Maxxforce 13 Crankcase Breather Problems May 2026
The MaxxForce 13 engine, manufactured by Navistar, is well-known for its complex emissions systems, and the is a frequent source of trouble. When this system fails, it often leads to excessive oil being expelled through the road draft (blow-by) tube. Common Crankcase Breather Problems Failing Centrifugal Separator (Squirrel Cage)
Over time, the brass orifice can erode and enlarge. This reduces the velocity of the oil spray, meaning the spinner doesn't spin fast enough to separate oil. Simultaneously, the larger hole dumps more oil into the housing than the drain can handle, causing it to overflow out of the breather. Excessive Blow-by (Engine Wear) maxxforce 13 crankcase breather problems
The MaxxForce 13 uses a spinning "squirrel cage" separator driven by oil pressure to fling oil droplets out of the crankcase gases. The MaxxForce 13 engine, manufactured by Navistar, is
The "jet plate" is a brass orifice that sprays oil onto the centrifuge to spin it. This reduces the velocity of the oil spray,
While the breather itself can fail, it is often blamed for problems actually caused by "blow-by"—combustion gases leaking past worn piston rings or cracked pistons.
High crankcase pressure from worn rings can overwhelm even a functional breather, pushing oil and vapor out of every available seal and the draft tube. Key Symptoms to Watch For
If the bearings fail or the assembly becomes clogged with sludge, the spinner slows down, losing its ability to separate oil from air. This causes the system to flood, forcing raw oil out of the breather tube—sometimes at a rate of several gallons per day. Jet Plate Erosion
