New Car Break-in

One of the things I was very concerned about with my new Corvette was breaking it in properly - that is, driving it while it was new in a way that would would help my car obtain its best operation and longest life.  The following information is based on comments posted to the alt.autos.corvette news group (special thanks to James Crone, who, I believe, builds marine racing engines and recommends reading "Break It In Right" and "Drive it Forever" by Robert Sikorsky).  I'm sure you can find other recommendations elsewhere.  This is my attempt to summarize what I learned and did on my new Corvette.

Background

When a car is new all the parts in the engine and drive train (primarily the transmission and rear end) fit very tightly together.  As the car is driven these parts start to wear against each other.  The goal of new car break-in is to minimize wear that can damage the parts.  Not only can this prolong the life of your car but it can improve the performance of it as well (like better power and gas mileage).

The Owner's Manual provided by GM with my Corvette said only to drive the car under 55 MPH for the first 500 miles and to vary the speed.  This write-up expands upon that including how to drive the car when the engine is cold, how to drive it in general and what kinds of maintenance to perform.

Cold Starts

The most detrimental time for your new car is when the engine is cold.  You want to minimize the time it takes your engine to get to normal operating temperature and be easy on the engine until it is up to temperature. The following is recommended:

• Avoid cold starts - plan your driving such that you can start your car and go for a moderately long drive.  Try to avoid short trips.
• Drive the car immediately - idling the engine causes uneven engine wear.  Get yourself ready to leave (buckle up your seat belt, adjust the seat, etc.) before turning on the engine.  When you turn on the engine put it in gear and leave immediately.
• Accelerate moderately - never use more than 1/4 throttle while the engine is cold.  Excessive throttle can cause engine glazing and uneven wear.
• Shift gears at under 2500 RPM - don't over-rev the engine.

Driving

During the first 500-1000 miles your engine and drive train parts are establishing a 'fit' that they will have the rest of their lives.  Try to follow the following procedure for the first 1000 miles or so.  If your car uses synthetic oil you may want to extend this even longer because synthetic oil slows engine wear.

• Keep your speed under 55 MPH for the first 500 miles.
• Don't accelerate overly hard.
• Avoid full throttle starts from a dead stop at all costs - there will be time for that later.
• Continuously vary your speed - it's tough on you and the people following you but try to change speeds constantly.  The worst thing you can do is use your cruise control.
• Drive on slow-speed trips as well as moderate-speed trips - so you can use as many gears as possible.  After 500 miles, add high-speed trips, too.
• Do not exceed about 3500 RPM.  Make your shifts smooth and deliberate - not only are you breaking-in your engine, you are breaking-in your transmission and rear end.
• Never lug your engine - if you have a manual transmission, try to keep the transmission in a moderate RPM range.
• Try to drive during cool temperatures - overheating is the enemy of new engines which tend to run hotter until they are broken-in.
• Try not to use your air conditioner - this helps reduce the temperature of your engine by eliminating the load of the compressor.
• After a long highway run, let your motor idle for a few minutes - this is an exception to the no-idling rule which lets the engine cool down a little.

James Crone recommended a procedure for the first 100 miles or so where you drive at 2000 RPM then increase to 2200 RPM, 2500 RPM and 2700 RPM and then the reverse.  He recommended repeating this 'pyramid' constantly staying at one RPM for only 20 seconds or so and never exceeding 2700 RPM.  (I told you this would be tough).

I followed Mr. Crone's recommendation as best I could for the first 1000 miles.  The first 500 miles under 55 MPH, the second 500 miles exceeding 55 MPH.  Because my Corvette uses synthetic oil I continued 'babying' my car for the next 1000 miles.

After the first 800 miles or so, try the following 'ring seating' exercise:

• At cruising speed and RPM (like 40 MPH and 2000 RPM) slowly depress the pedal until it is floored, hold it there for 4-5 seconds and then slowly release the pedal .
• Do not slam the accelerator pedal hard or release it quickly - this can cause damage.
• Do not exceed about 3500 RPM.

Maintenance

As the engine and drive train break-in they flake off little bits of metal which are trapped in the lubricants.  There can also be dirt or other contaminants introduced in manufacturing.  If left there, these metal flakes and contaminants may deposit themselves on surfaces and cause uneven wear.  Early oil changes reduce this risk.  The following maintenance procedure is recommended:

• Add a 'Top Cylinder' lubricant to your gas for the first 500 miles - this helps even the wear in the cylinders and better ring seating. James Crone recommends 'Marvel Mystery Oil' - 8 oz. per tank (19 gal on the Vette).
• Change the engine engine oil frequently during breaking - at 400 miles, 1200 miles, and 2500 miles.
• Change the transmission and rear end oil at about 3000 miles.

As a side note, if you like to change the oil yourself - you may want to consider letting your dealer do it the first time.  I'm told that the oil filters are fitted so tightly in the factory they can be very difficult to remove.  My dealer told me even they have problems sometimes.

When should you change the oil after break-in?  There is a lot of debate about this.  Synthetic oils claim to have a lifetime of 10,000 miles.  However, acidity builds up in oils so it is a good idea to change them more frequently.  The most frequent advice I see is to change the oil every 3000 miles or so and at least once per year.  Changing the oil frequently is a small price to pay for a longer lasting/better performing engine.

The bottom line

Break-in your car right and you'll have a long-lasting, better running vehicle.