Dorman oil line block-off plate kits are used to seal off or cover a port in the engine's oil system, often when an oil cooler or another component is removed or not being used. Kits include a precision-machined plate, necessary gaskets, O-rings, and hardware to create a reliable, leak-free seal. These are direct replacements for original equipment parts that are missing or damaged, and they're made from durable, corrosion-resistant materials engineered to withstand high temperatures and engine fluids, ensuring a long service life.