Main Vacuum line

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Spoolin Hooligan

Off the wagon Boost Addict
Joined
Aug 7, 2011
Messages
652
Can anyone point me in the direction of the main vacuum line on my car. And does this line feed all cylinders. Pictures or diagrams would help thanks
 
I don't think there is a "main" vacuum line in these cars, but I'm pretty new to them. Start at the vacuum block on top of the upper plenum. Then trace lines. If you are referring to the vacuum ball it is in front of the driver side front tire under the vapor cannister.
 
I don't think there is a "main" vacuum line in these cars, but I'm pretty new to them. Start at the vacuum block on top of the upper plenum. Then trace lines. If you are referring to the vacuum ball it is in front of the driver side front tire under the vapor cannister.
I'm going to use the seafoam treatment and it says make sure you pour it in the vacuum line that supplies all cylinders or I could hydrolock the engine
 
I found this
 

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I found this
no you dont want that , that is boost control and goes to the turbo compressor housing

you want the line off the vacuum block (top of engine) that feeds the pcv valve .. . last port toward firewall
 
There is no single "main" vacuum line.
Unles you count the vaccum block mounted on the top of the plenum
There are 5 different lines that run from that vacuum block.
and bear in mind there are a few "check valves" here and there as well to keep boost from applying itself to the connected device.

"feed all cylinders" is a strange term.
None of the vacuum lines "feed" any cylinders.

May I ask what exactly it is that you are trying to do or determine?
 
he stated what he was doing

the vac lines at top feed all cylinders
 
Wow..no you did not.
you must have edited your post because the email notification from you that I got said :

"he stated what he was doing ...it called reading"

That is totally uncalled for.
I was not being a smart a$S - only trying to help

I re-read all of it - and maybe I missed something - but I still did not see what he was trying to accomplish.
I see the reference to Seafoam and hydrolocking things - but puzzled since I can't see the underlying issue.
Maybe it's my computer or the thread - I don't know since I can't see anything.

You say 'the vac lines at top feed all cylinders"
What the heck does that mean exactly?
I've owned 5 LC2 engines and have yet to have one where a vacuum line "feeds" any cylinders.

If I must, I'll describe from memory what each of the 5 vacuum lines do connect to.
Or post the diagram of the entire vaccum system from my Buick Shop manual.
But trust me - it ain't "feeding" cylinders
 
You say 'the vac lines at top feed all cylinders"
What the heck does that mean exactly?
I've owned 5 LC2 engines and have yet to have one where a vacuum line "feeds" any cylinders.

If I must, I'll describe from memory what each of the 5 vacuum lines do connect to.
Or post the diagram of the entire vaccum system from my Buick Shop manual.
But trust me - it ain't "feeding" cylinders

each cylinder creates vacuum, against each vacuum line, collectively...

so if he uses one of the lines to introduce seafoam into the system he wants to make sure it will make it to all cylinders, and the answer is yes
 
I suppose the whole question could be which of the vacuum lines go straight to the plenun were someone to want to spray Seafoam into the intake system to diagnose something.
I f I don't run a vaccum block that has the extra port for the vacuum brake conversion (which is a handy port if not used for just checking vacuum) - I use the big PCV line on the driver's side, but before the check valve.
Fact is, I have a 'T" installed there for my underhood mounted vacuum gauge.
 
each cylinder creates vacuum, against each vacuum line, collectively...

so if he uses one of the lines to introduce seafoam into the system he wants to make sure it will make it to all cylinders, and the answer is yes

Aight.
As I thought.
SeaFoam away.
I hate doing that anway.
Never been a big fan of spraying stuff into my intake.
Still wondering what he is chasing
Header leak?
 
I suppose the whole question could be which of the vacuum lines go straight to the plenun were someone to want to spray Seafoam into the intake system to diagnose something..

i thought this was simple enough: "I'm going to use the seafoam treatment and it says make sure you pour it in the vacuum line that supplies all cylinders or I could hydrolock the engine"

cant really make it easier then that.
 
i thought this was simple enough: "I'm going to use the seafoam treatment and it says make sure you pour it in the vacuum line that supplies all cylinders or I could hydrolock the engine"

cant really make it easier then that.

Again - my apologies
For whatever strange reason - I don't see that on the thread.
Must be me - but I'll blame it on the computer for now
 
Again - my apologies
For whatever strange reason - I don't see that on the thread.
Must be me - but I'll blame it on the computer for now

no problem, consider it forgotten

on to the op-

im wondering what you are trying to diagnose as well?
 
i "did" and felt it was too much as even i had to go back to make sure it was there and then regrouped

you know that according to the seafoam people using it will make a lousy running car run great almost like brandy new ,.. well it cant fix headgaskets or header leaks or bad O2 or bad wires, or bad sensors, or bad ignition module or bad rings

good luck with the snake oil ..... i wouldnt put it in my lawnmower but they claim its good for that too
 
LOL - Geesh guys.
Happy Friday too by the way. :)

X2 - That's what I'm sayin'

What are we chasing?

So much of that junk and gunk on the shelves of AutoZone or wherever.
Now Seafoam has been around forever, and has it's followers...but if it is a sticky valve or a header leak. there are better, more scientifc ways to hunt that problem down rather than blowing a bunch of distillates in your intake system.
And all so often, after all the smoke has cleared, you're still in the dark.

I mean - hell - it's only a 5000 dollar engine.
I work on this principle of really respecting the car and it's pieces.
I carefully consider what corporations tell me is ok to stick down it's throat.
They don't give a damn.
 
I considered that Seafoam thing once when I had this chronic tick tick tick going on.
I was all panicked and freaky thinking I blew up my new WE4 valvetrain.

But I stopped and asked some old timer TR guys what they thought, and they all said "header leak"
Shout out to Tommy Riggs and Bweavy.

So, instead of gunking things up, pulling lines off, pouring crap down it's throat - I pulled the headers, replaced with Remflex..and viola''''sooooo smooth.

Jus sayin'
 
i "did" and felt it was too much as even i had to go back to make sure it was there and then regrouped

you know that according to the seafoam people using it will make a lousy running car run great almost like brandy new ,.. well it cant fix headgaskets or header leaks or bad O2 or bad wires, or bad sensors, or bad ignition module or bad rings

good luck with the snake oil ..... i wouldnt put it in my lawnmower but they claim its good for that too

Ever actually stop and read the fine print on the back of most of that stuff?

It's usally 'petroleum distillates" blah blah blah.

I was bored one Sunday, and started looking at the various offerings.

Now, I know, maybe it's "safe" and "good for all engines" - and maybe not.
There's more than few pieces on our intakes (IAC etc) that I don't like screwing with.
It's 80's vintage and technology.
Who know's if it's "safe" and won't mess up some of the bits n pieces.

Certain GM throttle body cleaners are.
And that's where I draw the line.
They might be a mess, with their C11 n all, but they knew what they were doing at one time
 
each cylinder creates vacuum, against each vacuum line, collectively...

so if he uses one of the lines to introduce seafoam into the system he wants to make sure it will make it to all cylinders, and the answer is yes

Would I be being a smart a$S if I recommended removing all the vacuum lines, TB cables; TV cable, removing the plenum, then drilling and tapping a special 1/8" NPT port in the plenum and label it "Seafoam Port - Feeds all cylinders"?

Don't answer that!
I know...:D

Semantics - I finally figured out what "feeding all cylinders" meant.
Common to the intake or something like that...

;)
 
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