Some news! Not much has happened recently. I've replaced the faulty ABS sensor on the Lincoln which fixed all the related issues, was fairly straight forward aside from having to heat the bolt for 5mins before it came out.
I'm also currently investigating some fuel supply issues on the Merc. The control module controlling the fuel pump shutoff relay is known to have failing capacitors, hopefully having them replaced sorts out my hard starting issues which are only getting worse, independently from what the battery is doing.
I have also started taking the Corona's engine apart to get the timing belt driven waterpump out. The belt and pulleys are all looking excellent despite being original most likely. So is the waterpump, the bearing is completely shot however. Its so bad that it must have leaked through there actually. I'll call the dealer tomorrow to find out how much they want for the belt, otherwise I'll buy it all on Autodoc which has very reasonable prices for OEM supplier brand parts, about 90 quid all in incl. pulley/tensioner.
Naturally, getting there was an absolute pita, with the situation not being improved with this being a RHD car that has it's brake master cylinder right next to the damn timing cover. Engine mount, alternator and braket had to come out, power steering reservoir and all kinds of hoses and wires moved out of the way. Without removing the master cylinder I just about got the cover out, which was probably the hardest part of this whole ordeal. I actually had to use my Dremel to grind some of the plastic next to the bolt away to even get a spanner on there. Wtf was Toyota thinking??
This photo shows how much space there is. Jacking up the engine helps a lot getting a few extra mm of clearance here and there.
Ah, the infamous Toyota waterpump gaskets...
So the sludge I've suddenly seen appearing (and originally letting me assume the worst) really must be just old gunk that suddenly reappeared in the system. You can see how bad the thermostat got caked in it.
The solution was pretty straight forward. Take pressure washer, aim at radiator fill neck, ziptie the trigger and let her rip. That should have done the trick, I got clear water out of it in the end.
The thermostat is almost identical to the new original Toyota one (so probably still the original one), both open at the same temps. Yet the new one is longer. It fits without issues so I doubt theres anything wrong with it, just odd.
And thats it for now. Hopefully I can install the new parts in about 2 weeks or so, and my markings on the cam gear are accurate enough to not cause any timing issues. At least its a non-interference engine...