# What is this thing above vaccum manifold?

**URL:** <https://community.cartalk.com/t/what-is-this-thing-above-vaccum-manifold/43517>\
**Category:** Maintenance/Repairs\
**Tags:** pontiac, lemans\
**Created:** [January 31, 2010, 12:18am UTC](https://community.cartalk.com/t/what-is-this-thing-above-vaccum-manifold/43517 "2010-01-31T00:18:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![fanghuzhai](https://avatars.discourse-cdn.com/v4/letter/f/d78d45/32.png) [@fanghuzhai](https://community.cartalk.com/u/fanghuzhai)\
**Post date:** [January 31, 2010, 12:18am UTC](https://community.cartalk.com/t/what-is-this-thing-above-vaccum-manifold/43517/1 "2010-01-31T00:18:47Z")

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What is this round stuff with the black tube A? A is connect to something attached to the vacuum manifold, but when I pulled A off the round thing, there is no sucking. Black tube B could not be pulled off. I am looking for a place to hook up the vacuum gauge.  
  
  
  
  
  
 [http://www…316791507/](http://www.flickr.com/photos/marthacside/4316791507/)

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**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\
**Post date:** [January 31, 2010, 12:38am UTC](https://community.cartalk.com/t/what-is-this-thing-above-vaccum-manifold/43517/2 "2010-01-31T00:38:53Z")

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That is the EGR valve. The vacuum hose to that valve has only partial vacuum, and only at the times that the EGR valve should be open. It’s not a good place at all to check engine vacuum.

And, it’s not called a vacuum manifold. It’s the intake manifold.

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**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\
**Post date:** [January 31, 2010, 12:47am UTC](https://community.cartalk.com/t/what-is-this-thing-above-vaccum-manifold/43517/3 "2010-01-31T00:47:49Z")

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I’m assuming that you mean ‘intake manifold’ instead of vacuum manifold. The round item connected to tube A should be the EGR valve, and vacuum through tube A when the engine is sped up and under load. Tube A has ‘port’ vacuum, and your looking for manifold vacuum.

I cannot tell by the photo if tube B is port vacuum or manifold vacuum. It depends on what is connected to the other end. A good source for manifold vacuum is any small tubes connected to the brake booster vacuum line. Many cars of this era had a connector that had a few small branches of vacuum line and the big brake booster vacuum line attached. Follow the brake booster line and see where it connects to the engine.