This is a 1.9 SDI engine. It was running on 3 cyl.and produced a lot of smoke. I diagnosed a compression loss on cyl #4. Pulled the head and #4 piston was sitting lower than #1(?). Maybe a bad bearing shell or bend rod. Pulled the oil pan and indeed a bend rod. Replaced the rod. I then serviced and cleaned the head but one thing wasn't right. Almost all the hydr. valve lifters were damaged. Dents and cracks were the cam hits the lifter. What could cause this? Maybe they didn't subtract and the pistons hit the valves(?) but I found no traces on the piston. I replaced all the lifters and let them settle over night. Finished the work and started the engine and it was running very smooth, no smoke or vibrations. I could here the valve lifters knock but thats normal with new lifters. Let the engine warm up until suddenly a loud ticking noise and then bang!!. I couldn't rotate the crank by hand, arrgh. Checked the timing but it was spot on. Pulled the head again and #2 exhaust valve was broken in four pieces!! I examined all the parts but I can't find any explanation why the valve obvious stayed open hit the piston and broke. Could a high oil pressure cause the lifter to lift the valve? This diesel has only one valvespring /valve so there's not much oil pressure needed to lift it.
SFC