DaveT

Oh, change one, change both. Same miles, same time.

Same oil doesn't surprise me. I use Amsoil synthetic in everything. Go by the Subaru owners book. Amsoil has reference application guides also.

I doubt it.

Try using the view as desktop option?

I'm thinking it's older ones. I think I remember my 76 and 78 wagons having a screw. GLs and Loyales that I have are D shaft push on. I never had a screw fall out.

+1 what GD wrote.

Hose size is determined by airflow required by the tool. And length of run if it's unusually long. Fittings should match hose size.

The cts an fail in a lot of ways that won't cause a code, but screw up drivability and or idle and or starting.

IAC shouldn't have any effect once you are significantly off idle, and open throttle. The effect of its relatively small area vs the main throttle would be swamped.

Sounds like a choke problem

The aftermarket ones have smaller valves. Probably restricting flow more than stock ones. The cooling system is the weak link in these cars, so I don't mess around. Oem or high end Stant only.

I had a 76 like that one, except only 2 headlights. And a 78 that was blue. 2 of the simplest and most reliable cars ever owned. Your noises are probably the cv shaft. That old out there, might need seals for the wheel bearings. The bearings are standard ball bearings, any industrial bearing supply place will have them if car parts places don't carry them.

Cts can screw with things for certain. When they go bad, the effects are pretty similar to a choke problem on a carburetor engine.

The black stuff takes months to build up. And getting one to run for months with the beginning failure takes very close monitoring of the coolant level. Like checking before every drive. 99 % of my experience is on the older ea82s. It Takes a good few days of close monitoring to determine for sure if it's the headgaskets pushing the coolant onto the recovery tank. A recent thread seems to have semonstrated that a bad radiator cap can cause similar symptoms on some models. There are other similar threads with the details.

Low coolant in radiator is bad. Excess coolant in overflow is bad. Cheap aftermarket thermostat is not good. Failing headgaskets typically do NOT mix coolant into the oil on subarus unless they are very fully blown. If run for a long while with the beginning failure, the continual slow leak of exhaust gasses will leave traces of black stuff in the overflow tank.

To find a battery drain. Unhook the negative cable. Connect a test lamp between the battery terminal and the cable end. Pull fuses until lamp goes out. Also the thick white wire on the bolt on the back of the alternator.

If the 24 is for the Idle Air Control valve, that can kill idle. Check that it clicks if you apply 12V to the coil. Check the lamp for the CEL. It should light during crank / or key on engine off, just like all the other ones light up. After installing timing belts, I turn the engine a couple of revolutions. RE check tension. If it's still ok, run it for 10 seconds - before installing anything else. Then re check. Sometimes, the belts are not in their normal running path when you first install them, this gives them a chance to settle into position.

There are numerous threads about setting up the timing. The factory service manual is also good. Miles Fox youtube videos I have heard of also.

Typical alternator failure

Both sides of a good fuse should be same brightness, usually full brightness with a test light. Lots of people report trouble with aftermarket alternators. O2 sensor doesn't do anything until the engine is up to normal operating temperature. I don't know xt6s, just spfi ea82. Double check harness connectors that were unplugged during the reseal.

Cvs pop when turning, bad. Try to find oem and regrease and reboot. After market are junk. Ac. The only way to find out what's wrong is to recharge it. Put a dye shot in it also. R12 was original.

yes, the glass method. You need some way to press the valve springs down, to free the keepers. I've done it by using a piece of bar with a hole in the middle, and pressing legs on it, on the floor, as you need hands free to deal with the keepers. The last time, I used some unistrut to make a lever with a hing, clamped to the workbench, so I could hold it down with one hand, and handle the keepers with he other. I used a piece of foam or rag underneath to make a support so the valve didn't just open, which makes it impossible to remove the keepers.

Definitely resurface the heads, otherwise new head gaskets fail. Find that thread, it isn't difficult or expensive. I clean the valves of they have carbon build up, one at a time as I do the seals. I have lapped them sometimes also. Have not needed new seats or any other related parts.

There are lots of threads with good information. One in particular is about post apocalyptic head resurfacing.

Oh, also, you will get more replies in the newer generation sub forum