'02 OBW 2.5L coolant loss

Well, Job's Done!

Ultimately, it took me and my friend (an Aircraft Maintenance Engineer, ie airplane mechanic, LOL) 15 hours, 2 coffees (not counting morning doses), 3 Cokes and 8 beer. We started at 7pm Friday, worked to 10:30, then Saturday from 9:30 till 10:30 at night, with lunch breaks and the like.

We basically followed the sequence of operations in this post from the Outback forums:
http://www.subaruoutback.org/forums...der-head-gasket-replacement-2.html#post389816

I'd downloaded the factory service manual as well. Ain't the internet great!

This describes changing the head gaskets without removing the engine from the vehicle, we jacked the engine up by about 2", and used a rachet strap to pull it an inch or 2 side to side to access each side. The basic order of ops was:

remove induction plastic
remove windshield bottle
remove battery
remove bellypan
remove radfans
remove belts and tensioners
remove crank pulley (one of the few stumbling blocks, the pulley was stuck, but came loose eventually)
remove timing belt
undo engine mounts x 3
unbolt intake/exhaust mani's
jack engine
pull engine right
remove valve cover
remove head
pull engine left
remove valve cover
remove head
Reassembly reverse.

We learned alot about the car. The left head gasket had been changed before, but not the right. The right one failed. The right head's bolts were VERY tight, but we didn't need a snipe on the breaker bar, at least. Tight but not scary tight.
We took the heads to my friend's hangar, and cleaned 'em up with the varsol bin, plastic scrapers and finger nails. Straight-edging them against strong back light showed them to be as flat as the mark 1 eyeball could see. Subaru had previously advised that they have to plane less than 10% of the heads they take off, so we felt good about that.

We took about an hour cleaning surfaces on the block and nearby, with rags and sprays.

Torquing the heads is an odd thing on this car. THe recommended sequence is to torque 'em all in specified order to a medium torque (25ftlb approx), then tighter, to about 51ftlb, then detorque everything 360 degrees in 2 steps, then torque middle bolts to 22 ft lb, corners to 11 ft lb (in sequence), then 180 degrees on each bolt, 2 steps, in sequence. Took about half-an-hour to torque each head. At finish, they're VERY tight (squeaking/ticking), but not SCARY tight.

We also re-packed the timing belt idlers, as a short term measure. Their bearings felt smooth, but dry. It'll do for a while, till I feel like going back in. A timing belt job on this vehicle borders on easy.

So, by mid-afternoon, the heads were back on. At suppertime, it was down to the accessories and induction. Around 9:30, we were cranking the engine without plugs installed to push oil around. At 10, we had it idled up to temperature, burping the coolant system. A 15 minute test drive, and we loaded up the kids and went home.

Yesterday morning, the car took 2oz coolant in the rad. This morning, none. No coolant smell. No burning oil smell. Engine still looks clean.

It runs quieter.

Total cost: About $500, using all OEM parts from the dealership (whose prices were competative).

J

Well, I thought I'd post some photos... Not much to share, just a couple snaps on my friend's cell.

First, the engine disassembled, lifted, and pulled to the driver's side to access the right head. Both heads are removed in this shot:




Here's the failed head gasket, from the passenger's side. The gasket is obviously blown near my finger, all the black coating is gone. Interestingly, the other cylinder in that gasket had a failure too, right about at 7 o'clock. The gasket seems to be made of thin steel sheet, and one is rolled around another to make the "ring" around each cylinder. The steel cracked along that "fold", maybe 1/2" long. There was minor "washing" of the black coating near this crack.




Looking at the heads and cylinders, all the cylinders had normal carbon buildup in them, except the blown cylinder. It had been steamed clean by the leak. The blown cylinder also had a pink residue on the plug tip.

All 4 cylinders still have hone marks visible in the bores. Was a bit surprised to see that. Heartening.

It was pretty cool to see the engine's design in such depth. The head/valvetrain design is ingenious in its simplicity.

We were both pleasantly surprised on how easy it was to work on. We had to dig in deep, but there was always room for the next operation. I have a few friends with Subaru's. I'll be willing to help when (if?) theirs blows up.

J