Do engines still have a "break in" period with regards to gas mileage?

Question

In other words...will a vehicle get better gas mileage after it has been driven x number of miles? Or is that simply something of the past....or was it ever something more than urban legend?

Answer 1

New cars are tight. It takes several 100 miles to get things working a little easier. Once parts have been used some they are a little easier to turn and it takes less force to turn them. Then the gas goes up a little. good luck.

Answer 2

It's not an urban legend. It takes up to 5,000 miles for the piston rings to break in and smooth the honed surfaces of the cylinder walls. After that period the rings seal better and the piston / ring drag lessens. After the initial break-in if you choose to switch to a full synthetic motor oil your mileage will improve somewhat. Depending on the motor you can expect up to 5 miles per gallon on sustained trips after the engine has gone the initial 5,000 miles and the addition of synthetic oil at the first oil change.
Be sure you drive at least 3 - 4,000 miles first on the oil that came in the crankcase. That last sentence could be urban legend also as many new cars come with synthetic oil from the factory. The Dodge Viper and the Chevrolet ZO6 Corvette specifically.

Answer 3

the "break- in" period for a new car has nothing to do with the fuel mileage. When you build a new engine, there is a period when the piston rings wear themselves to perfect conformity to the cylinder walls. This is called ''seating" the rings. If the rings are not properly seated then the car will never develop it's Target compression and the engine will usually develop a smoking from the tailpipe syndrome that will never go away. Under normal driving conditions, proper seating will generally happen in the first 500 miles.

Answer 4

Answer to your question is yes, and no. If you driving habbits do not change and you have the same car it will show a bit (5% or less) better mileage after 20-25K because initial wear of the engine and transmission settled in. Then it will stay flat for the next 20-40K untill your engine is due to the maintenance, like timing belt change, spark plugs replacement, etc. If you got your car brand new with less then 100mi and you are planning to keep it for long, then it is advisable to "break it in" as to not to race it or overload it untill the first oil change, as recommended by car manufacturer, not your dealer. There is no "break in period" like old ( before 90th) cars had. I hope it answers your question

Answer 5

Yes there still is a break-in period on new cars. It usually take about 24 hours of drive time to fully break a car in. Once the rings seat fully, then you should see a 1-3% increase in fuel economy.