Brains Trust, Received a call out to look at a Hyundai 740-7 with a Cummins QSB 5.9 that made a rattling noise then stopped & would not start. The operator completed the normal checks , water, oil, batteries, battery leads etc, starter would clunk but not spin the motor over. The unit has now not run for 5-7 days, I arrived onsite & rechecked the basics & noted the dip stick showed a massively over filled sump (oil was normal colour) So dropped the engine oil. I drained 20l of clean water from the sump & 10l of oil. The water was clean, the oil looked normal. My initial thoughts are that the head gasket has failed, however I have never seen oil in a sump that is not emulsified, so I am a little confused to what may have caused this issue and hope the hive mind can help.
Pics of oil drained from sump & pics of oil filter, showing normal oil conditions with no water or emulsion!
You guys run straight water, not antifreeze? Where is Menzies
Menzies is in The North Eastern Goldfields of Western Australia
Ok, pulled the oil cooler apart to check if it had failed and allowed coolant into the sump, no water on the oil side & no oil in the water side, I then removed the head & found the intake valve on #1 has failed & embedded itself into the piston & bent the exhaust valve as well. Is it possible that when the valve has hit the piston and smashed up against the head it has allowed coolant to enter the cylinder that has then drained into the sump?
Also found the tip broken off the injector on this piston,
Not sure about the 5.9 but the 6.7 has a frost plug under the valve cover that can cause the oil and cooling system to mix if it started to leak.
Someone was operating this thing when it grenaded, and it would of made a lot of noise unless the operator was on some substance or had earphones on. That head probably has a crack, plus all the smashing of the piston would of junked it anyways. Water could easily have gone down the side of the cylinder wall and would of settled out in the pan after enough days. Who was operating this thing last. Big repairs on the way. Simon C
Dropped valve. Saw same thing last year on a Detroit series sixty. The valve head snaps off at the stem and falls into the piston which then crashes into the head and busts it open to the coolant. It killed the Detroit in about fifteen seconds. The engine was in a propane tanker on I5. Coolant won’t emulsify unless the engine can run. The motor was scrapped. Good luck with that one.