Caterpillar D3412TA engine overheating

During the routine testing of an offshore D3412TA fire pump engine, the operator reported that it was overheating. They checked the seawater and jacket water systems, but there was no obvious fault with either, so they called Bartech Marine Engineering in to carry out an investigation.
Initial investigations showed that water was being blown out of the header tank after a few minutes of running. That is a result of back pressure from the cylinders.
The next thing was checking of the cylinders to understand the cause of this back pressure, and was found that water was getting into cylinder 8 under static pressure. The borescope was taken out and worked out the root cause – the pre-combustion chamber. It had corroded over time, along with the seal, so it wasn’t sealing and letting water in. The chamber and the seal were changed, the back pressure problems were eliminated and the engine brought back on-line.
This isn’t the first time issues happen with these parts, so if you’re using 34 series engines, or you have pre-combustion chambers, you need to make sure these are checked or changed at appropriate intervals to protect your engine.