Where is this oil leak coming from?

[Ak. Mal]

Seriously, I gave up trying to fix the oil leaks back in May only to have a very mild summer of driving time slap me in the face.

I reinstalled the header this week. That header gasket is brand new, only been around the block once. The valve cover gaskets were replaced in May along with a new oil pan and gasket. Along the bottom of the valve covers I can't manage to find any signs of oil. But from underneath the #7 header tube has oil all around the bottom of it and it has dripped onto the collector below.

 

[mrvette]

Did you check really good with a good high powered flashlight...along the back/rear of the 'china wall' on the intake manifold....that flange around the oil pressure gauge and the dizzy mounting.....if that block skirt/bellhousing is wet....well oil gauge, dizzy or rear china wall leak....

china wall leak is not all THAT bad to fix but a PIA...I have a trick for a easy route if it's that part....

:smash:

 

[pcf_mark]

If it is not coming from up top like Mr Vette pointed out then it could be the oil filter gasket or filter is not tight enough. There is also a plug above the oil filter where the early cars pick up oil pressure. It has a square plug in your photo - that could be leaking.

 

[TimAT]

Clean everything up with brake clean or alcohol- get it all really clean. Then dust it with baby powder after you dry everything. The baby powder will point at the source of the leak like a lightning bolt. And the baby powder will wash off after you're done.

 

[Red]

I had a leak from under my twist on oil filler cap. The gasket wasn't sealing well, but it went undetected while I was looking for other sources in the same location as you. You can always put a dye in your oil that will show up under a black light. This will help locate the source, but cost alot more than the baby powder technique. Good luck!

 

[mrvette]

Clean everything up with brake clean or alcohol- get it all really clean. Then dust it with baby powder after you dry everything. The baby powder will point at the source of the leak like a lightning bolt. And the baby powder will wash off after you're done.

I bet the line mechanics were laughing their asses off at you with BABY powder in your tool box.....

:devil::yahoo::harhar::trumpet:

 

[TimAT]

Yep, they laughed- at first. Then they figured it out. No more laughs.

We used Magnaflux developer by the case. Handy rattle can stuff, but won't wash off. Works for fuel, oil, and water. And you don't want to spend the $$ for it. Not cheap. You can get baby powder by the trainload for what a can of that developer sells for. Last I checked, a 12oz can of developer was around $25. What's a bottle of baby powder? $3?

 

[Red]

You make me feel bad, I paid $15 for a four ounce bottle, while baby powder is $1 all day long at the Dollar Store. I'm learning good stuff all the time here on Vettemod. :thumbs:

 

[BlackRat]

Red,

I had a similar issue. Mine only leaked when I was driving. It would si and idle all day long and not drip a drop! It did turn out to be a small leak at the back of my intake manifold. Only came out during really high pressure. As others have said, wipe the china wall area really good and then watch it. I did not try the baby powder method but I have that one stored in memory now!!! Thanks TimAT!

Wade

 

[mrvette]

Red,

I had a similar issue. Mine only leaked when I was driving. It would si and idle all day long and not drip a drop! It did turn out to be a small leak at the back of my intake manifold. Only came out during really high pressure. As others have said, wipe the china wall area really good and then watch it. I did not try the baby powder method but I have that one stored in memory now!!! Thanks TimAT!

Wade

Kevin, from Missouri on here, is using a airpump to evacuate the crank and put it under suction at about 5+"? of vacuum....that is with engine running at speed too.....I did the same thing once, but the stinky discharge from the pump made it untennable....

 

[damoroso]

Ak. Mal,

I noticed in the pic you posted, it looks like you have aftermarket chrome valve covers. If that's the case, those are usually thin stamped steel and the bolt holes have a tendancy to bend a bit. If you find the leak is coming from the vavle cover (I suspect it is), pull the cover, check to make sure they're flat and straight. If you need to "fix" the bolt holes, use a hammer and something flat to make the holes flat again.