Engine restore is like STP where it thickens the oil.
This is the wrong time of the year for most of us to thicken oil, but it works.
Synthetic oil works also to slow down oil consumption as it is sticky’er and is less likly to burn off also.
What am impressed with is how the CAT system keeps these old oil burners from spewing a big blue cloud like the oil burners from 50 years ago!
About 20 years ago I had a Civic that was burning a lot of oil.
I changed the oil to synthetic, and that reduced the smoking, but then the smoke
smelled like popcorn. 
I’m still concerned as to why the engine stopped running.
Overheat? Blown head gasket?
Before tearing it down and installing a bunch of new parts, I would do some serious diagnostics and make damn sure there is no engine damage, or you could just be putting lipstick on a pig.
Progress report on replacing the water pump. Just so you can kibbitz, laugh and point, etc., (which you are fully entitled to).
Day 1: Disassembly. The YouTube video in my 2nd post is mildly helpful. Got the old pump out. Clearly failing as it was leaking from the rotor.
Issues: Broke a bolt off on the water pump pulley. Not much of a problem since the old pump is gone. Just need to get a new bolt.
The timing belt looks pristine. And I know it’s been in there a while. That’s a good sign that the compartment hasn’t seen too much water or anything.
Got a gasket on the flange that connects to the lower radiator hose that is stuck on quite well. Gotta get some gasket remover. I’m also going to replace the lower radiator hose since it’s clearly soft and possibly leaking. (The upper one is “new”, i.e., merely about 14 years old.)
The usual complaints about tight clearances applies. Good freakin’ grief, why do they design things this way? E.g., the flange is held on to the pump by two bolts. The lower bolt is blocked in by the top of the flange, the AC compressor, the oil dipstick and some other stuff. Had to work the bolt off 1/16th turn at a time with an open end wrench. About a third of the bolts couldn’t be accessed with a socket wrench.
As to actual status of the rest of the engine? Don’t really know. I ran it a couple times to make sure it started, etc. But didn’t really want to press it with the coolant leak.
Replace the timing belt while you’re there. Well worth the cost.
I know you’ve all been waiting on pins and needles for the final report on the situation.
Anyway, I went ahead and replaced the water pump. For a car this old, getting many parts without ordering is getting harder to do. But luckily, the water pump on this car was used on a lot of later Mazda engines.
I really screwed up the first attempt at the install. Ended up ruining the gasket. So got a replacement, etc.
It runs fine. No leaks. No oil in the coolant, etc. I did a bunch of other maintenance while I was at it. New plugs (the old ones had a lot of hard white crud on them), oil and filter, etc. I also added some gas conditioner since the car was struggling for a few seconds on cold start up. Now it really hums.
I’ve been driving it around for a few days. I really miss driving this car. Love manual transmissions.
Took the plunge and replaced the nearly bald tires. Big $ but it wasn’t safe on the old tires. Going to have the kid kick in for all of this.
Cost for the initial repair was probably under $100. I bought several tools but I’m amortizing those costs. (Ratcheting wrenches to get into the tight spots, a new torque wrench.)
But it sure took a lot of time. Could only work a little on it here and there for the most part. Really hard to get one of the old gaskets off. (Attention Permatex: your “gasket remover” is useless.)
The estimates given above for $300+ for labor is low in my opinion. I could easily see how the hours would just rack up on a job like this.
I wasn’t happy as I worked on the car as it was clear the kid hadn’t been doing some basic maintenance. But then I went to write in the notepad I keep in the glove compartment. I write down everything from gas fill ups, to oil changes to new parts. The kid had been keeping it up! Hey, something was actually sinking into the kid’s brain. Love it.
Thanks again for all the fine info that has been posted here.