Hello everyone,
I have a disagreement among mechanics. Over a year ago I pulled the motor, installed a number of parts including a new pan. Now have a few leaks disbursing drips to a wide area (not huge amount of oit but annoying). New pan sitting on cross member - one mechanic thinks that has killed the gasket seal. Other says caused by excessive blowby in pan. Trying to determine whether to get pan off cross member and put on new gasket or save my money to eventually replace motor. Thoughts? Thanks.

Something is not right that the pan is sitting on cross member. What pan? What year block? Last 8 birds I worked on had a minimum of 3/4" inch clearance with factory pan. I have a milodon pan on my 68 with at least 1" clearance with regular rubber mounts.
Someone did not do a proper job on installing the oil pan, should not be any leaks. If you had all the supposed blow by it would be pushing oil out of various other places as well.

Found out after buying the bird that the 400 that was supposed to be in it was a '65 389. Other places as in where? Thanks!

Like out the breather and through the pcv valve. Bottom end isn't a pressure vessel it's open to ambient air, excessive blowby will release through the crankcase ventilation, unless it's not functioning. Never the less it shouldn't be blowing oil out of the pan seal if installed correctly.
389 and 400 have the same basic block dimensions should fit without touching cross member, unless it's a way different pan.

Just my opinion, I'm not an expert.

I have no idea. Not very good with mechanical end, but it sounded logical that jarring, etc could cause the gasket to fail. Forot to answer Big Chief`s question. It is a Milodon pan that the company swears should work. Part of the problem may be less clearance for the 65 motor when put in a 69? Thanks

I had excessive blow-by in my professionally rebuilt 455 until the rings seated. I blew out my rear oil pan seal shortly after putting the engine in the car. Pulled the engine back out and installed BOP Engineering's new 1-piece steel reinforced oil pan gasket. No problems since.

Okay, I guess my next question is whether I can bend the Milodon pan some way to try and fix. Thoughts? Put something on the crossmember and lower the motor down tobend and get some clearance? At the risk of forever shaming my name on Firstgen, if I have replaced pan, aircleaner, intake, valve covers, etc do I even have a PVC valve anymore? Thanks

Having no oil pan to crossmember clearance is a common issue with these cars. Several of us have just added shims (spacers) in the motor mounts to raise the engine a little. Works fine, just be sure to check your air cleaner stud to hood clearance!

Ok. Confirmed I don`t have a PVC valve. Still think I need to narrow down the source of leak then tackle the pan gasket if that is the problem. If that is the case then I will just have to modify the pan while it is off. Thanks for the input!

Football nut
Where in AZ?
I'm in Gilbert maybe I can check out whats going on.

Hello Big Chief,
I live south of Tucson in Vail. It would be great to meet up, but I hardly ever get up your way to the big city. Thanks for the help, just have to make sure I pinpoint the source of the leak and go from there. I just put in disc brakes and the booster really makes things cramped on that side of the engine bay if I try to just lift the motor to pull the pan.

Problem with doing it in the car is its almost impossible to keep everything clean to seal up perfectly.

I recall working on a few older cars where the oils pans always seemed to have "dents" in them at various locations....always assumed these dents were from hitting road debris/thrown rocks/etc...any chance some of those dents were "precision hammer wacks" to give those pans a little clearance here and there?

If it is for clearance, the PO of my '69 also need "clearance" at the left passenger foor well and the gas tank. And by coincidence the sub-frame cross member was packed tight with gravel.

I have the same issue with a Butler built 455 I inherited with a vehicle purchase. After 3 weeks of hair pulling, bought a black light and dye after replacing valve cover gaskets (leak) and oil wet breather and oil leak from stock pan. Turns out the genius installed the wrong dipstick and tube and filled it up with oil to the full line...

That full line was 9 quarts.

I'd confirm oil capacity, invest in a 12v blacklight, dump some dye in, and track down source. No or clogged pcv can cause blowby..but the pan should have a fingers clearance. lf not, likely the pan buckled and causing the issue.

Before I used tracker dye...I used purple stuff degreaser and pressure washed block with hot water.

Turns out the 3 quarts extra was seeping past the pan gasket.

Man, that previous owner must have been a real DIPSTICK, eh Banshee? Reminds me of a soldier of mines wife in Germany. We were away from homestation and she decided to check the oil level in her Opal straight-six engine. She was never taught how to use a dipstick and she assumed oil needed to be added until one could see oil through the valve cover oil cap........I think she stopped at around 10 quarts realizing something wasn't right.

If you don't have a pcv valve that may be the cause. Our 400s have a pcv valve in the valley pan near the front on the right. Your 389 should have a pcv valve at the rear on the passenger side near number 8 cylinder and vent into the manifold in front of the carb.
But, I've been wrong before.