New Car Break-In Process...
 

Having brought home a new vehicle this week, I read over my owner's manual and I find the new vehicle break in process a bit too tame. This is a Subaru but their recommendation is much like Honda's. Having owned some Fords and Fiat/Chrysler products in recent years I always found their break in procedures seem to make more sense.

The Subaru suggests easy driving for 1000 miles, keeping rpms under 4000 and light throttle (40-50 percent max ), and no highway cruise control operation. That just seems a bit overkill to me and 1000 miles is a long time to hold back. I would do it if it meant a longer engine life, but I don't think that is the case. The Fords and FAC vehicles suggested regular WOT throttle use in higher gears for short bursts of time when safe to do so, avoiding higher rpms. This makes more sense to me to get the piston rings to seat early on, and the only way to get adequate pressure on the rings is wide throttle IMO. I've been doing a fair bit of wide throttle acceleration between 2500-4000 rpms in higher gears only, and no jack-rabbit starts. I haven't exceeded 4000 rpms yet. I still think 1000 miles is a very long time to drive as easy as they want. I'll probably increase rpms after 600 miles in light duty situations to start varying engine speeds. I think getting pressure on the rings early will reduce the chance of oil burning later down the road.

What's everyone opinion on break-in procedures ?

Thanks for the great info and reply on this. I have not taken it over 4000 rpms, I will wait longer to do that based on your info. Hopefully the throttle application isn't an issue , it is pretty hard to keep throttle at such low opening for a long break in period. Do you recall your break in regimen ? Thanks again.

Engines which I've rebuilt, I run straight 30W break-in mineral-based oil. Run motor at varied the RPMs (no cruising at set RPM range). Drain at 500 miles. Replace filter and use break-in oil for another 500 miles. Check to be sure compression is good. No funky oil leaks. Temp & pressure range is good.

Replace at 1000 miles to whatever oil the engine will be using for the rest of its life. Seems to work well. No problems with early mileage oil consumption. I've never rebuilt an S2000 engine. Mostly older BMW, MB, and 911.

Like this stuff:

https://www.amsoil.com/shop/by-produ...-oil-(sae-30)/

No prob. I've actually owned a few "performance" Subies... owned an 00 2.5RS, traded that for the 02 WRX, traded that for the 05 STi. Subaru was so fun back in 00-05.... people would wave, and NASIOC had actual info. lol. Anyway, I remember following exactly what Subaru said to the letter. It drove me nuts. In fact, I believe that my dealership was suggesting even stricter rules to avoid oil consumption. What a lot of people forget, was that before the 07+ STIs decided to blow ringlands out, these EJ257 motors were running very rich and gobbled oil. Subaru hadn't ever made a 2.5 motor at this power level before, and they were overcompensating a bit; it's why the 04-06 motors tend to last a lot longer than the newer ones. My 05 was one of the very first at the dealer, and if I recall, the dealer was concerned with Subaru making little suspension/drivetrain changes (the wider rear track was a big one for them) over the 04 and not really explaining them very well to the techs. They didn't know if my motor was different at all to the 04s, and could only really guess... I mean, one werido tech was concerned with the sodium-filled valves, for goodness sake. So, with that said, they made me swear to bring it in for everything possible under warranty, and I was to watch oil consumption strictly at 3000 miles, keep track of how much oil I put in, etc. My Subie dealer also sold Porsche and VW, so I'm wondering if some flat-4 flat-6 experience in their shop didn't influence them in some way. I followed the rules, it drove me absolutely bonkers, but the dealer was very impressed with the lack of oil consumption compared to their other customers. I don't know if my car was unique, but I followed their orders specifically and it worked out well. After break-in, I ended up working with COBB on one of "their" very early downpipes (still branded with 'Stromung', lol) and was one of the first with a Stage 2 map. That car was a really cool ownership experience, and I miss it. I ended up selling about 3 years into ownership because I'd had 2 break-in attempts, and the "Dude-Bro" culture that now surrounds Subaru really bugged me.

tl;dr - I followed the owner's manual to a "T" and may have even gone a bit overboard. I should really look up that VIN to see if it's still out there somewhere.

Making sure you are up to operating temps before increasing revs is even more important on a new engine. The one thing the folks in the know at Honda always stressed was, not buying a new car and immediately going on a long drive at a constant, unchanging speed. It is wise to change up the type of driving you do on a new car. A bit around town, some out on the open road etc. All Hondas are redlined at the factory, so I wouldn't worry about treating them like a piece of china. I've driven hundreds of new Hondas over several decades, and treated none of them like priceless family heirlooms, but also did not go out of my way to abuse them just because I could.

Follow the factory procedures.

They're no doubt conservative and fail-safe but I naively trust the collective knowledge of the engineers who design and build these engines and cars over random guys on the Internet (like us) who deal in samples of one or two or even a dozen.

-- Chuck

Yup. There are more than a few Hondas (of all types) with mega-miles out there, as proof. Cars that had only dealer or mechanics following owner manual's maintenance guidelines.

:)

wow very cool experience, nice reading all of your info. I was wondering if WRX owners wave at eachother ? I thought that I heard that somewhere but maybe with the new models they stopped doing that ?