Scoobaroo

Thanks, everyone. I'll change it soon. Shouldn't take me more than an afternoon and a six pack. (I have impact wrenches, too.) Are the E-Bay idler/belt kits any good? My gut tells me to go with an OEM belt and an OEM water pump. My point was that Phase II 2.5's aren't really known for belt failures. I suspect that 105k is a bit conservative on the interval. Anybody want to see pics of the job or are there enough pictorials on the site already?

2002 OBW 2.5 AT- 107k- Original T-Belt. Original owners. I know it's due @ 105k. Took a "peek" behind the t-belt cover. The t-belt looks new. I know what a good timing belt looks like and this one looks good. The tension is good. No glaze or cracks. I have the experience to change it and the water pump/idlers in probably 4 hours, but I'm a cheap, lazy bastid. My impression is that OEM Subaru t-belts are really high quality and might go 200k miles in this SOHC application. The water pump doesn't leak. The engine doesn't leak a drop of oil. My question is: has anyone ever had a 2.5 (SOHC) T-belt fail before 200k? I know its an interference design and the valves/pistons would be toast if the thing fails, but this belt doesn't even look close to being worn out and I don't hear of many (or any) SOHC 2.5 belt failures.

Nice pics. Many people don't understand that the crankshaft bolt needs to be tightened to 150 ft. lbs MINIMUM after working on the front of the engine. 200 ft. lbs is better IMO since factory tightened stuff on Japaneese vehicles seems WAY overtorqued anyhow.

A normally aspirated engine will lose around 3% H.P for each 1,000 ft rise in elevation. At 4,000+ feet, you're down about 12% compared to sea level.

This is a non-issue on Subie engines. The filter is mounted upside-down. It may siphon out once in a while, but even an anti-drainback valve won't prevent this. I still avoid Fram like the plague, though. Cardboard and glue construction. No thanks...........

Are you talking about a $100 deductable or paying 1/3 of the total cost? $100 is 1/3 of $300. Replacing 2 pistons is more like a $1200 job at least.

You're a person after my own heart! Assuming you just want a "freshen up" and there are no major problems with burnt seats and/or valves: Mark the valves so that they can be returned to their original locations. With a wire wheel, clean the carbon from the front and rear of the valves. Put some fine grinding paste on the contact area of the valves and seats. Insert the valve into its guide and chuck the valve stem into a cordless drill from the top. Spin the drill at slow speed and pull upwards slightly on the drill to apply pressure on the seat area. Stop when you have a nice contact finish on the valve and seat. Test the seal with some kerosene or other thin liquid pooled in the combustion chamber with the valve springs installed and the heads upside down. The valves should hold the kerosene for quite a while. There shouldn't be much noticeable looseness with the valves fully inserted into the guides. If the guides are worn, note the installed height and drive the old ones out. Freeze the new ones in the freezer. Heat the head to 400 degrees in the oven. The freezing cold guides should almost fall into the hot head with just a few taps of the proper sized socket. Valve seals? You know what to do...........Pliers for removal, socket and hammer to tap them on.

Did you have an analysis done? I'd be interested in seeing the numbers if you did. The "SM" standard is very tough to meet. I run 5k intervals with ST 5w30 in '02 Outback with a SuperTech filter. No problems so far. Do you do a lot of short trips? Short trips will tear up engine oil pretty fast. Some used oil analysis of Supertech that I've seen have been no better or worse than any other oil.

SuperTech oil is the nectaur of the Gods............and for only around a buck a quart. Toss in a SuperTech oil filter and you have around an $8 driveway oil change. White trash livin' at its finest! Don't forget to recycle that old oil!

Since the problem isn't the oil, oil shouldn't be expected to quiet the slap. Dino, synthetic, straight weight, multi weight, thick, thin. Knock yourself out. Try them all. Won't make much difference if any. The 2.5 is a woodpecker engine. Short piston skirts and loose clearances. Seems to be oil temperature related, not coolant temperature related. Our Outback makes the noise even after the temp gauge is in the normal range. Shortly after that, when the oil temperature stabilizes, the piston slap stops.

Even if the belts were changed, they're almost due again anyway by mileage. Change them.

You can wash with water all you want. I won't help much. Salt and Mag Chloride wick their way into all of the microscopic body seams and start the rust process. The only thing that helps is to use something that ALSO wicks into the seams to stop oxygen contact with bare metal. In Canada and Europe, used engine oil is sprayed onto and into car bodies. I've bored out the end of an old paint spray gun and have absolutely saturated the underside of old cars that I've owned with used oil. In time, the old oil drys to a sticky film that actually holds up well and freezes rust in suspended animation. Try to be as environmentally responsible as possible in doing this. I used to use old cardboard to catch the drips, then burned the cardboard. This was better than letting it soak into the ground, I guessed. This was when I lived in New Jersey. Rust problems aren't as bad here in the west.

In your original post you said it made the noise hot and cold. If it makes sort of a "tock"-"tock" noise cold that diminishes as the engine warms up, that's classic Subaru piston slap. The dealer will feed you the "normal" B.S. line. Replacement pistons will get you out of the warranty period, but they will eventually slap as well. There is always the risk of an untrained monkey opening up the innards of your engine, too. Most of us just live with our original, slapping pistons. My '02 Outback slaps the least on cheap-azzed Walmart 5w30 oil.

A compression test and leakdown test isn't really an oil ring test; it's a compression ring test. My bet is that the oil control rings are either stuck or worn. There's no way that a quart per 150 miles is getting past the valve seals. Excess oil on the cylinder walls due to bad oil rings would actually INCREASE your compression readings and reduce leakdown on a static level. Even an engine with no valve seals at all wouldn't burn that much. I see an engine overhaul / replacement in your future.

Guys, he said that it started acting up immediately after his mechanic cleaned the throttle body. There is a 99.9% chance that the guy who serviced the throttle body f'ed something up or adjusted something that he shouldn't have. Only one thing really changes the throttle body from it's factory perfect condition; a small ridge of gunk/carbon buildup in the area where the throttle plate comes to rest close to the inside bore of the body itself. This clearance without a buildup of carbon is critical for proper "minimum air rate" past the closed throttle plate at idle. A few thousanths of an inch of carbon will begin to affect idle performance. Take this for what it's worth, but never spray any cleaner into the throttle body. Never adjust any screws on the throttle body. If you can open the throttle plate and feel a tiny ridge of carbon where the throttle plate comes to rest, simply rub it away with a clean, dry cloth wrapped around your forefinger. That's all you need to do. The adjustments to the throttle body are sensitive down to a few 1/1000ths of and inch. The throttle position sensor can be damaged by cleaners. The IAC motor is also sensitive to cleaners. Your "mechanic" may have also left a vacuum hose off somewhere.

I'm talking about the little ridge of carbon that builds up over time where the throttle butterfly seats, not the coating on the aluminum itself. This carbon deposit will affect the minimum air rate somewhat. Stay away form spray cleaners. Just wipe the inside of the body clean with a dry cloth. It's not really a big deal. Dealers SAY that it's a big deal so that they can charge you a hundred bucks to do it.:-\

With the rubber air intake boot removed, manually open the throttle butterfly and feel the area around where the butterfly comes to rest for a small ridge of gunk. If there is a small ridge of gunk, manually rub it away with a rag wrapped around your finger until it's gone. Using spray cleaners is a bad idea. They can wick themselves into the Throttle Position Sensor, the IAC motor and dissolve the internal throttle body coating. DO NOT mess around with the screws. They are factory preset. Cleaning the ridge of carbon away should restore the throttle body to proper operation. Dealerships love to hype up throttle body cleaning. They charge $100+ for 5 minutes worth of work.:-\

Regardless of displacement, an NA engine will produce around 3% less HP for every 1000 ft. rise in elevation from seal level. Fuel injected engines can compensate somewhat by leaning the fuel mixture and advancing ignition timing, but the HP loss is due to a loss in real barometric pressure ( the amount of natural air pressure waiting on the opposite side of the throttle plate.) and air density. There is a curve to the HP loss. under 4,000 ft. or so, the loss may not even be noticable (seat of the pants) once the computer has compensated for the lower air density. At 10,000+ ft, the loss in air density becomes exponentially greater. At thest elevations, you've most likely lost around 35-40% of HP. Air temperature and humidity are factors also.

Walmart Supertech 5w30 and a Supertech filter every 5k miles. No problems. You can't beat a $6 oil and filter change. SL/SM oil is SL/SM oil. They're all the same within about 1%. Paying more simply fattens the wallets of CEO's and pays for magazine and TV ads.

With 82k miles, the O2 sensor(s) are probably lazy. They practically have to be flatline dead before they'll set a code. I read somewhere that they really only operate at peak performance for around 30k miles. You need a scan tool with data stream monitoring in order to view their performance in real time. Their voltage should fluctuate fairly rapidly between .2 and .9 volts, I think. Most volt meters aren't suitable for reading rapid fluctuations in O2 sensor voltage.

Not trying to steal the thread, but what is CCR doing to eliminate piston slap? Select fit pistons? Coatings? Emily?

Yes.

Agreed. The moly coating is only there to sell the car since nobody would buy a piston slappin' car brand new off of the lot. The rocking motion does increase some because the moly coating is a few thousanths of an inch thick. When it scuffs off, the piston skirt is smaller by a few thousanths. The increased rocking motion scuffs even more material from the skirts until your 3 year old Subaru has the piston-to-bore clearance of a 40 year old Mexican school bus. Car companies are good at covering their f-ups with slick sounding TSB's. ".........the knocking sound is a characteristic of a low friction engine design............the noise won't affect engine performance or longevity........."(blah, blah, blah.) (Translation) it would cost us a $hi%load of money to deal with the head gasket and piston slap issues. Let's add a bottle of sealer and print a 3 cent piece of paper telling people that the slap is "normal".

This piston slap thing is a "Cluster F.....". When these engines are new, the piston-to-bore clearance is around 2 thousanths of an inch or so and all is well (and quiet.) The problem is that 2 thousanths of an inch quickly becomes 4,5,or 6 thousanths of an inch clearance due piston skirt scuffing. There is no way that a piston with skirts as short as the 2.5 has can ride squarely in the cylinder with 5+ thousanths clearance.........ain't gonna happen. On the other hand...........fitting brand new pistons tighter at the factory could lead to piston seizure. (Not an option). Due to the bore and stroke measurements of the 2.5, it's almost impossible to engineer a piston with skirts longer than the present ones. (Also not an option). You could change your oil every day and it wouldn't help. In a nutshell, a 2.5 almost can't have quiet pistons for more than 20k or 30k miles if you live in a cold climate. Your new short block will have "the slap" again in 30k miles.

As a side note, much of the stuff on BITOG is worthless. His oil filter "flow tests" are performed with room temperature oil. An oil filter will bypass room temterature oil, not filter it. His oil filter cutaways are interesting, though. Yes, the 4 ball test is next to worthless with regard to engine oil. Also, it's been proven that contaminants smaller than 20 microns will stay suspended in oil and cause no engine damage. Therefore, it's useless to obsess and overspend on an oil filter that filters particles down to, say, 10 microns or 1 micron for God's sake.