Hello,
This is my first post. I bought a 92 4x4 four months ago. Rebuilt the automatic transmission ($2900) and several oil changes are all the work I have done. A new problem arose today. I drove it home after Father's Day Lunch (ran fine), took a nap then got up to run errands and the 4runner wouldn't start. It was a new noise that I have never heard in any of my previous autos. It made a loud clunk sound like something was holding the crankshaft and not letting it turn over. Electrically it sounded fine, no starter clicking or anything. I tried it two more times...same thing. I let it sit for a minute and checked under the hood...no obstructions and tried it again. It fired up but now it smokes. The head gasket has been replaced a couple of years ago but has not been running hot. I am puzzled about this one. Any help would be greatly appreciated. Let me know if you need any more info on the 4runner.
Jay

Have you checked the coolant and oil levels? Does the oil look like coffee ice cream? White smoke is indicative of a blown headgasket or something wrong with the fuel system. Does it smell like coolant or raw fuel coming out of the tailpipe? Do a compression check. Look at the spark plugs and describe what they look like.

Sounds like you had a fluid lock in one of your cylinders - caused by antifreeze leaking into one of your cylinders. Bad head gasket is most likely cause. Change it immediately before you trash your engine by diluting your oil.

Also, make sure you check your head with the blown gasket for straightness.