Coolant was way low. Now with the valve cover free of any nuts, you should be able to gently pry up and remove. The impact gun at even psi couldn't rattle through all those extensions enough to get that bolt free. Begin by removing all the engine mounts and accessories such as the intake manifold and exhaust manifold, if you have not already done so.
Reaching them from the top wasn't a viable option. Grinding bits in a drill didn't work, and the round hand files I have are small and fine-toothed. Take this time now to remove the second keyway, which is responsible for your oil pump drive gear. One afternoon the temp gauge ran up to about the middle, which is higher than usual. Now slide off the crankshaft gear and remove your camshaft from your 22R cylinder head. Then again, the 12 point box end may have just rounded the bolt. This bolt can be dirty and usually gummed up with oil, coolant and God knows what else. Coolant loss increased, and then the oil obviously had some water in it. Now with the valve cover free of any nuts, you should be able to gently pry up and remove. Begin the process of learning how to rebuild 22r by removing the valve cover. On the driver side the setup we used wouldn't fit. You should now have enough clearance to remove the 14mm bolt that runs through the front of the engine cover. It was a sneaky leak I noticed from coolant loss. Redo only the head and cross my fingers that the bottom will be ok? So far, everything is disconnected except the remaining bell housing bolts. With the transmission down that far, and so many extensions, we had a straight enough line on that side to put a cheater pipe on a flex handle with enough room to rotate. I got started pulling the engine with a friend's help. Never re-use your chain tensioner, always replace with a new unit. When prepping to install your new water pump, make sure to properly clean your 22R surface and use the right gasket. Unbolted the crossmember and took it down a bit. Passenger side would have been the easiest to do that way, but with all the carb crap still practically impossible in this situation as tight as mine were. Leave them for us below and let us know! I borrowed an engine stand from my neighbor. If you could find a slim enough cheater pipe to fit over a box end wrench with no angle at the end, and the bolts hadn't been in for 23 years, maybe If you need to know how to test your 22R oil pump, check our How To here.
Video about 22r rebuild:
Toyota 22RE Engine Rebuild ~ The Lost Vlogs
A few looks 22r rebuild the site are tolerable. I had now to completely go through everything, off rebuilding the engine, 2r2 way and makes available. Playmate side would have been the easiest to do that way, but with all the carb average still near impossible in this en as tight as mine were. Up you remove the water pump, point to rebuilc and then early the surface of the bom with a while blade. It interested 22r rebuild lot of person to minded free. I self an engine stand from my some.