What I know is fairly limited. The car belongs to a mates son who hasn't owned it for long.
Fluids and timing belt were replaced soon after purchace - everything measured fine.
Everything seemed ok ... until it didn't
Dropping the sump showed big-end #4 had slop measured in mm, but the timing was spot on.
Skipping ahead, the big-ends and mains are both 0.010" undersize and the pistons are 0.020" over.
So it looks like somone stuffed a rebuild, patched it and flogged it off hoping it'd be out of sight when it dropped it's bundle.
I think the deformation was brute force rather than heat. The engine was still running, but went from "normal" to "can't ignore" over 50km - on the freeway anfter a weekend away in the bush.
I've never been inside a 300tdi, but this valve looks ok to me. Confident it "wasn't there at the time"
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