R Model Air Cleaner Question

[Mr Black]

Hi, I have a small hose coming off the air cleaner housing of my ’85 R Model. From memory, I would say it is about 8-10mm in diameter and comes off the side of the air cleaner housing. I am fabricating some new air intake parts but I forgot to check what the hose was for last time I was at the truck (which is parked off-site). Would anyone happen to know what it is for as I am trying to save a trip back to the truck (which is in another city) to check. I am temporarily installing a remotely located air cleaner while work is being done on the truck and I am hoping this hose can be ignored and temporarily blocked. I have a similar outlet hose on another truck and it is just a sensor for testing the air but I have never paid any attention to what the hose is for on the R Model.

Any ideas? I am hoping not to have to make the trip out to the truck to check!!!

[David]

Probably a Filter Minder®. Is there one in the dash?

[Lmackattack]

Air restriction gauge most likely...

[Mr Black]

Air restriction gauge most likely...

Thanks gents, I don't know if I have a guage/Filter Minder as the truck has been parked up since I bought it and all I have been doing is stripping it for restoration - can't recall what guages it has. I suspected it would be some sort of sensor so I wouldn't imagine it is something I have to re-plumb while I have the temporary remote intakes fitted. Just thought I would check if anyone with R Model experience is aware of anything of this type that could be more important.

[bbigrig]

Sounds like a filter minder but.......

If it looks like an air line (1/4 nylon) it could be your truck is equipped with an air cylinder on the inside of the air cylinder that controls an inside/outside air selector gate. Most Macks in Canada were ordered with this option and the upper dash panel would have had an air switch on it. It is a gate that either selects to suck in air from the normal outside "hat" or "snorkel" we are all familiar with or it sucked air from a short large hose that sucked from under the hood. It may not be an inside outside air system but thought I would throw that in just in case.