DETROIT DIESEL 53
CRANKSHAFT OIL SEALS
An oil seal is used at each end of the crankshaft to
oil seal bore. Then press or drive the oil seal out of the
prevent the lubricating oil from escaping from the
housing. Discard the oil seal.
crankcase. The seals also provide protection against
the entrance of dirt, dust, mud or oil from the external
4. Clean the oil seal bore in the front cover or flywheel
portion of the engine (Figs. 1 and 2).
housing thoroughly before installing a new oil seal.
The front oil seal is pressed into the lower front cover.
When necessary, the crankshaft oil seals may be
removed without removing the front cover or flywheel
housing. This may be done by drilling diametrically
A single-lip oil seal is used at the rear end of the
opposite holes in the seal casing and threading metal
crankshaft. The rear oil seal is pressed into the flywheel
screws, backed by flat washers, into the casing. Then
the seal may be removed by prying against the washers
with pry bars.
Remove Crankshaft Oil Seals
1. Remove the engine front cover, or the flywheel
housing and remove the oil seals as follows:
Oil leaks indicate worn or damaged oil seals. Oil seals
2. Support the forward face of the front cover, on two
may become worn or damaged due to improper
wood blocks next to the oil seal bore. Then press or
installation, excessive main bearing clearances,
drive the oil seal out of the front cover.
excessive flywheel housing bore runout, or grooved
Discard the oil seal.
sealing surfaces on the crankshaft. To prevent a
repetition of any oil seal leaks, these conditions must be
3. Support the forward face of the flywheel housing on
checked and corrected.
two wood blocks next to the
Inspect the front and rear end of the crankshaft and the
crankshaft front end for wear due to the rubbing action
of the oil seal or dirt build-up.
Fig. 1. Crankshaft Front Oil Seal
Fig. 2. Crankshaft Rear Oil Seal
1972 General Motors Corp
SEC 1.3.2 Page 1