From what I have been told years ago, VW isolated the top of the engine from the bottom to help cool the engine. Just think about it. The air will travel the path of least resitance. With the tin or rubber seal missing and the fan getting its cooling air from inside the engine compartment while you are driving down the road,guess what the air is being drafted over first ? A big ole hot muffler !! You will get more air that way than through the little dinky vents,but its very hot air. Bye-bye heads after awhile.
Type-3s got their air through the side fender vents then around the body panels to the rear then through the big rubber bellows straight into the fan housing. They still ran hotter than a Beetle.
If you Guys want to play Russian Roulette with your type-4 powered Westys,Then leave that $40 piece of foam rubber off. They have a big muffler to help things cook down.They still run hot.
I can't stress enough it seems, That every piece of sheet metal, compartment seal is just as important as putting oil in.
Travis , I noticed that the type-3 pic you put up has a 2 barrel carb plus a turbo. I wonder if this Dude uses a stop watch to see how long his engine will stay together ? :roll: That critter has to run hot.