Fig. 8. Checking Bottom Face of Cylinder Head
Inspect Cylinder Head
Fig. 7. Cylinder Head Prepared for Pressure Test
using Tool J 28454
1. Before a cylinder head can be reused, it must be
inspected for cracks. Five prescribed methods for
16. Remove and discard the cylinder head compression
checking a cylinder head for cracks are as follows:
gaskets, oil seals and water seals.
NOTE: If any method reveals cracks,
17. After the cylinder head has been removed, drain the
the cylinder head should be considered
lubricating oil from the engine. Draining the oil at this
unacceptable for reuse.
time will remove any coolant that may have worked its
way to the oil pan when the head was removed.
Magnetic Particle Method: The cylinder head is
magnetized and then covered with a fine magnetic
Disassemble Cylinder Head
powder or solution. Flaws, such as cracks, form a small
local magnet which cause the magnetic particles in the
If complete disassembly of the cylinder head is
powder or solution to gather there, effectively marking
necessary, refer to Pages 10-2-38 and 10-2-29 for
the crack. The cylinder head must be demagnetized
removal of the exhaust valve and injector operating
after the test.
Fluorescent Magnetic Particle Method: This method
Clean Cylinder Head
is similar to the magnetic particle method, but is more
sensitive since it uses fluorescent magnetic particles
After the cylinder head has been disassembled and all
which glow under a "Black Light". Very fine cracks,
of the plugs (except cup plugs) have been removed,
especially on discolored or dark surfaces, that may be
thoroughly steam clean the head. If the water passages
missed using the Magnetic Particle Method will be
are heavily coated with scale, remove the injector tubes
disclosed under the "Black Light".
and water nozzles. Then clean the cylinder head in the
same manner as outlined for cleaning the cylinder block
Fluorescent Penetrant Method: A highly fluorescent
liquid penetrant is applied to the area in question. Then
the excess penetrant is wiped off the surface and the
Clean all of the cylinder head components with fuel oil
part is dried. A developing powder is then applied which
and dry them with compressed air.
helps to draw the penetrant out of the flaws by capillary
action. Inspection to find the crack is carried out using a