So you have a new car and you are wondering if the old adage is true? Do new car engines need to be broken in?
Yes, all new and rebuilt engines will need to be bedded properly in order to ensure the best compression performance and that the piston rings are seated correctly.
If you do not heed the warnings from the car manufacturer and owners manual you could be causing future issues like oil consumption and excessive blow-by if the piston is not bedded correctly in the engine.
So it is true, engines in new cars must be broken in for the first thousand miles, but how long does it really take? Do you need to warm up the engine before driving? What about oil changes? We will dive into the facts and figures on why it's important to vary your driving habits but not baby the engine either.
Myth of Break In Period
There is a big debate on whether or not the break in period is necessary.
While modern engines are more sophisticated and the engine tolerances are more precise, breaking in an engine is suggested by ALL car manufacturers in order to ensure optimal performance and longevity of your engine's life.
TIP: I recently changed my Vanos seals in my BMW and the vendor did include a reminder to take it easy on accelerating for the first 200 - 500 miles. This indicates that even seals need to be seated in order for the Vanos to perform well with the oil seals.
While engine rebuilders might state that most of the break-in happens in the first 200 miles, check your owner manual on the suggested break-in period. Some will vary from 500 miles to 1000 miles or more.
With today's modern engines, they are most likely using synthetic motor oil that contains detergents and additives that do not require it to be changed until thousands of miles have been driven.
Why does a new engine need to be broken in?
My analogy to breaking in a new engine, is compared to breaking in a new pair of shoes. You want to ensure that your shoes wear evenly and your foot adjusts to the leather and the soles.
When an engine is built, either from the factory or a shop that rebuilds engines, there are hash marks on the cylinder wall. Typically, cylinders are smooth after thousands of miles are driven, but freshly built, the cylinders are honed.
Honed cylinder walls allow the engine's oil to grip onto the cylinder walls as the piston rings move up and down. The piston rings then scrape the walls and wear down these honed hash marks during the break in period. The cylinder wall will end up smooth after the break in period.
As material is worn down, the piston rings and the cylinder walls are mated, allowing just enough clearance for oil to lubricate the space between the piston and the cylinder. This is why it's so important to allow the engine to bed itself.
So back to the shoe analogy, as your foot applies pressure to the insoles, your shoe begins to conform to your foot. And after hundreds of steps, it's as comfortable as an "old" pair of shoes.
How do I break-in a new car engine?
You will need to check your owners manual for the break in procedure. But most break in procedures are the same.
There are a few key points to remember when driving your new car and allowing the car's engine to break-in.
Warm Up Car
Engine temperature is critical when you first have a new car. Cold starts and engines require a little more time to have the oil flowing freely throughout the engine passages. You will want to start your engine and let it idle or warm up for at least 30 - 60 seconds.
Most modern engines should have enough oil pressure by 30 seconds and it's safe to drive moderately after that. You don't have to excessively warm up the engine for 3 minutes because most modern engines run thinner oil.
TIP: A good rule of thumb is to warm up the engine and when the throttle RPM stabilizes, then you can normally drive away. This is about 30 seconds after the cold starts.
Vary Your Throttle
Since the main objective is to bed the piston rings and remove the home on the cylinder, you will want to vary your throttle range and RPM. Just like a muscle, you want a full range of pressure in the engine so that the piston rings can continue to mate with the cylinder walls. Avoid constant speed.
Excessive throttle or WOT will not speed up the process, you will want to keep the RPM under 4,000 as mentioned previously.
TIP: In addition to varying your throttle, most car ECUs adapt to the driver's habits and style. Yes, as weird as it sounds, the car will "learn" your driving style, so it's good to drive normally and not drive like a "grandma" on church Sunday or the car will learn that driving style.
Don't Exceed 3.5k - 4.5k RPM
When you apply throttle to the engine, you demand more compression of the engine. During the break in period, you want to allow the engine to settle in before you push your pedal to the floor.
You will cause the piston rings to seat with larger tolerances and potentially lead to oil blow by or oil consumption. Stay within the owner's manual and you should be fine.
Don't use cruise control
As mentioned above, you will also want to avoid constant speed and manually adjust the throttle and put the engine through its paces. Using cruise control will not allow the engine to rev through the range and will coast at a set RPM.
If you plan to do a long drive, vary your speed and don't always stay at the same RPM. Plus, this gives you more opportunity to get used to the car and its throttle response.
Stay within Speed Limit - Don't drive excessive speeds - Higher RPM and Compression
During the break in period, we want to have the engine not work to its limit. Higher speeds may demand for higher compression, especially in the higher gears.
Stay within the posted speed limit for the first 500 miles or 1,000 miles to keep your engine safe and your driver's license intact. lol.
Avoid Towing Heavy Loads - Taxing the engine for higher compression
Again, demanding more power from the engine is fine after their break in period but premature heavy loads may cause improper bedding of the piston rings. Towing heavy will demand high compression from the engine and may cause oil to find its way past the piston rings, causing oil consumption.
If your engine is a turbo, which is a popular configuration today, you have a higher chance of this due to the boost.
Cooling Off After Long Drives - Car cool down (especially with turbo engines)
Today's turbo engines run hotter than naturally aspirated engines of the past. But it's important to let the car cool down by driving normally after a long drive.
Staying 5 mins off boost can help tremendously to allow the engine to lower its operating temperature. This is true for all engines.
Try to drive like you would under normal driving conditions after a hard or long drive so that the engine can cool itself down. Plus this is better for turbos in general.
How Long Does It Take to Break in an Engine?
As mentioned earlier, it takes between 500 - 1,000 miles to break in a new car's engine. If your car's engine was rebuilt, I would still follow this good rule of thumb.
Investing in the proper 1,000 miles will pay for itself by avoiding the potential for future issues of oil consumption and blow by.
TIP: Even on used cars, I typically suggest changing the oil too and allowing fresh oil under your new ownership. While you are not breaking it in, you can start fresh. For used cars, you can also look to reset throttle adaptations to help the car learn your driving style under normal driving conditions.
Remember, you don't have to change the oil after the break-in period on new cars. However, some high performance shops might suggest an oil change if your engine was rebuilt.
Other Benefits of the Engine Break In Period
In addition to properly breaking in your engine, it will also be a good time to break in your tires as well as your car's braking system.
Tires - Car tires are typically broken in after 300 miles. There are elements in the tire that come to the surface to ensure the tire remains resilient and flexible.
Rotors and Brakes - The car's braking system also is broken in 300 - 400 miles. This allows even wear across the rotor surface and pads. By breaking the brakes in, it will avoid pulsing or juddering when stopping.
How to Extend the Life of Your Car's Engine
After the break in period, you can enjoy the full thrill of your car's acceleration and horsepower. It's good practice to allow the engine to warm up after a cold start or sitting overnight.
Secondly, you will want to make sure your engine is at operating temperature before you WOT or push the engine.
Changing your oil at a shorter oil change interval (OCI) is also helpful. While full synthetic can last longer, most car enthusiasts have OCI at half the time. This is good car maintenance practice and a cheap investment.
For example, if it calls for 15,000 miles, you might consider 7,500 as a suggestion. This is especially true for short drives and shorter distance trips. These short trips are taxing on the engine.
In conclusion, I hope you now have a better understanding of how to break in your new car engine. Be sure to follow the tips I outlined and you should be good to go. Thanks for reading!
Comment below for your thoughts on breaking in an engine