How to Troubleshoot High PSI in the Oil Tank on a Harley


There are four likely causes that an oil gauge on a Harley might indicate high oil pressure. Two of the causes are literally connected to the oil tank. In order of probability from most to least, your oil pressure gauge is faulty or the electrical connection is loose; your crankcase vent line is clogged; either your oil return or your oil feeder line is kinked or blocked; or finally, your oil tank is overfilled. Work the problem in a few steps.

Things You'll Need

  • Screwdrivers
  • Pliers
  • Drain pan
  • Oil filter wrench
  • Replacement oil filter
  • Open end wrenches
  • Wire
  • Motorcycle motor oil
  • Drain the oil from your oil tank into a drain pan by loosening the hose clamp on you drain line with a screwdriver and removing the oil drain plug with a pair of pliers. Replace the plug and drain line after the oil drains from the oil tank.

  • Remove the oil filter from the front of your bike with an oil filter wrench. Drain the oil from the filter into the drain pan.

  • Discard the old oil filter and install a new filter hand tight onto the oil filter stud.

  • Follow the wires from your oil pressure gauge top the crankcase and check for loose connections or an obviously defective wire.

  • Inspect the oil feeder and oil return line from the crankcase to the oil tank. Physically remove the lines by unfastening any hose clamps with a screwdriver and any permanent fittings with an open end wrench.

  • Stick a wire through the length of the hoses to ensure the hoses are not clogged. Replace the two oil lines.

  • Follow the oil vent line from the top of the oil tank next to the return line to the crankcase. Remove the line from the crankcase with an open end wrench. Pull the line out of the oil tank with your hands.

  • Sick a wire through the vent line to ensure it is not clogged. Replace the vent line with an open end wrench.

  • Add the appropriate amount of oil, either 3 or 4 quarts, to the oil tank as specified in the owner's manual for your Harley. Turn over the motorcycle for about 15 seconds.

  • Remove the fill plug and read the dipstick to ensure the oil level reads full. Start the motorcycle and check the oil gauge. If the gauge still indicates that your oil pressure is too high the gauge is probably defective.

Tips & Warnings

  • Dynas do not have oil tanks.

Related Searches


  • Instructions Braided Oil Hoses
  • "Harley-Davidson FXD Twin Cam 88"; Primedia; 2004
  • "2005 Harley-Davidson Service manual"; Harley-Davidson Motor Company; 2005
  • Photo Credit Matt Cardy/Getty Images News/Getty Images
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