A couple weeks ago I was driving and my 1991 toyota with a 22re seemed to be bogging down a bit and about 15 minutes later it stalled so I steered it to the side of the road and popped the hood. It was overheating super bad so I let it cool down for a bit and then decided to try to get it home (was about 5 min away) as I was going up a hill it started losing more and more power so i pulled it over, popped the hood and looked. It was overheating again and for the first time I noticed the oil everywhere so I checked the oil and there was none in the oil pain so it was very low. So I went and bought some oil and it had a chance to cool down since then and then decided to drive the 2-3km more home. It was driving OK after the oil, but it def had less power than normal and my top speed was probably 80-90km/h then when I got to the highway turnoff to my house the engine started knocking and it really lost a lot of power, but now I was 1 minute away so i drove it home. So i looked at it again and it appears the knock is coming from the top part of the engine so i took the rocker arm cover off and nothing was too apparent and we turned the engine by hand and couldn't feel/hear/see anything unusual.

Any suggestions before I attempt to rebuild/replace it?

 

sounds like the headgasket is shot

 

Overheated twice and ran almost out of oil?

Throw it away and get another motor. If it overheated 2 or three times and almost completely ran out of oil I'd be hesitant to even try rebuilding it. Even if you get everything resurfaced and bored, there's no guarantee that there's not a crack or weak spot somewhere.

You'd be better off getting another motor at the junkyard and either running it as is or rebuidling that one.

If you ever wanted to try doing an engine swap now is the time...

 

Don't throw away the engine. If you plan on a rebuild have the block maganfluxed and the head rebuilt and pressure tested.

 

Deffentialy keep your old engine and use it it can be fixed..Cast iron blocks can take some abuse now the head is another story...But my $.02 is a engine overheating once is bad and twice is worse...

 

I don't want to beat you up after the fact, but you should Never, EVER, drive an engine in those conditions! You probably did considerable damage by continuing to drive it after overheating & knocking (a bad, bad time to be running an engine!).

The engine will have to be torn down to know for sure what was destroyed but I guarantee you something was definitely screwed up...
Good Luck.