You know, there are some things that all the checks in the world probably won't catch...
Fallo of 2003 - three days before a fishing vessel is due to be delivered. Diesel engine tech has been onboard for two full days, checking over installation.
3:00 PM on a Friday afternoon, engine is started and allowed to run at low idle while it warms. Technician checks various operating parameters. All is well.
3:45 PM - Tehcnician performs a no-load speed test (presumably to test the electronic speed governor). At about 2400 RPM, we hear a huge "bang", a puff of black smoke and hear the sound of utter silence. Once the smoke clears, we find the side punched out of the block. Brand new $250K engine in junk.
Here's what forensics found:
The engine was equipped with a crankcase vapour reclaim system. Basically, a large foam filter in a canister that caught oil vapours from the valve cover and allowed them to condense. A hose from the bottom of the can ran to the oil pan, while another ran to the turbocharger inlet to burn off any remaining vapour. A check valve in the hose from the canister to the sump was supposed to prevent oil from being sucked up from the sump when turbocharger was pulling a vacuum. Guess what? The check valve was installed properly, but there was no ball or spring in the body! Running the engine at high speed created sufficient vacuum to pull oil from the sump into the turbocharger, where it was eventually injected with air into the cylinders. Oil doesn't compress that well, hence the catastrophic connecting rod failure...
The poor technician was physically sick. Poor guy did everything by the book, but short of disassembling the hose assembly to inspect the check valve for guts or blowing through the hose, there was no way he could have found the issue.
Of course, engine manufacturer denied any and all liability, including cost of replacement engine, removal and reinstallation cost, lost time, etc. Eventually, however, we did get a new motor out of them. Lawyers ended up getting rich over this one!