When i purchased my used 1990 240 about 6 years ago the aluminum preheat hose was not there. I never gave it a second thought until i saw it in every car at the pick & pull. it seems from what I've been reading that it is not necessary and can actually cause problems if the thermostat isn't working.
should i close off the plastic pipe coming from the air box or where the hose would attach on the other end (not sure where this is)?

thanks