How do I change this O ring . I don't know where timing Mark is to bring #1 piston to TDC prior to removing the cap and Distributor from the engine to make it easy to drop it back in after O ring is replaced.
My car has 131000 miles.
My car has an automatic transmission.
On your ’86 Cadillac Deville, you should be able to find the timing marks down toward the bottom of the water pump. There will be a cylinder looking tube attached to it with numbers on it reading from 0-20. These are degree indicators for ignition timing. If you do not feel comfortable performing this yourself, I recommend having a trained technician, such as one from YourMechanic, replace the distributor O ring for you.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing