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On the bottom of my air cleaner neck is the circular port pictured below. Mines not connected to anything. In another thread I saw someone's had a hose connected to it but couldn't tell where it was going. On the top side of this port is a mechanical device that runs on vacuum to the top of the air cleaner. It moves a block off plate to open the bottom port or open the end of the air cleaner neck. Where does this hose go and why is mine not connected to anything.
Shop manuals on CD are on the way but I'm trying to get some things hauled beforehand.
It originally went to a shroud around the exhaust manifold - the vacuum switch mounted in the air cleaner is thermally-actuated, and moves the actuator there to draw warm or cold air as needed (warm for cold-start, cold once warmed up). The bottom port connects via a preheater hose to the exhaust heat shroud, and the square front port connects to an air intake attached to the core support.
If your exhaust heat shroud is still there, the preheater hoses are cheap and readily available. If the shroud is missing, good luck finding one - no one reproduces them, and they're usually missing long before a vehicle makes it to the junk yard. May have to fab one up yourself if you want it to function as designed.
Ah, that explains the rusted out exhaust looking thing I pulled out of the engine compartment around the same time. PO had pulled what was left of it off and left it for me to figure out I guess.
I guess I'll just pull the vac hose from the therm switch so that it always stays cold air. Thanks
You could do that, or leave the vacuum hooked up and just let it switch between under-hood air and air from the hose that goes to the core support. The former will be somewhat warmer than the latter, even if not as much so as in the original configuration.
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