First off I am an engineering student who works full time but might leave one of my two jobs depending on the "best" answer to my problem. I have a stock 1990 GX(L?) with ~150 000 km on it.
Now onto the actual question. About mid August my alternator belt and thermostat went. I had to drive it for approximately 5 minutes with me stopping every 45 s and waiting a while the temp to drop back down I never let it get above the 2/3 point. I finally had time to fix it and so I did yesterday. But I started it and a whole bunch of white smoke came out and won't stop, the engine bucked around in the bay, and it sounded almost like it was bridgeported too. So is my engine blown? If yes what is the best way to fix the problem:
-"new" engine
-rebuild engine
-get rid of it and buy another one (preferably an SE like my first)

 

The problem with the '90 temperature gauge is that it isn't real. It really only has three positions: cold (bottom), normal (middle) and "new engine" (top).

You may have damaged the coolant o-rings. Take off the rad cap with the car stone cold and then start the engine. Do you see a steady stream of bubbles coming from inside the engine, that increases when you rev the engine? If so, then you probably have lost an o-ring.

What you do now sort of depends. Looking for a project? Rebuild it, knowing that you may need to replace some internal parts if the engine has been sitting with water in it.

Want to get back on the road quickly? Find a good used engine and swap.

 

I can't check it until Tuesday because I am working and it is in a storage compound right now. It's currently my only vehicle right now, I just sold my other car only to find this problem. I will check it then and post what happened.