I have a 97 4runner 3.4 with 210k. Noticed rough idle and white smoke at start up a few days ago. Both would clear up. I assumed head gasket. Added coolant yesterday and drove 10mi. Went to start up today and engine wont turnover(starter is fine). Is it possible coolant filled cyl while sitting(hydrolcked?), and if so would trying to start damage rods? Any advice greatly appreciated, thank you.

 

Try to turn the engine over with a big ratchet or breaker bar via the crank bolt. If it won't turn take the spark plugs out and watch as someone else turns it over via the starter. Watch the coolant shoot out to see which cyl it is.

If it will turn over with a ratchet I'd say your starter is acting up. Starters are strong but I'm not sure if they are strong enough to bend a rod.

 

Starters will bend a rod. I have seen it with a leaky fuel injector on a small 4 cylinder car.

Pull the plugs and crank it over. No crank means starter(or related)

Coolant gushing out in a Fourth of July celebration means head gasket