[ericwy]

The 400 in my TA has had some oil leaks since is was rebuilt in 2004.
Nothing major just some annoying drips on the floor.
Over time I have tracked each one down and fixed them. Valve covers,
oil pressure sending unit, oil pan gasket, PVC fresh air tube grommet, etc...

But one has continued and I had pretty much figured it was a leaking rear
seal that would need to taken care of "eventually."

So, just poking around under the hood over the weekend I happen to shine
a flashlight under the intake manifold and noticed about an 1/8" deep puddle
of oil on top of the lifter valley cover. Its located roughly above the #5 and
#6 cylinders. Could this be oil from the PVC valve/grommet that goes through
the valley cover? Any other ways oil could get on top like this?

[67 Lamnas]

Originally Posted by ericwy

The 400 in my TA has had some oil leaks since is was rebuilt in 2004.
Nothing major just some annoying drips on the floor.
Over time I have tracked each one down and fixed them. Valve covers,
oil pressure sending unit, oil pan gasket, PVC fresh air tube grommet, etc...

But one has continued and I had pretty much figured it was a leaking rear
seal that would need to taken care of "eventually."

So, just poking around under the hood over the weekend I happen to shine
a flashlight under the intake manifold and noticed about an 1/8" deep puddle
of oil on top of the lifter valley cover. Its located roughly above the #5 and
#6 cylinders. Could this be oil from the PVC valve/grommet that goes through
the valley cover? Any other ways oil could get on top like this?

Could be the grommet or it could be the valley pan gasket also...........

[Slick 50]

Could be the bolts that hold the valley cover on or a valve cover or the PVC as mentioned above. Sounds like a bunch of leaks, is the PVC working properly?

[ericwy]

Originally Posted by Slick 50

Could be the bolts that hold the valley cover on or a valve cover or the PVC as mentioned above. Sounds like a bunch of leaks, is the PVC working properly?

PVC seems to be working, engine runs great and you can hear/feel the little valve
doing its job, allthough the grommet fits pretty loose in the valley cover.

I never thought to check the valley pan gasket, just figured since it was on top
of the engine how could oil leak there? The shop that built the engine did goof
up installing the intake manifold by using the wrong intake gasket. (I have a 1968
non-EGR Pontiac manifold) Maybe they messed up the valley pan gasket in the process?

I would guess that the oil collects in the low areas of the valley cover until it either
sloshes out or gets blown out.

Guess I will mop it up with some rags and them watch to see how quick it returns....

[wheelspin]

Intake gaskets can leak oil from the two head casting open areas, located on each side of the exhaust X-over. The oil will run down into the valley pan area, along the edge of the seam, collect around the distributor base, and finally find it's way to the ground via the bellhousing.

Les

[Brian Baker]

Time to pull the intake manifold and inspect. Could be from the aforementioned intake gaskets...could be oil getting pushed past the valley cover gasket/bolts/PCV grommet from excessive crankcase pressure as well. What kind of mods do you have on the car? Keep in mind any mod that increases cylinder pressure, you have to also vent it on the other side in the crankcase.

[screamingchief]

This dilema is very common when the sealing washers for the valley cover bolts are missing or such.

They washers are basically auto trans front pump washers.

HTH.

[form406]

my valley grommet although very old is very tight, outer and inner...

[ericwy]

Originally Posted by wheelspin

Intake gaskets can leak oil from the two head casting open areas, located on each side of the exhaust X-over. The oil will run down into the valley pan area, along the edge of the seam, collect around the distributor base, and finally find it's way to the ground via the bellhousing.

Les

You must have stopped by and inspected my car because that is exactly what I am
seeing. I had just assumed that oil was also leaking from the distributer mount hole
and running down as you described.

[David Jones]

Find the leak, before you take anything apart. Wipe it off and run it or drive it for a while. I had an oil leak that I had a hard time finding. I found oil dripping off of the side of the timing cover once and traced it back up to the valley pan. I figured that the gasket at the front of the pan had started leaking. I wiped all the oil off and later found the leak at the REAR of the pan and discovered that somehow it was being blown forward. In chasing oil leaks, 1st impressions and appearances can be deceiving.

[Goathead]

Originally Posted by ericwy

You must have stopped by and inspected my car because that is exactly what I am
seeing. I had just assumed that oil was also leaking from the distributer mount hole
and running down as you described.

Finally, we found something Les is good for.....