I fitted a new battery and tried to crank up the engine of the wagon. It turned over and came to life for a brief few seconds, then it died and spewed dirty looking oil through the air cleaner box! I tried again after cleaning up all the affected parts and the same thing happened. Looking into the valve cover through the oil filler hole I saw sludge and gunk all over the place. Time for a top overhaul.
Under the valve cover was a very sorry sight – it was not just sludge; there were also traces of water and the camshaft lobes and the followers below were badly rusted! Many have advised not to use anything more abrasive than the Scotch-brite type of scouring pads to clean the camshaft but it did not get me anywhere. I had to use fine sandpaper lubricated with WD-40 to rub the rust away.
On the other side of the head, I noted that combustion chamber #4 was exceptionally clean; even the spark plug was very shiny. I thought either there was never any spark there, or no fuel/air mixture was ever injected in there. That explained the poor idling and the engine’s tendency to die off in Drive as it was running on three cylinders. That was how it ran three months ago, before thing got worse while it was supposedly being fixed.
The valves were hand-lapped the old-skool way with rubbing compound. The cam followers were cleaned the same way with sandpaper but I flipped them over during re-installation so the rusted side faced down. I also took the throttle body apart and cleaned it, and re-aligned the throttle butterfly and the switch.
The injectors that came with the engine were another sad case. They were meant for turbo applications and of two different part numbers. One had no pintle cap and another had both the pintle cap and the lower o-ring missing. Luckily a couple of friends were able to quickly source for me a set of orange tops that Volvo specified for this engine, otherwise reassembly would have to be put on hold.
Next was to drain the oil sump. What came out of the crankcase was not black engine oil but muddy mixture of coolant, petrol and oil. A lot of petrol must have been forced into the crankcase as the smell was so strong. I tested it with a lighted match on a pile of rubbish and it caught fire instantly. I am currently considering to give the engine a flush with kerosene. I know there are two schools of thought on that…