1998 S70 Trivia: Can you identify this small tube?

[Rondo]

Knew my response was dumb, but I've learned to seek out simple answers first. Glad someone could help.

[BrianD]

No it wasn't a bad idea -- the hose had to come from somewhere that wasn't obvious! But this Michigan winter is giving me lots of chances to test out the windshield-fluid-delivery-system, so I was sure that wasn't it.

Thanks,

Brian

[xHeart]

Ding ding ding! Great team work, thanks.

It is the same line diagnosed in the post linked to above by xHeart, and suggested by others:
https://www.matthewsvolvosite.com/forums ... 0&p=245663
I should have been more thorough in searching past threads.

Both ends connect to the air filter box. One along the firewall-side, near the top, and the other on the front bottom corner, on the passenger (right) side. I gather this second connection is the "vacuum tree." In that spot I found a busted elbow connector, but the connector at the other end is just missing.

I think I have enough info to get the parts and fix it, but if anyone has any pointers or other thoughts, they'd be more than welcome!

The tube will slip off the elbow often, especially when you tinker in the area.
The engine will run at a higher rpm, bit noisy.
I applied a thin coat of gorilla at each end for adhesion.

[abscate]

I've never stolen a coat from a gorilla...sounds dangerous, Shirley

[misha]

...Both ends connect to the air filter box.

If both ends connects to air filter housing...that's the one.It goes from the front bottom of the air filter housing to the upper back of it.

If it's not that line....than...it looks like a pcv system vacuum line which goes from alternator & power steering area(the nipple from left side of the intake manifold )to a flame trap housing nipple.

[BrianD]

The fix is done! As predicted, it's idling 100~150 rpm lower. And perhaps I'm just excited to have it fixed, but I think I'm getting better throttle response too. Thanks all for your help!

Especially for those who might be using this thread for reference in the future:

I've attached a picture of the lower connection (referred to as the vacuum tree). I found it difficult to see but wanted a clearer view because it didn't feel like a "tree," and was able to get my cell phone down there for a photo. The other connection (up top) is shown by Greg Dawson in this thread: https://www.matthewsvolvosite.com/forums ... 0&p=245663

As for the parts, I was missing an elbow at each end and decided to replace the line anyway, since it's old enough to have a driver's license itself. I was not able to find the exact parts, but put together a nice solid connection with parts from a local specialty Volvo shop. All the fittings were really snug, so I opted to let the gorilla keep it's coat.