A rope seal, also known as a wick seal, works by absorbing oil and swelling, thereby making an oil-tight seal against the engine's crankshaft output flange. Over time, the seal can wear and cause engine oil to leak. A new rope seal is installed by cutting it to size and installing it in the rear main seal groove. This type of seal was popular in older Pontiac engines such as the 400 cubic-inch and 355 cubic-inch V8s. The proper way to replace a rope seal is with the engine removed from the vehicle and on an engine stand, disassembled for rebuilding.
Turn the engine upside down. Spray brake cleaner into the rear main seal groove. Dry the groove with a shop rag.
Apply a thin bead of high temperature gasket sealant to the rope seal groove.
Work the rope seal into the groove with your fingers. Start at one end and push it into the groove from one side to the other. Use a wooden dowel like a rolling pin to help push the seal into the groove evenly. Be careful to not twist the rope seal.
Use the razor blade to cut the rope flush with the of the engine block. Make the cut as straight as possible.
Repeat Steps 1 through 5 to install the rope seal in the bearing cap.
Apply a small dab of high temperature gasket sealant to the cut ends of the rope seal before assembling the engine. The sealant will prevent oil leaks from occurring where the ends of the rope seals meet.
