Vantucky: what car year/model are you talking about? if its a 240 or non-turbo 740/940, take the top off the airbox, remove the air filter, and you can see the flap we're talking about in the bottom, across the 2.5" or so pipe that goes to the exhaust manifold heat riser (said tubing looks something like a clothes dryer vent hose). its this flap you want to wire closed unless you live where it gets very cold regularly and want to speed up your engine warmup time a bit, in which case, you'd want to replace the thermostat spring thing that closes it.

the little tube that sticks straight up has no function. its blocked, and I dunno what it was for.

 

Thanks for the reply. I have a NA '82 245. I gave it a hard look last night and I noticed a 2.5"-3" hose that leaves the bottom of the Airbox and curves behind the grille and goes vertical. That's all I was really able to notice from above. Does this still apply?

 

ok, those early cars have a different airbox it looks like (I"m not personally familiar with them, I'm looking in an older parts catalog). it looks like the airbox is 'on its side', and the air travels through it front to rear. the 'front' intake side has two hose fittings towards the bottom, one goes to the air snorkle thats in front of the radiator, thats the main air input, and the other goes down and towards the right side of the car, and goes to the exhaust heat riser pipe. the thermostat flap on these is considerably more complicated and is inside the front (intake) half of this box. if you remove the back and the air filter, you should see it in there.

the deal is, when these thermostats fail (and they always do), they fail OPEN, so the engine is breathing hot air off the exhaust riser. this lowers engine efficiency, and also cooks the expensive LH 'mass airflow meter' (MAF) aka 'air mass meter' AMM (two names for same thing). if you have K-jet (continuous injection), then you're still looking at lowered engine efficiency (an 82 could be either K-jet or LH-jet).