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Pulled the engine from the son's 1992 240 that died from overheating. After getting it out, I couldn't resist tearing it down to see what the damage was.
The cam and upper valve train were in great shape. They looked almost new. My first thought was, "Oh, s***," I could have left the motor in, replaced the head gasket, and been just fine. When I pulled the head, it was a different story. Two cylinders (3&4) were filled with coolant (about 4 cm in #4 and 3 cm in #3). Nos. 3&4 con rods were broken. I guess trying to compress an incompressible fluid doesn't work too well! Cylinder number 2 had only residual coolant inside; however, it did have a little pie-shaped chunk missing from the edge of the exhaust valve. That saved con rod #2, but of course meant the cylinder wouldn't fire. Cylinder 1 was dry. For the record, these motors will not run as one-bangers!
The source of the coolant leak that caused the overheating, that caused head warpage, that allowed the coolant into the cylinders, that broke the con rods and valve proved to be a crack in one of the heater hoses. These things seem to be laid up with some sort of overlapping composite plies. It cracked at a seam! CHeck these things!
I very impressed with the performance of the bottom end. The crankshaft and main bearings survived with no apparant damage. Even the crankpin bearings, pistons, and piston pins looked to be in good shape. The motor could have been rebuilt. It might have even been possible to machine the head, replace the broken valve, and reuse the head.
Now comes the fun part... wrestling the replacement motor/tranny into place and reconnecting everything!
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Seven bricks, yep, six!
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What happens with a BAD coolant leak... [200][1992]