Few months ago our 1999 Escort Wagon (third North American generation, standard 2.0L CVH motor, about 120 000 miles (roughly 200 000 km)) exited the building with a bang. That is, driving down the street loud bang occured, and it died. It was possible to start it afterwards, but it would run really loud, and have no power. It was necessary to rev it really high just to get off the road. If that matters, oil on the dip-stick was clean, with no metal shavings, coolant or any other contaminants.
Now that the weather is warming up, it is time to access the situation, and see if the car can be salvaged. When we took it to the mechanic, they said it was “probably” the piston rod that broke, and it was cheaper to replace the engine ($1500 for refurbished one, with labour included) than to rebuild what was there. I was not willing pay that much to fix 13-year old car we just recently bought for $2000. Also, a friend told me that if the rod broke, it was unlikely it would turn at all.
Later I’ve been told that there is a common problem with CVH engines: valve seat can drop, causing all sorts of damage. It is said that it often happens without warning, but I must admit the car was running rather loud, and was a bit sluggish when we bought it. In the hindsight, we shouldn’t have, but it was otherwise so clean, and well-maintained, I closed my eyes on that at the time.
So, the questions are, where should I begin? Would it be obvious what happened by taking off valve cover and/or intake manifold, or should I remove the whole head? What can I see if I drain the oil, drop the pan, and take a look at the bottom end? Given that it was run at least for two to three minutes afterwards (to get it off the road, and later to check what is happening), would the damage be too extensive (pistons, head and cylinder walls, bent rods), or, at least, how do I determine that? Depending on the extent of the damage, can most of this be repaired without taking out the motor?