Regular Contributor

Re: Water from crankcase breathers drains of CAT 3516B

H2O (water) is a by product of combustion and consequently some water is in the combustion blowby gases that are in the crankcase.The function of the fumes disposal system is to allow the blowby gases to escape from the crankcase and flow to the outside. As the photo of your installation shows the blowby gases must flow upwards in your piping to escape.

When the water in the blowby fumes condense the blowby flow rate can be insufficient to lift the condensate and carry it the outside air.The condensate will then fall to the lowest point in the fumes disposal system and accumulate. This is what you obtaining when you open your drain valve. However your system does not have a condensate trap to allow a large volume of condensate to collect and be drained off regulary without restricting the flow of the blowby fumes. The condensate in your system will run back to the breathers and promote the formulation of emulsion which will be bolcked breathers.


New member

Water from crankcase breathers drains of CAT 3516B

Hi guys,


A small amount of water starts appearing from the drain valve of the crankcase vent line.


We checked LT/HT pumps control holes - no leakages,  LT/HT exp.tanks - water is clean,  Lub oil analysis - no water. 


I noticed that the water is appearing after the DG is stoped for 1-2 days and there is a water in next 24hours. After we drain the water a few times there is only oil again.


Any idea from where is this water?DSC01153.JPG