• A-1 Engine Repair
  • Questions 1-10
  • Questions 11-20
  • Questions 21-30
• A-2 Automatic Transmissions
  • Questions 1-10
  • Questions 11-20
• A-3 Manual Drive Trains and Axles
  • Questions 1-10
  • Questions 11-20
• A-4 Steering and Suspension
  • Questions 1-10
  • Questions 11-20
  • Questions 21-30
• A-5 Brakes
  • Questions 1-10
  • Questions 11-20
  • Questions 21-30
• A-6 Electrical / Electronic Systems
  • Questions 1-10
  • Questions 11-20
• A-7 Heating and Air Conditioning
  • Questions 1-10
  • Questions 11-20
• A-8 Engine Performance
  • Questions 1-10
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Engine Oil Presssure

 

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 fail if debris in the oil gets caught in the housing causing premature wear and damage. If the pickup screen gets clogged this will cause a restriction to oil flow and a loss in oil pressure.

Bearings are designed to wear and are replaced when rebuilding an engine. The growing gap between the bearing and the journal increases the flow which in turn lowers the oil pressure. More flow less oil pressure.

Worn crankshaft, camshaft, and rod bearings will all cause a loss in oil pressure. There are different 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. This may indicate a problem with a worn or damaged part such as a twisted rod.

High oil pressure may be present. 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. High oil pressure can result in oil leaking past the oil seals and oil leaks in other areas the engine.