What is a PCV Valve Hose made of? Can any rubber hose replace it? Like the rubber hoses used for gas lines in lawnmowers? Does it need to be made of some type of plastic? From what I understand, the hose just moves gases developed in the cranckcase from blowby to balance out the pressure in the cranckcase right? So considering it is only gases that the hose is moving, can it be replaced with a rubber hose? I would much rather spend $5 for a rubber hose than $36 for the actual part (part number 6758 on fordparts.com). However, I am curious to know if the gases will eat away the rubber material or not (if I need the actual ford part or not).
Yes, you could use any fuel and oil resistant hose. They are typically made of silicone, polyurethane or rubber. This will ensure longevity of the replaced hose. Have a look at silicone automotive hoses.
One thing to consider is, on many modern systems the hoses are molded to a particular shape to clear surrounding components in the bay. If this is the case, you'll be better off using the correct part to avoid kinking or straining the universal hose. If its quite simple, you can make sure the hose is secure and less prone to making contact with other parts such as belts, manifolds, etc. Of course, use hose clamps at each end.
The part you use should withstand high temperatures and must not collapse under vacuum. I think if you use garden hose, it will just collapse and also melt down.
The only hands on experience I have is changing the PCV hose with a silicone one in a jaguar s-type v6 3.0. It worked fine there, but that doesnt mean that you will have similar results.
You can get reinforced vacuum silicone hoses cheaper than your garden hose at aliexpress for example. (you need to know what size/length you need)
I found a reference from Motor Week saying NOT to use fuel line or vacuum hose as a substitute for PCV hose. Quote:
The vacuum hose won’t stand up to the oil that comes through this [PCV] system. The fuel hose is designed for internal pressure. It will collapse under the vacuum of the PCV system. PCV hose is designed specifically so it won’t collapse. So insist on PCV hose, never fuel hose or vacuum hose.