New Car Break-in Question

I suggest the following: Warm up engine for 30 seconds or so before driving and drive easy till the temp gauge is up to normal. No more than very short periods of heavy throttle (5 seconds or so), I drive my Forester AT such that the transmission shifts at ~ 2,500 rpm. No long periods of steady speeds and no long idling periods like 15 minutes. Subaru says the first oil/filter change at 3,000 miles and NOT before 1,000 miles so I split the difference and changed at ~

Assuming no abuse of the engine, I don't know that there is much you can do to affect the longevity of the engine based on how you drive it during the so called break in. The point of "break-in" is to wear the piston rings such that they seal well.

In the motorcycle world, a rebuilt engine is typically worn in by WOT (wide open throttle) acceleration to redline and then shut down to cause the resulting vacuum to draw more oil to the cylinder walls and lubricate and cool the rings. I've done that with my Bonneville, Forester, two Caravans, and some other cars and typicaly have zero oil consumption. My Taurus at nearly 200,000 miles used a quart in

I'm not recommending this method, but present it as an example.

Is that new?

That recommendation wasn't in the '01 2.5 manual. How do you hurt a modern engine by replacing the oil (not with synthetics! ) @ 1k?

My '01 OBW did a 2000 mile highway trip at 1300 miles on the odo, with no ill effects.

As far as breaking it in, I'd simply drive reasonably after 1000 miles. 1000 miles is a few revolutions on the ol' crankshaft, and the pistons should seat by then. You should check your oil at every fill-up during the early life of the car, as they can use more oil before the rings are seated.

I normally switch my cars to synthetic oils @ 5k.

Enjoy your trip, and don't worry about it.

Hi,

Ed, I'm really talking off the top of my head here, but didn't someone post something a few months ago about some kind of break-in agent (I'm thinking moly at first) that Subaru puts in the factory oil fill?

IIRC, the idea of a dedicated "break-in" oil like mfrs used decades ago was dismissed, but it seems someone had info on an additive that was supposed to be given some time to work. I could be all wrong, though. ???

Rick

Seems like there's always SOME question about breaking in! lol! Yeah, I think some analysis of oils from the factory folks have sent in for used oil analysis have found elevated moly - but then there's the speculation it is from special lubes used assembly. It is also frequently pointed out that a few cars come from the factory with synth already in the crankcase. Dunno if those vehicle get special treatment to the rings/cyls though. Then there's the guys that recommend heavily loading the engine to increase pressure on the rings to force the 'wearing in' to go more quickly and avoid 'burnishing' the hone pattern.

I dunno. I drained the factory oil at 1300 miles and now use Mobil 1.

Carl

Rick Courtright wrote:

Current thinking is don't waste your time. Modern engines are built to accurate tolerances and bench run before installation. Purpose of taking it easy for the first few hundred miles is just in case there are any installation faults. No reason why you can't start thrashing it now. Subarus are particularly tight and you won't get full performance until it has loosened up quite a lot, so the sooner you start that process the better. Get your 1000 mile inspection and oil change done before you set off on your long journey and don't skimp on the oil. Go for a top-end synthetic.

David Betts snipped-for-privacy@motorsport.org.uk

You'd think that would be mentioned in the manual.

That will be what it says in the handbook, yes. They are covering themselves. Three or four hundred miles is plenty. Then start upping the revs a bit. It actually takes about 20,000 miles of hard driving to get one of these engines nicely run in and performing at its peak.

David Betts snipped-for-privacy@motorsport.org.uk