Running in a new car

Question

I just bought a new 2020 Subaru Forester and the manual mentions this (an only this) about new vehicle break-in

For the first 1000 miles:

• Do not race the engine.
• Do not drive at one consistent engine or vehicle speed, either fast or slow.
• Avoid starting suddenly and rapid acceleration, except in an emergency.
• Avoid hard breaking, except in an emergency.

These points seem to match an answer from 2011

I generally understand these points and especially the one about not driving at a consistent speed in order to not wear the engine adversely. However in 2 weeks time I am planning to do a road trip in the South West of the US that is about 500 miles each way of mostly freeway driving (80mph limits) and as such I am going to run into conflict with the point about the consistent speed.

I know that these points are general guidelines, but leading up to this trip how should I structure my driving:

• Between now and the road trip should I drive as many varied miles as I can?

• When on the road trip at freeway speeds how much/often should I vary speeds?

• The first planned maintenance is 6,000miles/6months. That linked answer mentions doing an oil change on a new car very early on. Is that still a thing?

• Can I/Should I start to transition away from these points before 1,000 miles?

Answer 1

The wear pattern between the pistons and cylinders, in particular, depends on the engine speed and load.

When you are running in the engine, you want to wear away any "high spots" evenly everywhere they occur. If you run at a constant speed and gas pedal position for a long time, you may not be doing that.

A long trip on flat roads at a steady 80 mph is not really a good way to run in an engine. If you are prepared to vary your speed in a range between say 60 and 80 every few miles, that would be better. Even changing between the highest two gears at a every few miles would be better than nothing, if you have a manual transmission. It does no harm to let the engine rev high (but not right up to the red line!) so long as it is not working hard.

(If you have a manual transmission, you also need to run it in using all the gears, which happens naturally in stop-start driving conditions)

The more miles you can clock up before that long trip doing typical urban cycle stop-start driving, or constant speeds on roads with different traffic conditions between say 30 and 80, the better for the running in process.

For the first service and oil change requirements, read the manual. The first scheduled service and oil change from new on my last car was at 18,000 miles. I checked that with the dealer who said that for that car manufacturer, the "first oil change at 1000 miles" thing was now history. YMMV of course.

If it is due at 6,000 miles, it may be worse to bring it forward, because you want to get rid of all the gunk and wear particles from the new engine in the first oil change, and if it takes 6,000 miles to get it all dissolved in the oil and/or trapped in the oil filter, an earlier change will be leaving some of it behind until your second oil change.