Take oil filler cap off,car stalls(non-dsm)

[pitbull419]

This is not a dsm which is why i posted in the hangout.
I figured this was the best place.
So my neighbor has a 96 chevy lumina.
It has been overheating.I was thinking blown headgasket.
Untill I took off the oil filler cap while it was running and it shut off.
Now im thinking maybe a bad valve or valve seal.
What do you guys think???

Thanks in advance

 

[VelocitàPaola]

I think you're causing a giant vacuum leak via the PCV system when you take the oil cap off; thus causing the car to stall...

 

[schoffs4]

Intake gasket very common ,it will suck the block in a vaccume burn lots of oil, coolant in oil. pcv can cause it too but not common. Block the pcv off start the car remove the cap and place you hand over the hole if it sucks in... INTAKE GASKET I do 2-3 a month for the same problem [ 3.1 and newer 3.4]

 

[Defiant]

And somehow, they still keep selling Chevys.

 

[pitbull419]

This is a 97 3.1 not a 96 sorry.I think there the same anyways.\
It had me kind of stumped because everyother car i have takin the oil cap off while it was running it never shut off.Idled a little low(almost not enought to tell the difference) but never shut off. I always take the cap off on my race cars to make sure oil is getting to the head.
Where is the pcv valve on these cars.
newer chevys are like a honda to me.Un explored teritory

 

[pitbull419]

When i take the oil cap off and put my hand over the hole i feel it sucking in.
This is without blocking the pcv valve off.

 

[VelocitàPaola]

When i take the oil cap off and put my hand over the hole i feel it sucking in.
This is without blocking the pcv valve off.

That sounds about right... the crankcase is supposed to be under vacuum.

 

[pitbull419]

I dont under stand what you mean.
Do you mean its supposed to suck in or its supposed to shut off?
When i take it off on other cars they dont shut off.
Since your a mod was this the correct place to post this?

 

[schoffs4]

Take out PCV and block it off for test if it still sucks you hand in its your intake gasket SEE IT ALL THE TIME IN MY SHOP

They have crappy gaskets plastic with o ring type built in seal they crack {they all do] and cause one or more of the intake ports to suck the intake valley in to a vaccume. they also leak coolant externally and internally [ coolant at corners of intake and coolant in oil] do the test stated.

 

[pitbull419]

How do i get to the pcv?
It looks to be under the intake plenium.\

 

[pitbull419]

So i tryed the pcv valve thing.
If i did it correct i dont know.
I pulled the hose off the pcv valve and the hose was sucking in.Is that what you were talking about.\


Also when i step on the gas and hold it the car does a quick rev down then back to where im holding the pedal???????

 

[schoffs4]

You have to block off where it sucking in[PCV} then check your oil fill hole for vaccume

 

[Bmxr152]

Some cars have vaccume throught the crankcase. I know my mustang cobra does, if you remove the oil fill cap while running it will die.

 

[pitbull419]

Like this????

 

[pitbull419]

Yes I also discovered there is water coming out the exhaust.

 

[schoffs4]

block off the vac supply to the pcv then ck for vaccume this car shouldnt suck in

 

[pitbull419]

So block off the vaccume line that connects to the pcv?
And leave the pcv open?

 

[pitbull419]

Blocked of the vacume source to the pcv.
It doesnt suck in.It blows out a little.

Now the head is completely filling up with water.
I have videos.If anybody would like to take a look and maybe give me an idea.

 

[pitbull419]

Also has tons of white smoke coming out.
Im thinking a completely destroyed head gasket or cracked head

 

[pitbull419]

Im in the middle of changing the intake gasket.Im going to hope thats what it is.
This cars were built really shity.
Was chevy serious?I have to take the push rods out to change an intake gasket???
Any body know where there is a step by step on the internet with all the specs and stuff?
No shop or the library around here has a haynes or chilton for this car.

 

[schoffs4]

becarefull the intake and exaust push rods are different one 1/4 in longer

 

[schoffs4]

I havn't seen a intake gasket cause white smoke yet [dosent look good] head gasket I've done 2 3.1 intake gaskets this week

 

[pitbull419]

I kept the pusrods seperated and put them back where they were.I build mustangs as well so I know.
I think the smoke is because of all the water that ended up in the oil.
This was not a leak more like a raging river.It was bad.
The gasket around the water passage was destroyed.
Also if I may ask how much do you usually charge to do the intake gaskets on one of these cars?
Also Chevy If you see this who ever planed out these cars is an idiot and should have there head checked.

 

[turboblack2door]

my friends 97 mx6 v6 does the same thing