# Locked up Volvo Penta MD2B engine



## georgehcoton (Sep 22, 2018)

My Mercator Offshore Mk II sailboat has been layed up for refurbishing, and I have been hand cranking the Volvo Penta MD2B diesel engine to keep things lubricated. The last time I turned the engine over with the hand crank, there was a clicking sound, and now she will not turn over with the hand crank, or by using the starter, of manually trying to turn the flywheel. Best guess might be a pushrod popped out of alignment? Any suggestions as to what happened?


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## Capt Len (Oct 9, 2011)

Is the boat in the water and turning the engine over has filled/hydrauliced the engine. If so ,start by draining the muffler and pull the injectors and check the dip stick.


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## expert (Sep 17, 2018)

well if the engine has hydraulic lifters then yes that's a good guess as one may have collapsed and because the particular valve was closed (rocker arm up) then its possible. easily proved by taking valve cover off and a quick look.


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## Jeff_H (Feb 26, 2000)

expert said:


> well if the engine has hydraulic lifters then yes that's a good guess as one may have collapsed and because the particular valve was closed (rocker arm up) then its possible. easily proved by taking valve cover off and a quick look.


Small Volvo Diesels, like most small sailboat diesels do not have hydraulic lifters.

What Capt Len is wisely asking about is 'Hydro-lock'. Hydro-lock is a condition where a boat is in the water with its raw water intake open, and has an engine that is turned over without actually being started. In doing so, the raw water pump is still pumping raw cooling water into the exhaust system. But without the engine firing, there is no force to blow that water out. The water initially fills the muffler and then starts filling the rest of the exhaust system until it fills the exhaust manifold and exhaust valve port. At that point when the exhaust valves are opened, water gets into the cylinders preventing the pistons from being able to move.

In some conditions (occurring while being cranked) hydro-lock can completely destroy an engine by bending connecting rods, damaging pistons and scoring the cylinder walls. In worst cases, the head can be damaged and crankshaft bushings can be damaged as well. Left unattended, it can also damage the injector, valves, valve seats and guides.

Jeff


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