I just picked up a '94 855t, with the head off. I was looking through the pile of parts, and the car has an odd vacuum rounting that I've only seen one other time, despite having owned multiple turbo 850s.

There is a metal tube, in sort of a "U" shape, that bolts to the top of the valve cover, under the plug wire cover. When mounted, the two ends stick out between the distributor cap and the cam sensor. At least that's the way I remember it. Like I said, I've only seen it on one other car, and I'm pretty sure it had vacuum lines routed to each end of it.

So, questions...

Is this in fact for vacuum routing? What purpose does it serve? The only thing I can figure is that it bolts to the head to act as a warmer, but why?

 

Search a little bit

https://volvoforums.com/forum/showth...be+valve+cover

 

Sorry. My 70 hour work week doesn't give me much time to read through every thread that doesn't answer my question, but I'll try and refrain from asking any question that might have been asked at some point in the past.