3p141592654

I don't see any tribological data here. Only idealized hydrodynamic type data. Also - instantaneous is different than integrated, and higher rpm would bring with it increased temperature, etc. - it's not a simple system.

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Indeed it is not simple. These simulations were done using AVL\Excite software and the elasto-hydrodynamic method. The bearings under study are from a turbo diesel and the study was focused on modeling wear from oil cavitation. Its a published SAE paper if you want to read more about it.

... now back to software shifts. Speaking of which, it is true that holding at peak HP is best for acceleration, but dithering +/- 1000 rpm of 4100 rpm peak probably won't have much affect since my seat of the pants says the horsepower peak is pretty broad on these engines. I cannot find a dyno plot for the FB25 anywhere to confirm.

The truth is that car engines almost never wear out. They suffer either a catastrophic cooling or lubrication event (low coolant, low oil, excessive oil drain intervals, sludge buildup, detonation) or they have a metallurgy/gasket failure from too many thermal cycles.

If inertial forces were the largest then the aftermarket forged rod and piston people would be out of business. Stock internals can run at red line forever but increase the horsepower of an engine and they eventually break. Why, because the power stroke force overwhelms the rods and pistons. The inertial forces haven't changed.

Here's a FEM analysis of bearing load as a function of crank angle? I'll dispute your claim of inertial loads being the biggest.

Our 2005 Outback had a coolant leak at one point, couldn't find it but I could smell it. It was dripping on exhaust so burned off and only leaked when running, Quite annoying, until I repaired it.

Agreed, the smell suggests external leak, but it still could be from a crack in some component or a bad gasket. I have a 4 gas analyzer so I plan to sniff the rad with the cap off to see if there is any evidence of combustion gases.

What was the source of your leak?

Explain. It is generally considered that long-term engine wear is directly correlated with total crankshaft revolutions. Higher RPM => More crankshaft revolutions per mile traveled.

Actually not true. Peak bearing pressure and thinnest oil film occurs during the peak cylinder pressure on the power stroke and is worse (thinner) at low rpms. So the highest and most damaging loads occur at high bearing pressure and slow rpm, which is why lugging was discouraged in older times. These days you can model the film thickness under various conditions and design the bearing to handle it, but it is categorically not true that bearing wear is just a function of crankshaft revolutions, it is not that simple. If you can ensure a minimum oil film thickness then operating wear is negligible. For ring wear, I would agree with your comment.

This plot may help with understanding.

If its steadily dropping with mileage there is a leak. And my nose agrees. But I'm documentating this carefully and will do my own pressure test to see what I find.

I'm well aware of coolant drop on a refill, and I would expect things to level out after at most 2 or 3 drive cycles.

A liter is quite a bit, but I would keep an eye on it while you're under warranty.

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If you aren't content with watching and waiting(not sure hold long you have until your warranty is up), then I would definitely recommend contacting Subaru of America directly by phone. The customer service I received when I needed to call about the dealer not replacing my head unit at warranty was phenomenal. If you are by another dealership, I would try that too, as some dealerships are just better than others in terms of service.

Dealer has had the car twice for this problem. First time was at 6000 mile oil change and I noticed the reservoir was dry. Figured maybe it was not filled from the factory as I never checked on delivery. The dealer filled to full.

About 2000 miles later I noticed it was at half when cold. Brought it in for just this issue and they called after 2 hours later and said NPF. Gave me a story about how the level varies with temperature. Yeah really, that's why I gave them a photograph of the reservoir when the car was cold!

Anyway, I said keep it overnight and do a pressure test. The next morning NPF. They didn't say whether it held pressure or not.

I can smell coolant on the passenger side of the engine bay with car hot and in the garage . But I've looked and can't see any signs of a leak. Makes me think this could be a cracked component inside or even a BHG.

My current plan is to photograph the cold reservoir every 2 weeks as it steadily drops. I'll put together a nice PowerPoint and then have a talk with the dealer. If that goes nowhere then I'll call corporate as you suggest. I've already got two service logs with the problem, so I figure I am covered warranty wise, but this car is new and there's lots of warranty left.