DaveT

Heater core blocked or air pocket in the water pump. Either one will interfere with normal operation of the thermostat / cooling system working. Probably worth testing the heater core and radiator for flow. WATER should move through them very freely.

radiator doesn't owe you anything either, if it's original.

Now that it's been over temperature a few times while low on coolant, yes, likely needs headgaskets. The brown water, well something has been wrong or neglected for a long while.

+1 check timing belts.

I had the p0420. 01 forester. SMALL hole in cat pipe was the cause. Didn't make noticeable noise. A bracket had broken, and the end rubbed a hole through the pipe.

Always resurface is what I have done, and seen /read. You want to get rid of the impressions of the old fire rings.

If it's rust free, and otherwise decent shape. If the headgaskets are original, they usually need to be redone anyway, due to oil leaks. Needing a water pump may or may not indicate that it's been overheated. Has it been run over normal temperature while low on coolant? That has been the sure way to kill headgaskets in my experience.

It would be the first thing I would try to trace out. I have never run a car with a digital dash, so I don't know what the fail looks like. When I can't get a schematic of something, I just start drawing out the schematic from the actual circuit. As long as it isn't potted, or using custom ICs, it is just patient / puzzle. Then redraw so it makes sense.

The majority of clock failures is due to the choice of main power regulator. THE clock circuit runs on 5v. THE 3 most practical ways to get 5v from 12 are switching regulator, pass transistor regulator, zener regulator. These are listed by order , highest to lowest. Cost, efficiency, complexity. They chose the cheapest simplest and least efficient one. SO it has to cook away a watt or 2 of heat. In a small enclosed box. THAT is installed in a closed space, dashboard, where the ambient temperature can get over 140 degrees. The resistor that drops most of the voltage as waste heat gets so hot that it causes the solder on its leads to corrode and the connections fail. A linear pass transistor regulator would have to dissipate roughly half the power that the zener regulator does. Even back then, those were cheap and common. Side note, a switcher was not a financially practical choice back then. There is one other feature of the clock design that can be improved also. BY adding a diode and capacitor to the keep alive power feed, the clock doesn't forget the time when starting the car like it did a few times per year, before I added them. They actually had no filter on that line to smooth over momentary voltage dips.

Sounds like the heads you have are not a drop in. Find a good head that matches the one missing a valve. Or replace and lap the valves. Machine the Headgasket surface.

Put a real voltmeter on the battery, what is it reading? Probes right on the terminals. That is how to check for more clarity. If the voltage apparently changes by adding more loads while driving a steady speed, the regulator may not be working. Overcharge like that will hurt the battery. Gas here has ethanol, iirc 10%. NEVER had a problem with it, but I'm running EA82 engines. Get some water in there, and you have trouble , yes.

Above is a trace from my 87 Above is a trace from my 93 I also let air in via the feed to the HVAC controls storage tank. The effect was that the trace drops to the low level, following the curves similar to the drops in the normal traces above. After a bit, the trace would begin to move up again, looking like the ECU started compensating. Similar happened in reverse when I injected propane. For that, I added a T into where the feed hose picks off for the IAC valve. Capped when not using. Dialing the propane on / off would do what you would expect. Propane makes the trace go high, then after a bit, the ECU starts to compensate. Turning off, trace drops to the low level. I considered putting a new O2 sensor in the 93 - until I noticed that I will have to remove the heat shields to get a wrench on it. Also, adding that this O2 sensor [and exhaust] passed the test 2 years ago,and has not been on the car since. Although, the test 2 years ago didn't have the idle test.... But then there is the similarity of the 2 cars. Note - the 87 happened to level off by the time I took the picture. I revved it for a bit, and it began cycling again. The 87 is the "reference" car, it had its final test a few years ago.

They made a few that worked.... it seems to be like the clocks in GLs & loyales. Out of about 7, only one worked long term. I came up with a mod that fixes most of them permanently. I don't know if the digital dash had the same kind of silly design compromises that the clocks had, or if whatever fails is more complicated.

Ah, That's a thing I did not know. I skipped most of the EJ. I can't go re check the 01 since we sold it a year or so ago.

Wagonist is correct. I thought 24 was too small also. I just checked my wheel nut socket. It's a 36mm. It works on every Subaru I have used it on from 1976 to 2001.

To find the whirring noise, get a 3' length of tubing, 3/8 or 1/2". Hold one end near an ear, the other near various suspect moving parts. Do similar with a big screw driver or similar tool. Be careful not to touch any moving parts. Whirring noises typically come from ball bearings that are getting ready to fail.

After a bit of delay, I had a chance to hook up my oscilloscope to the O2 sensor. These were taken after warmed up. 2 seconds per division Horiz, 0.5V per division Vert. Checked that the exhaust system is grounded well beforehand. The first one has the short flat line [far left] showing the zero V reference position.

they have "default" settings so you are not stranded by a sensor failure. That may be coming into play.

Subaru engines are made to spin fast, not lug. I am most familiar with the older ones, but 3-4000 rpm is not stress.

That daytime light stuff started before 09. Are the bulbs in the HID failing? They have only so many hours that they can last.

Yeah, that could do it. I guess it's a good idea to check by turning the crankshaft with a wrench when something like this happens. I have not had or seen this happen, so didn't even think of it based on the description of what was happening.

Wow, that's an unusual one! Any idea how it got that way?

I've been using Hammerite Waxoyl for many years. Stops and prevents rust. Great for areas that don't show. Soaks into places you can't get to. On my Loyale wagons, I noticed how the mud flaps and part of the fenders trap dirt and crud. So I modified them to block the path stuff was getting in, and made sure there is a way for it to drain out. On the newer models, watch out for plastic pieces that cover and "protect" areas near the bottom / wheel wells. They hide the rust until its too late.

Up higher in this thread, there is a real electric one mentioned. If you are talking about a 4-5 HP motor with a proper compressor for an engine about the size of 1.8L then it's a real thing. An electric motor of that HP takes about 4-5 kilowatts. 4KW at 12 volts means you need 333 amps. Of course, this scales up and down with engine displacement.

Up higher in this thread, there is a real electric one mentioned. If you are talking about a 4-5 HP motor with a proper compressor for an engine about the size of 1.8L then it's a real thing. An electric motor of that HP takes about 4-5 kilowatts. 4KW at 12 volts means you need 333 amps. Of course, this scales up and down with engine displacement.