Lower intake sucking oil? Is it possible to test?

98BLKGT · Jun 19, 2007

Sometimes my car will blow a little smoke after hard driving. It also has a bad idle when cold and backfire into the intake if I drive it cold, but just fine when it warms up after 3-4 mins.
Does this sound like a vac leak in the lower intake manifold by the heads?
Is it possible to test this somehow without taking it all apart?

vristang · Jun 19, 2007

98BLKGT said:
Sometimes my car will blow a little smoke after hard driving. It also has a bad idle when cold and backfire into the intake if I drive it cold, but just fine when it warms up after 3-4 mins.
Does this sound like a vac leak in the lower intake manifold by the heads?
Is it possible to test this somehow without taking it all apart?

I have found this type of vac leak before by taking the pcv line off the upper intake, and putting a vac gauge on the pcv line. If setup correctly, you will be measuring the pressure/vac in the crankcase.

If there is no vac leak via the head/intake gasket, then you will see pressure in the crankcase.
If there is a vac leak via the head/intake gasket, then you will have near manifold vac in the crankcase.

It is also advisable to pull the diagnostice codes.

Hope that helps,
jason

98BLKGT · Jun 19, 2007

vristang said:
I have found this type of vac leak before by taking the pcv line off the upper intake, and putting a vac gauge on the pcv line. If setup correctly, you will be measuring the pressure/vac in the crankcase.

If there is no vac leak via the head/intake gasket, then you will see pressure in the crankcase.
If there is a vac leak via the head/intake gasket, then you will have near manifold vac in the crankcase.

It is also advisable to pull the diagnostice codes.

Hope that helps,
jason

Wow, thats perfect. I never thought of this. Here's the thing. One of the things I tried was unpluging the PCV hose and blocking off the intake side to look for vac leaks. I also unpluged the hose from the TB to the filler neck.
I found the the hose from the filler neck had pressure comming out of it but no pressure comming out of the PCV hose. This might be it.
Open to any further coments.
BTW I will pull codes with engine running. Nothing really with the key on test.

vristang · Jun 20, 2007

98BLKGT said:
Wow, thats perfect. I never thought of this.

I stumbled on this 'test' out of an act of desperation.
I didn't know what else to try..

98BLKGT said:
I found the the hose from the filler neck had pressure comming out of it but no pressure comming out of the PCV hose. This might be it..

You may consider checking the pcv and the pcv screen. Sometimes they get plugged up and block flow...

let us know,
jason

Lower intake sucking oil? Is it possible to test?

98BLKGT

vristang

98BLKGT

vristang

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