| Free A.S.E. Study Guide An ASE Study Guide for the Automotive Technician |
| Engine Oil Pressure |
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A worn oil pump will cause low oil pressure. They wear in time and the clearance
between the pump housing and the gears, shaft end play, etc. gets excessive
resulting in a loss of oil pressure. Pumps also give out if debris in the oil gets
caught in the housing causing wear and damage. If the pickup screen gets
clogged this will cause a restriction to oil flow and a loss in oil pressure.
Worn bearings are the most common cause of low oil pressure. As mentioned
earlier as an engine ages the bearings are expected to wear and this will result
in lower oil pressure. The only way to repair this is by replacing the bearings.
The growing gap between the bearing and the journal increases the flow which
in turn lowers the oil pressure. Crankshaft, camshaft, and rod bearings will all
cause a loss in oil pressure.
There are many specifications and tolerances according to the application. Most
manufacturers and machinists will tell you no more than .001 inch off the
diameter of the bearing. Bearings should also be checked for scoring and
tapered wear.
There are several reasons for low oil pressure and something should be
mentioned about high oil pressure as well. A restriction in the oil filter a stuck
closed or clogged oil pressure valve will cause high oil pressure. This can be a
bad thing as well. High oil pressure can result in seals popping out of their bores
and oil leaks in other areas the engine.
between the pump housing and the gears, shaft end play, etc. gets excessive
resulting in a loss of oil pressure. Pumps also give out if debris in the oil gets
caught in the housing causing wear and damage. If the pickup screen gets
clogged this will cause a restriction to oil flow and a loss in oil pressure.
Worn bearings are the most common cause of low oil pressure. As mentioned
earlier as an engine ages the bearings are expected to wear and this will result
in lower oil pressure. The only way to repair this is by replacing the bearings.
The growing gap between the bearing and the journal increases the flow which
in turn lowers the oil pressure. Crankshaft, camshaft, and rod bearings will all
cause a loss in oil pressure.
There are many specifications and tolerances according to the application. Most
manufacturers and machinists will tell you no more than .001 inch off the
diameter of the bearing. Bearings should also be checked for scoring and
tapered wear.
There are several reasons for low oil pressure and something should be
mentioned about high oil pressure as well. A restriction in the oil filter a stuck
closed or clogged oil pressure valve will cause high oil pressure. This can be a
bad thing as well. High oil pressure can result in seals popping out of their bores
and oil leaks in other areas the engine.