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Cat Man
Cat Man, Caterpillar Engine Expert
Category: Heavy Equipment
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Experience:  23 Years Caterpillar Engine experience.
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C15: Seems to be alot of oil coming out the breather tube lately

Resolved Question:

I have a 05 cat c15 acert. Seems to be alot of oil coming out the breather tube lately.
Submitted: 5 years ago.
Category: Heavy Equipment
Expert:  Cat Man replied 5 years ago.

Hi. Thanks for using JA! I will try and help you out.



It sounds like your engine may have high crankcase pressure. High crankcase pressure can be caused by 3 things.


The first is the engines air compressor. When it becomes worn, it will allow it's own compression to enter the engine and cause oil to come out of the breather tube.


Second is the High Pressure Turbo. They can allow exhaust gas to enter the crankcase through the oil drain tube of the engine.


And lastly, is cylinder wear in the engine.



I would advise having the crankcase pressure measured to see if it is high. If it is, one of these 3 items is most likely causing your problem.


Please let me know if you have more questions.

Customer: replied 5 years ago.


Did the acerts not have a problem with this? I had read that cat has a kit to go on the breater tube to collect the oil & put it back in the pan?

Expert:  Cat Man replied 5 years ago.

Yes some of the C15 ACERTS did.


But first we would measure the crankcase pressure first to see if the crankcase pressure was high. If it was, the problem was always one of the 3 items I mentioned before.


However, on occasion we would have one that did not have high crankcase pressure and the customer would OPT to install the Secondary OIl Breather on the engine.


The most important thing is to measure the blow by. If the Secondary breather assembly is installed on an engine and the engine has high crankcase pressure, you will still get oil out of the breather.


Please let me know if you have more questions.



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