jonathan909

A little story, if I may. When I bought our first Subaru seven or so years ago, I knew it was overheating and that I'd be jumping into a head gasket job right away. So I started asking questions (on another forum) and found a lot of help, including the same admonition to stick with the OEM thermostat. I asked why, and to the forum's credit I got useful technical answers about its hysteresis characteristics and aperture size - stuff engineer-type geeks like. So I headed on down to the dealer and told the parts jockey that I needed a thermostat. He said "Be right back" and immediately turned to fetch it. I tried to stop him - after all, I hadn't told him which model, year, engine, or temperature I wanted. He replied "We only have one." That was the moment I decided I liked Subarus - a lot.

Okay, then no downside to having one on a motor with an AT.

So why not just always have it there? Why in one case and not the other?

I don't understand. It's just a guard that doesn't contact anything.

I've been meaning to ask about this. Why one and not the other?

Both EJ25S (SOHC), right? If so, yes, but when you do these swaps you generally just trade blocks and keep the intake manifold with the car. That way you avoid any sensor disparities. Oh - does this one mean a change of cam sprocket?

Of course - the difference in both quality and price between OEM and "the aftermarket" is a given. What I was saying is that massive price disparities exist among parts of equivalent OEM quality - that in the stated example, going to the dealer means paying three times as much for the same Mitsuboshi belt. That's all. Not recommending anyone "cheap out"; to the contrary, pointing out that the high-quality/low-price combination exists, so don't get taken. Myself, I like Terry Pratchett's version of that old adage: Make a man a fire, and he'll be warm for a day. Set a man on fire and he'll be warm for the rest of his life.

We don't have to get contentious - what you're calling "a treatise" I'd call "a proffered opinion". We do this because the OP may not be aware that such a huge disparity in parts pricing exists, and thus may not know to ask.

Guys, it's always easy to say OEM/dealer, but for an awful lot of stuff it's simply not realistic. There are two dealers here. They quoted me $170 (CDN) for an EJ25D belt - and at that price I would still have had to wait for it to come in from Portland (i.e. no local stock). Instead I landed a Mitsuboshi from an ebay vendor for about a third of that price.

Gotcha. All mine are D. Is it just the 251s that have the valve reliefs, or does that apply to the later pistons (252-255, etc.) as well?

That sounds like a perfectly terrible answer - I despise electrical tape at the best of times, and in this case it's guaranteed to get trashed and spread its disgusting gooey adhesive all over the damn place. But it might be a good diagnostic for a worn latch mechanism.

I have absolutely no idea what pistons these are. I think I asked previously (like before I installed them during the rebuild) how to ID them but didn't get an answer. And it's not as simple as what shipped with a '99 EJ25D, as the original short block was trashed (spun bearings) and I bought a used replacement that (I think) is "somewhat newer". So, assuming I can recall enough detail about them, how can I tell what they are? How many variants are there?

The worst would be a cracked block, but that doesn't seem likely. I'd be getting that timing cover off of there asafp to confirm the water pump.

This isn't a light-and-tinny plate rattle - it's a got-some-mass door rattle. It manifests with normal road vibration; when I wiggle it by hand it seems like there's the play that would cause it. What's left other than the gasket (which seems to be in pretty good shape) and those little springy-things? The latch itself? Do they wear?

Possible but unlikely - I put a new belt and toothed idler in but re-used the tensioner, since it appeared to be okay. But I'll probably pop the cover off and revisit it to make sure. I'd still like the knurling questions answered, though.

This has been drivng me nuts. I replaced those two little springy-things with what seemed light a tighter pair, and the rattle persists. What's the fix? New gasket or something else?

I can't be the only person who finds this weird. Now that my (rebuilt stock) EJ25D is back in the '99 OBW I've been noticing a bit of (what must be) slap, and it's unpleasant. I think if I'd thought a little further ahead and anticipated this rather than being hell-bent for finishing the job after all the delays, I would have had the pistons knurled. I'm pretty certain I'll have it done as a matter of routine in the future. So can you give me a ballpark cost for knurling a set, and is there any downside to doing it?

Oh - so you had a skip and not a crash? Then my $.25 is to spend a few bucks on it. I jam econo too, so I just replaced the belt and the toothed idler (which, for some reason has a much higher failure rate than the smooth ones), but went premium on both (per GD's recommendation): Mitsuboshi belt and NSK idler - I think I paid less than $100 CDN for the pair. Unless you have a reason to distrust the pumps and tensioner, that should do it.

A very slight taper right at the tip (which is flat so it can tap all the way to the bottom of the hole, unlike the usual pointy tapered taps) just to get it started.

It's just an aluminum casting - shouldn't be that hard to tap - but you're going to have to use a bottom tap, otherwise a through-hole tap taper is probably going to just chew up the hole.

Just to clarify, a helicoil is a coil of square wire. You oversize drill and tap the damaged hole, then screw the helicoil into the new threads - that's what keeps it in place. Then the inside of the coil is the new thread your fastener screws into.

"Awful sound" doesn't give us a lot to work with, but let's give it a go. The most common cause of misfires is bad spark. So take a look at the plugs - these engines strongly prefer NGK. If they're something else (or just ugly), replace them. Look for carbon tracking on the outside of the plug ceramic that suggests you've been losing spark to the outside of the plug. Check that your wires and connectors look/feel good. Listen for arcing where the wires pass by metal. If that doesn't solve it, the next step is a compression test to see whether the engine internals have a problem e.g. a broken valve.

Mobsters planted bomb. Get out.

Yikes. Get the exact wiring diagram for your year and model.

Nothing "hard" about it. First head gasket job I did was on a '99 OBW w/ 2.5, and I did it without lifting the engine at all, which made it a bit more of a challenge than otherwise. Lifting engine a few inches (too lazy, ornery, and rushing to beat the cold weather to unbolt it from the tranny) would have made it a little easier - when it's that tight to the wheel wells every 1/4" extra knuckle room makes a huge difference. But by the time you've stripped all the stuff off necessary to remove the heads, you're only half a dozen nuts+bolts away from having the motor unhitched anyway, so you might as well pull it. I've had the engine in+out of my '95 (same as yours) a few times and it's a breeze. The real problem you have is how much it was overheated. If you get on top of it early enough and keep the engine temp under control, you may be okay with just the gaskets. But if it's been severely overheated you may do the head gaskets only to have the crank bearings fail shortly thereafter.