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There's only one high pressure oil passage on the top of the gasket. If it's flipped backwards that would explain the leak. It's the topmost oval one. It should match to the top port

You mentioned you're doing it in car right? At this point, might as well remove the radiator to get the best possible outcome for tapping a hole... especially if it might break through into block.

I don't know if there's a definitive procedure for creaking bolts. I could tell the if a creaking bolt has gone beyond it's yield, it just feels springy when you tighten. A good bolt can creak too, it's sometimes due to the threads in the block not matching the threads on the bolt. Good bolts that creak still feel as stiff as ones the didnt creak. I run them in and out a couple times lightly with a drill and clean/relube the threads. then try again. Be aware MLS gaskets deform as part of sealing, and then bite a bit into the aluminum at final torque. You shouldn't loosen the bolts all the way once you started, if you need to work on a problem bolt, back off the other bolts as little as you need to and always leave them in tension. At the torque wrench stage, try and keep everything creak free. Keep cleaning and relubing if needed. After that is the 1st 90 degree stage, some likely creak, you need to remember the feel of the good bolts and decide. It's the last chance to back off and redo. The second and final 90 deg stage, if it's a bad bolt you will definitely feel it. Never go more than 180deg total for those two stages, if it felt loose after the two stages... it's overstretched already.

It's not recommended to reuse headbolts, but I've reused headbolts before. You'll know you have a bad one when you do the final torque and it squeaks too much or just doesn't feel tight. I have a bunch of used ones laying around so it's not a big deal. It might be a show stopper if you don't have spares on hand.

Any silicate free coolant is fine. Subaru coolant conditioner was a rebranded stop leak to keep the composite gasket from flaking off. Subaru MLS shouldn't need any conditioners.

i find a table, bench, any flat corner with a L and taller than the entire axle. hold axle vertically into the corner with outer cv facing up; slam it down hard so the outer cv catches in the corner L. it's like a reverse slide hammer, mind your toes.

Angle looks bad. Get some more washers on the upper bolt to space it back in line. you might need a longer upper bolt. I did something like this when I still had the narrow wagon swaybar with the wider sedan control arms.

Does it start going christmas lights only after you start the engine? If so it's likely a broken alternator regulator sending ac voltage in the system. Try unhooking the red charge wire on top of the alternator and starting the car.

I'm installing TGV sensors again and forgot the twisting procedure.... Was it always install it with the connectors facing up and then twisting it into place for both sides?

You just need to jumper the clutch switch that goes off on full depress. The clutch switch on slight press is the one that disengages cruise control, doesn't have anything to do with the starter. FYI

did you go from nonturbo to turbo? the p0420 is pretty tricky to catch even on the original car. even throwing on a different exhaust system could trigger it. don't try and chase the problem itself, but get other things dialed in and worry about p0420 last. the car will run fine with p0420 code and no other codes, at least anything before 2007. it just won't pass smog. with that, some things to check if you haven't done so already: your mass air flow sensor is probably okay. make sure the car runs strong in closed loop, no misfires or rough idling. part throttle should be smooth, put it in 1st and see if it can creep along smoothly in idle. creep along smoothly 1000-1500rpm. try 2nd gear if it's bucking or missing, then check your maf sensor, intake, vacuum leaks... on the exhaust side of things, make sure the entire path from engine to the rear cat has no leaks. the flex joint and gaskets just before and after the cat are usual suspects. test with whatever way you think will help, i don't know of any surefire way for me, i had one car that would pop a p0420 every couple months, even did pressure smoke testing and never found the anything. only by chance one year i decided to sand a rusty looking flange only to find that it was slightly bent, the other mating flange was bent in the same direction so everything mated up and sealed fine, but was C shaped ever so slightly, you can't even tell by eye. after getting everything flat again, the problem went away for good. still on original cat from 2002

I've never seen a solid sprocket like that before. All the subaru ones of that era look like the one in the first post you made. Clearance should be about 1-2 business card between sprocket and sensor. You timing looks good enough though.

Is the EJ251 like the old EJ22 sohc with only a single cam sensor? If so, I've had an EJ22 skip many teeth on the non-sensor side and not throw any code. Engine ran really rough on idle. The flashing cruise is an immediate misfire signal and doesn't set any code. I'd check timing again with just two covers removed.

next time you catch it happening, open the reservoir and shine a light in, have someone steer the wheel with engine on. if you see bubbles it's a hose leak.

Definitely disconnect the battery. Also I've had a wrench fall between the positive terminal and an ac line. After the sparks stopped there was a nice hole in the tube. Now I prefer pulling the negative side and leaving the positive terminal covered.

Be careful adjusting the hydraulic clutch pedal. The master cylinder rod needs to fully release when the clutch is all the way up. There's a tiny hole in the master piston that releases pressure when it's all the way released. This is to account for temperature changes and expansion. When the clutch pedal is fully up, there should be some play in the pin connecting the pedal to the master cyl rod. There's a spring in the slave cylinder that takes up the slack. There's no pretensioning to adjust over time like cable clutches, the spring in the slave cyl self adjusts after every press and release. It sounds like either there's air in the system from a bad slave seal or the hose is rotting out. Also could be cracked clutch fork.

Used to always clean out and replace the factory bearing grease whenever I install new ones. I've noticed they come in sealed plastic pouches and already greased. Is this already wheel bearing grease and ready to install? I'm getting older and lazier these days. This is for NTN or Koyo press in bearings on earlier subarus.

The radiator endtank is plastic, gets brittle and cracks easily, even when leaning over the engine bay and you inadvertently put your weight on it. The hose is likely fused to the nipple, cut it and peel away if needed. Also don't go overboard tightening the hose clamp on the radiator end.

I've recently noticed this with a bad tensioner; the side with the two smooth idlers, you could grab the top belt with your fingers and bottom belt with your thumbs and squeeze by hand. I had a failing tensioner and was able to see it move way too freely when squeezing. I've not tried this on an engine with a good tensioner, but pretty sure you wouldn't be able to move it with just hand strength.

Great writeup mpower! Those pictures really show the issue at hand.

I'm rebuilding a 2004ish era EJ DOHC. I'm wondering if a stretch belt for the AC from a newer gen would fit. Has anyone tried this before? Was it worth the swap or just more hassle to install/remove?

For a '96, it probably needs a new upper radiator hose. Squeeze the hose with your hand, if you hear crunchy sounds it's time for a replacement.

That kit doesn't have seals included, new bearings won't last long if water and dirt get in. Get new seals to go with your model, fronts and rears are different sizes so pick appropriately. The video is for a newer subaru with integrated bearing and hub unit. Your 2002 is a lot more involved, the bearings would need a press to remove and install. There are snap ring and seals to contend with.

I'd worry less about silica and more if there are flakes in the oil. Silica can be remedied: better filter or shorter intervals between changes.

Yup dohc cam plugs https://parts.subaru.com/p/Subaru_2004_STI-25L-TURBO-6MT-4WD-SEDAN/Engine-Camshaft-Plug/49223411/11051AA070.html