Should you warm up your car engine in the morning?

In Summary

•When a modern engine is started for the first time in the morning. the lubricating oil does not go through the filter.

•An oil pressure sensor valve is still closed hence creating a small detour route for the engine oil to supply the lubricating oil to the crankshaft and the main bearing is taken

A Subaru.
A Subaru.
Image: BOOSTED AUTO

Are there any benefits of warming up your car in the morning before you start your day or is it just a myth?

Let’s find out.

If you are a daily driver, chances are, a friend has mentioned to you that you drove off too fast before your engine warms up. The probability of this friend being 40 years and above is high. The truth is, modern cars do not require you to warm up before driving.

The reasons are below:  

 Electronic fuel injection utilizes the control unit (brain box) to monitor all the sensors (inputs) on the engine and determines how to adjust all the actuators (outputs) on the same engine for proper operating of the engine.

When a modern engine is started for the first time in the morning. the lubricating oil does not go through the filter. An oil pressure sensor valve is still closed hence creating a small detour route for the engine oil to supply the lubricating oil to the crankshaft and the main bearing is taken, this is the most vital part in the engine that should get oil just before the engine picks momentum, this takes less than one second.

 After the vehicle has started, the control unit automatically adjusts the engine revs to above 1000 revs per min so that the car comes to its optimum running temperature as quickly as possible. Unlike the ancient cars that utilised the venturi effect at the carburetor to atomize petrol, the modern car has injector nozzles that are electronically basing on the engine temperature and engine load.

 Just before the engine revs dropdown suppose you engage a gear (load) the revs automatically drop down to give you ample time to drive your car but at this time the computer limits the performance of your engine for around 10 minutes or thereabout in your journey just to make sure that your car warms up to optimum. It’s advisable that you drive your car gently to allow the engine come up to working temperatures before you start pushing it.

Now the biggest question is why should you not idle your car in the morning. There are so many side effects associated with the prolonged engine idling in the morning.

When an engine is cold the control unit tends to spray too much fuel at the nozzle to compensate for the low temp. even though the computer tries to keep everything within stoichiometry, still the engine burns with too many hydrocarbons.

These hydrocarbons are the largest contributor of damaged catalytic converters that are fitted in every modern car, the other setback of the hydrocarbons is that they are extremely harmful to the human respiratory system and can cause serious injuries when many cars keep idling in an enclosed apartment parking every day for prolonged periods, too much idling will also mean too much compensation fuel hence too much fuel used at the end of the day.  Also when the engine is idling, this means the temperatures won't rise to optimum easily because there is no load. This means the engine is running cold and a cold engine is associated with too much friction at the cylinders hence damage to the engine.

 The only advantage associated with prolonged idling would only be attaining the interior heating system during the cold season, however the car manufactures lately incorporate electrically heated seats to ensure that you get instant heat without waiting too much in the parking lots

 Automatic start-stop features are also incorporated in cars to ensure that the cars burn fewer hydrocarbons in traffic to keep the cities less polluted and prolong the life span of the catalytic converters as part of thermal management, some car manufacturers pad the engines to ensure that all the heat does not go into the atmosphere during the night so that by the time you are running the car in the morning the engine hasn't lost all the heat. This way it will be easy rising to the optimum temperature.  

In a nut shell, you don't have to idle run your car for longer periods in the morning but always keep the initial drive at a gentle speed for at least 15 to 20 minutes.