monitor how much air and fuel enters the engine to optimize the vehicle’s performance. The sensors in modern cars are a lot faster and more accurate, so the engine will always get the correct amount of fuel no matter what the temperature is.
Based on this information you can see you don’t have to warm your car up before driving if it’s a modern fuel injected vehicle. But for carbureted applications you have to warm up the engine before driving and here’s why.
Why Carbureted Cars Need to be Warmed Up Before Driving
Older engines in colder climates need to get as much lower viscous oil through the vehicle’s system as possible. In cold weather, gas doesn’t evaporate as well so the liquid is more difficult to vaporize in lower temperatures.
When temperatures are low and the engine is cold the combustion will be uneven. The carburetor chokes off some of the air to compensate for the uneven combustion and will run richer fuel but less efficiently.
As the system heats up, the performance of the car starts to improve. Once the car is warm enough the fuel will vaporize and the car will idle smoothly. Since carbureted cars don’t have the advanced sensors that modern vehicles do, you should always warm up the engine before you drive.
What Will Happen if You Don’t Warm Up Your Carbureted Car Before Driving?
Gasoline is a solvent, so when extra fuel gets onto the cylinder walls it washes away the oil from the cylinder and the pistons. If there’s no oil on the cylinder walls it won’t protect the component. When the oil is at a lower temperature it’s more difficult for it to be replaced.
The more you drive with your engine cold the faster the cylinder and piston will wear out. Simply leaving the engine to idle doesn’t warm it up efficiently, so the car’s application will remain cold until you start driving.
If your car runs rich with gas it can cause oil dilution. This happens when fuel passes through the pistons and mixes in with the oil. Diluted oil can result in a thinner consistency with less film strength. This results in application wear and accelerates the oxidation of the oil which means the liquid will break down quicker.
Warming Up your Car Correctly
Warming up your car before you drive only has to be done in extremely cold weather with temperatures that drop to -32°F.
To warm up your car, turn the ignition on and let your vehicle idle between 20 & 30 seconds. This process is to ensure that the oil in your car’s system is flowing. The engine will heat up faster if you drive the car at low speeds.
By driving slowly the oil will heat up faster and the operating temperature will rise quicker. The process of driving at a slow speed for a few minutes will prevent engine wear.
If you live in a region where it snows, simply turn your ignition on while you clear the ice off of your car’s body and windows. This will give your vehicle plenty of time to warm up the oil so it can flow through the car’s system to optimize performance and prevent wear.
What Not to Do when Warming Up Your Car
You don’t want to put unnecessary strain on your car engine. That’s why you should never drive at high speeds when it’s cold. The car engine warms up better in six to 10 minutes while you’re driving, so to prevent wear, drive slowly for a few miles before speeding up.
Modern high-performance cars have an integrated rev-limiter which only allows the car to reach full RPM when the engine is at a certain temperature. The rev-limiter ensures that you don’t drive your car at high speeds when it’s cold, so it can prolong the service life of your vehicle’s engine.
Using the Correct Oil for Your Car’s Specs
Another aspect you should watch out for if you live in colder climates is using the incorrect oil for your car. Excellent quality oil is crucial for protecting your car’s engine in cold weather. To select the correct engine oil for your car you must understand how the liquid is made.
In this next section, we will go through the different components of engine oil and the type you need to run your engine in cold weather.
Your engine oil has to function under extreme temperatures and pressures. For vehicles running in cold and hot weather, the engine oil must be designed to adjust to various temperatures. This is so the liquid can protect the engine’s components and optimize vehicle performance.
Know that engine oil has a difficult time flowing in colder temperatures, but it runs well in warm conditions.
If you’re driving with heavy loads it can affect the flow of the oil more. The oil flow resistance calculation is referred to as viscosity.
In America, there are various standards to engine oil, with the latest being SN, designed for all gasoline petrol applications. The oil you purchase will have to be equal or better than previous standards such as the following:
- SJ Vehicles manufactured before 2001
- SL for most lightweight passenger vehicles
- SM for vehicles manufactured between 2002 and 2009
To find the correct engine oil for your car, refer to your owner’s manual. Select oil with at least two multi-grade specifications designed for your car’s engine. Your owner’s manual will recommend oil that will state it’s compliant with SN of API products.
There’s also a numerical system for grading engine oil according to its viscosity. Numbers 0, 5, 10, 15 and 25 followed by the letter ‘ W’ are winter-grade oils. After the letter W, it will give you another number which is the hot temperature oil grade. The most common oil grades are 5W-30, 5W-20 and 0W-20.
What Happens if you Use the Incorrect Engine Oil for your Car?
If the cold viscosity of the oil is too much your car won’t start in lower temperatures. And if the hot viscosity of the oil is too much for your car’s specs when you start your vehicle the oil will lose its strength. The oil won’t run through the components of your engine to accurately lubricate the vehicle’s system. This will result in the oil being burnt.
The viscosity rating is what’s important, such as ‘5W-20’.
If you run the incorrect oil in your engine for too long the gas won’t be able to lubricate the components in your engine, which will result in wear.
So, to recap this article: modern cars can be driven immediately after start-up in colder temperatures. The engine will warm up better when driving at low speeds for at least six minutes to heat up the engine oil for efficient system lubrication.
Remember to refer to your user manual to find the correct engine oil for your car to protect your engine from corroding.
For older vehicles that still have a carburetor, it’s advised to warm up the car for at least 30 seconds before driving to get the perfect fuel to air ratio. Your car will drive better with no loss of power during the winter months and it will prolong the service life of your engine.
Now you know how to look after your type of car. Safe driving everyone!