Jones4WD
New Member
- Joined
- Mar 21, 2005
- Location
- Wake Forest, NC
Can someone knowledgable please explain to me what diesel blow by is? Also how do you tell if an engine has it?
Diesel Blow by
- Thread starter Jones4WD
- Start date
- Joined
- Mar 16, 2005
- Location
- Archer Lodge
Blow by,
pressure escaping past the rings during compression stroke.
ALL diesel engines have blow by to a degree, generally it's if the engine has it ( because it does ) it's how much it has.
A cyl leak down test will help in diagnosis, as will a compression test. knowing manufacturers specs for pressures is a must also.
http://www.expertdiesel.com/blowby.htm
As a result of all diesel engines haveing blowby, most have what is called a "draft tube" to vent the vapors out of the engine compartment. ( you will see steam/vapors venting from this on large engines ESPECIALLY if they are under load) very basic form of crank case ventilation.
pressure escaping past the rings during compression stroke.
ALL diesel engines have blow by to a degree, generally it's if the engine has it ( because it does ) it's how much it has.
A cyl leak down test will help in diagnosis, as will a compression test. knowing manufacturers specs for pressures is a must also.
http://www.expertdiesel.com/blowby.htm
As a result of all diesel engines haveing blowby, most have what is called a "draft tube" to vent the vapors out of the engine compartment. ( you will see steam/vapors venting from this on large engines ESPECIALLY if they are under load) very basic form of crank case ventilation.
- Joined
- Mar 24, 2005
- Location
- Stanley, NC
Diesel blow by: What happens when you are towing a heavy load with a gas truck.
P.S. I have nothing useful to contribute
P.S. I have nothing useful to contribute
maulcruiser
Well-Known Member
- Joined
- Aug 13, 2005
- Location
- Bladenboro/Wilmington, NC
If you have a significant amount of blowby, it will push oil out of the EGR valve or out of the seals.
depends on the diesel. PSD, gets leaks from the front and rear seals, CTD, you'll see raw oil at the vent tube on the 12V and "steam" from the vent at idle, dunno about the durmax, most of them will either push oil out somewhere or the vent will have oil running out. In extreme cases, it'll start burning the engine oil and run away.