86 Honda Civic si

Took my honda to the mechanic to replace the valve cover gasket.
the antifreeze was changed, a fuel filter replaced.
They said they replaced the thermostat because there was not one, which was not true. There was a thermostat in my car and it was the same one after I left the shop that was in it when I brought it in.
Picked up the car, running hot, could smell oil and smoke coming from the tail pipe.
Car was running to the top of hot.
questioned this oil and smoke and was told it was an old car and seals are worn.
I told him it did not do that when I brought it in.
This car never runs hot.
car cooled down only low enough for me to get it home.
MENTION:
My cooling fan is wired direct to a fuse so have to use a toggle switch to turn it on. This was not done.
After parking the car at home, started it up a few minutes later and it surged so hard from 2000rpms to 0 and continued this up and down motion. At the same time there was a sounfd coming from under the hood that was as loud as someone hitting a hammer on the inside of the hood, in cadence with the surging.
oil fell out in globs.
Started it up this morning, to try and find the problems, the surging was from 1000 rpms to almost zero once agin with the same up and down surge and radiator fluid leaked out on the engine side.
Called the mchanic. No answer.
What happened to my car. I have never had this problem. It has always run great.
I know the mechanic is not going to admit anything, except the fact that he charged me parts and labor for a thermostat that he did not put in my car.