We’ll admit it. We don’t like getting into a cold car. Who does? So, should you warm up your car engine, first?
The question is how to get around sitting in a cold car for too long all bundled up. Should you start the car or truck and let it idle for 15 minutes and let the heat buildup? If you have a remote start on your vehicle, the temptation to peek out the window and hit the start button is very real. Sadly, idling your vehicle for minutes before you jump in is exactly the opposite of what you should do.
Cold Engines Use More Fuel Than Warm Engines
If you’ve ever ridden or driven in an older vehicle with a carburetor, you may have had to manually apply the choke to have more fuel enter the carburetor. Then, during the later years, carburetors had electric chokes which were easier to deal with. It never fails that you’d forget to turn off the choke, and either flood the engine with fuel or foul a set of spark plugs.
On a colder engine, gasoline doesn’t evaporate well. So, it’s harder for air and fuel to mix well to meet the optimum stoichiometric ratio of 14.7 parts of air to 1 part of gasoline. That’s why applying the choke on carbureted vehicles adds more fuel, to get around the problem. On fuel injected vehicles, the computer system (also known as the engine control unit or ECU) compensates for colder temperatures in the same manner. It adds more gasoline.
Adding more gasoline does get the job done and helps to warm your engine up faster. But it isn’t necessarily the best for the long-term health of your engine. Gasoline is a powerful solvent. Consequently, if there’s too much liquid gasoline in the combustion cylinders, it can wash away the engine oil lubricating your cylinder walls and pistons. It can also increase the wear on your bearings if too much gasoline gets into your engine oil.
How Should I Warm Up My Car Engine?
If you’re not supposed to idle the engine for a long period to warm it up, how should you do it? The simple answer is ‘slowly’. Driving your vehicle slowly is the easiest way to get it up to temperature. At around 40ºF (4.4ºC) your engine will start to achieve the optimum air-fuel ratio. When you first start your engine, allow the oil pressure to build up before starting to drive away. That should take only a few seconds for the oil pressure to build up. Once it’s showing good oil pressure, you can start to slowly drive. The biggest takeaway is that you don’t want to use more gas pedal than needed. Again, more gas equals more problems.
If you’re into data like we are, you want to know more than just ‘don’t floor the gas pedal’ and it will be warm in no time. How long is that really? Believe it or not, most cars can warm the interior of a vehicle to 70ºF in 10 minutes or less with slow continuous driving. Just allowing the vehicle to idle to that point takes almost 30 minutes. Three times as long?! We don’t have that kind of time in the mornings! We’ll let the vehicle idle while we scrape the windows clean, and then we’re buckling that seat belt to hit the road.
Keeping your engine well protected from cold weather doesn’t have to be complicated. Choose an oil like AMSOIL 5W30 Signature Series that has a low pour point to ensure it flows easily in your engine on those cold mornings. If you’re not sure which oil is the best for winter driving, give us a shout at Buy Great Oil. We are here to help find the best maintenance program and products to protect your vehicle in every season. We are your local AMSOIL dealer.