What is the Distributor O Ring all about?

The distributor plays an important role in producing power for your vehicle. It receives electrical pulses from the ignition coil and disperses them to the appropriate spark plug through the spark plug wires, which ignites the air/fuel mixture in the combustion chamber. The distributor shaft is mounted in the engine, either through the intake manifold or into the engine block.

Any amount of moisture inside the distributor can and will cause a rough run and loss of power, so it is critical to keep it as dry inside as possible. There are actually two seals on the distributor shaft; one seals the shaft to the intake manifold or block to prevent external oil leakage, and one is a shaft seal where the distributor shaft enters the distributor housing to prevent oil from entering inside. Both seals are intended to keep oil inside the engine, not in or on the distributor. When the distributor o-ring in the intake is leaking, oil and grime builds up on the exterior of the distributor and the intake. If the distributor shaft seal is leaking, oil enters the distributor up the distributor shaft, albeit in small amounts, and prevents the proper transmission of the ignition spark. This will cause the engine to misfire and run poorly, along with a lack of power.

Keep in mind:

• Pulses of high voltage electricity go through the distributor and spark plug wires. Disconnect the battery before servicing the distributor.

How it's done:

• The Distributor O Ring is verified that it needs to be replaced. The battery is then disconnected and the distributor cap is removed.
• The distributor is removed and the defective Distributor O Ring is removed from the bottom of distributor.
• After the new Distributor O Ring is installed and the distributor is reinstalled, the engine timing is set
• The engine is started and the Distributor O Ring is tested for leaks.
• The vehicle is road tested to ensure proper operation of the Distributor O Ring and timing.

Our recommendation:

The distributor cap requires regular servicing and inspection during an engine tune-up. If oil is noticed in or around the distributor, the distributor o-ring or shaft seal will need to be replaced by one of our expert technicians. Sometimes the distributor itself will need to be replaced if the seals are not serviceable separately.

What common symptoms indicate you may need to replace the Distributor O Ring?

• Noticeable oil leak at the base of the distributor by the valve cover
• Rough run and loss of power

How important is this service?

An external oil leak from the distributor o-ring is almost always a minor concern that can be addressed in time. An internal distributor oil leak needs to be addressed immediately as it can lead to power-robbing symptoms which can leave you in a dangerous situation while driving.