21 stud oil pan question?

In the pass side front of the pan is what looks to me like a bafffle or maybe an overflow. The oil level on the stick is about an 1/8th inch above the full mark and there is oil leaking out of this spot. Is this a overflow or do I need to pull the pan and look into this further. My experence with flatheads is minimal so any knowledge will be appreciated.
 
That is a crankcase gas/vapor road vent. If you overfill, I'd expect some oil weepage there as in other places. 8^)

Jack E/NJ
 
As was said, that is a crank case breather, But I don't think 1/8 over full is going to drip out of there. Two things will cause this, the pan gasket can be sucked in on the inside or, there is a pipe about 1-1/4in. in dia. about 6in. long that is underneath the front of the intake manifold that is lined right up with that breather. That pipe could be left out. What is the history of the engine? Has it been apart lately? Walt
 
A vented pan on an early block, I found, will blow oil all the time. I put a vented pan on a '33 block and that was my problem. Had to drop the pan and weld the vent closed.
 
A vented pan on an early block, I found, will blow oil all the time. I put a vented pan on a '33 block and that was my problem. Had to drop the pan and weld the vent closed.
The 33 engine didn't have that vent in the block and pan gasket was differant that the 35. SO, if you used a 33 pan gasket and a 35 oil pan the back of the hole was wide open to the crank case and will throw oil right out the 35 vent. Walt
 
Walt,

The vent tube you talk about if it is not install the oil in the valley will fall stright down to the oil pan and leak out of the baffle? The motor I put in the truck was a fresh sleeve rebuild that my grandpa had stashed away for 20 yrs. I looked at the motor I pulled and I did see the vent tube. I did not look or know about vented blocks vs. non during the install, I guess ill pull the intake and inspect. Thanks
 
If it has the wrong oil pan gasket, as Walt mentioned, you would need to drop the pan to fix that. I don't know of any way to check which gasket has been used unless you do drop the oil pan.
 
I'm almost positive that it has the correct oil pan gasket on it, the kit came with gaskets for two style pans and the ones I have left over aren't the right ones.
 
if you put a vented pan on a none vented block you will get an oil leak out of the vent no mater whitch gasket you use.because the early none vented block does not have the metel casted on the block & the vented pan cant seal .if you don,t want to remove the pan fill the vent with some kind of oil proof meteral.
 
Bedford, you haven't said what year engine your working on. 35 was the first year that they used the oil pan breather. That engine must have that tube under the front of the intake manifold, If it's not there oil will blow down that hole where the tube goes and drip right out that pan vent.The 34 and earlier engine didn't have that breather or tube. SO, pull the intake and see if the tube is there, if it's a 35 or later engine and does'nt have the tube you'll see a hole in there about the size of a quarter the the tube sticks into. The tube is about 6in. long and sticks into that hole and the top of the tube is about 1/8in. below the intake gasket surface. Let us know how you make out. Walt
 
You could also pull your fuel pump stand and see if you have a circular raised socket in the casting around the fuel pump pushrod bushing . If yes you have a vented block as this is what the breather pipe slips into . If the casting is open around the fuel pump push rod bushing you have a non-vented block . Walt's info is correct - this is just another way of checking .
 
Ok some of you have been helping me with an oil leak and this is what I found today. The baffle in the oil pan has a slit cut clean down to the bottom, why I have no idea. My question now is do I weld This slit up to the top, or was this slit just carried down more for some reason at some point in time and why? Thanks oil pan 002.JPG
 
First pic is a 35 oil pan and it has the same slot as yours = not modified . Pic 2 is a vented block and pic 3 is a non-vented block . Did you ever figure out if you have a vented or a non-vented block ? You have numerous options pointed out above but it can be simply checked by looking under your fuel pump stand . See the big raised boss the pipe slips into on the vented block . Notice the non-vented block is WAAAY different there This is real obvious by simply lifting the fuel pump stand up . If you have a non vented block the vent will leak badly for reasons already pointed out by others .
 

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If you were looking at the pan rails on those engines above, you would see a offset to the inside of the block that corresponds with the offset on your pan and is sealed with a gasket. Pic three above, an early engine without the front oil breather tube would not have that offset in the pan rail and as a result your pan would have a exposed hole in it at pan rail level toward the inside of the engine.
 
I pulled the intake and the vent tube is there, so I attempted to pull the pan but couldn't get it off, I had the front end out and trans un bolted and motor jacked up till it was hittting the fire wall but I did get it up enough to see I had the wrong gasket. Called the neighbor he had bought a wrong set for his 33 so he gave them to me I put em on and its drying now. So I'll keep my fingers crossed. Thanks for all of your guys knowledge!
 
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