Hydro locked

Dear Tom and Ray,

After I replaced N0 4 fuel injector on my 1991 Q45 model, I start the engine up and heard a grunted and the engine locked sound. I tried to re-started serveral times, but the crankshaft would not turn. However, I was still able to turn the crankshaft manually back and fort about 45 degree with a socket. Would the connecting rod punch a hole or plow onto cylinder wall if a hydro locked did occured ? Do I have to replace the engine block then ?



Pull all the spark plugs out, and try to spin the engine. If it is the fault of ‘Hydrolocking’, then the fluid will spit out of the plug holes. If it is gasoline, change your oil as soon as possible. It is contaminated.

You should also disable the ignition where there will not be a spark provided. I saw a guy crank an engine over that had been hydrolocked due to gasoline and the gas spewing out of the spark plug holes became a real flamethrower when the plug wires set it off.
(Singed off part of his beard and the front part of the hair on top of his head along with scaring the beejeezus out of him.)

You may not have any engine damage. I’ve seen a number of engines hydrolocked that never suffered any problems, incluidng a few diesels. If you notice any abnormal vibration when it’s running then it’s possible you could have a bent connecting rod.

I removed all the spark plugs, and tried to turn the crankshaft with a socket and racheted wrench extended out with a longe tube I could only spin the crankshaft back and fort for not not more than a revolution then got locked up extremely tie that would not spin any futher. I used a long stick and drop it into the cylinder via spark plug hole but found not sign of gasoline (It possible drained down thru the gap between the piston and cylinder!). When I removed the air intake collector, I could see gasoline filled up fully the intake manifold whose fueld injector had once been replaced.
Any advice is apprecitated.