What is this called and what is it for

Hello, I'm Danny.

That is called the PCV (positive crankcase ventilation) hose. It takes the gases and fumes that pass by the combustion process and send those gases back through the intake manifold assembly to the engine to be re-burnt. This is done for reduced air pollution into the environment.Only gases and fumes pass through the hose (no liquids) So if there is a minor kink I so no damage being done. Just try your best to get the kink out and you'll be okay. Hope this helps and thanks for using 2CarPros.

This is should have a valve on the end closest to the valve cover. It is called the PCV (positive crankcase ventilation) valve. Basically it allows gases that are produced by the engine to be reused by the engine and not omitted to the atmosphere.

However, that line does look pretty thick so I just want to make sure you still have a PCV installed in the line. Basically it is a check valve and only allows gases out and not back in the engine. If they come back in, it can cause performance issues.

the original one did not have a valve it was just a hose.

Then you are looking at the fresh air side of the system. One hose comes from the air cleaner to the inlet, then on the other valve cover will be the valve and hose that takes the air out and to the intake to burn off any of the gasses that are in the engine crankcase.