Vacuum gauge results- is this normal?
09-08-2012, 06:53 PM
#1
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Vacuum gauge results- is this normal?
Bought a vacuum gauge and wanted to know if these results looks okay on a 93 LT1. Intake manifold leak was just repaired last week. Noticed the two ports have different values but both are solid and needle is steady. Are the the correct spots to measure vacuum leaks?
Hooked gauge up to passenger side where the fuel pressure regulator hooks up to the intake.
Then I tried hooking it to the drivers side port on the intake above the Pcv valve
Sent from my PC36100 using Tapatalk 2
Hooked gauge up to passenger side where the fuel pressure regulator hooks up to the intake.
Then I tried hooking it to the drivers side port on the intake above the Pcv valve
Sent from my PC36100 using Tapatalk 2
Last edited by Injuneer; 09-08-2012 at 07:30 PM. Reason: When posing multiple pictures, hit "enter" after the [/img] tag, so they don't spread across the post.
09-23-2012, 05:52 PM
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09-23-2012, 08:47 PM
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Re: Vacuum gauge results- is this normal?
The crankcase/lifter valley can be under positive pressure if the PCV valve is not working, or if you have excessive piston ring blowby. The intake manifold seal that leaks oil is between the bottom surface of the manifold and the rear wall of the block. Has nothing to do with intake manifold vacuum except if the PCV system is pulling a vacuum on the crankcase.
09-26-2012, 04:23 PM
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Re: Vacuum gauge results- is this normal?
The crankcase/lifter valley can be under positive pressure if the PCV valve is not working, or if you have excessive piston ring blowby. The intake manifold seal that leaks oil is between the bottom surface of the manifold and the rear wall of the block. Has nothing to do with intake manifold vacuum except if the PCV system is pulling a vacuum on the crankcase.
Is the underside of the intake manifold where the lifters are located under that much positive pressure where it causes the rear intake manifold to leak tons of oil?
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