380 Magnum Oil Leak

Tech Question


Keneuth Davis, Farmington NM, 1972 Plymouth Duster 5.9 Magnum

I have a mopar crate motor that is a 380 magnum based on the 360. I have a evil oil leak between pan and gasket at front of pan at bottom center of loop. It doesnt leak on timing cover side.

I have replaced pan with a milodon and also a new mopar timing cover and it sat on engine stand over night and low and behold, leak is still there. I dont know what to do. gasket is the one piece rubber with metal impregnated sides from fel pro. This is the third try, have done it dry and with ultra black permatex and new pan and cover now and nothing stops it.

I sold the car and shipper will be here on 17th. Please help



From what you’ve written, it sounds as if you have eliminated the pan/gasket as leak source. DESPITE what you have said, I’d sure be looking hard at the timing cover seal or gasket, although I’ll admit those would be hard to create a static leak, but even the front of the pan should be above the oil level with the engine not running.

Anyway, seal and pressurize the crankcase (seal valve covers, air hose to PCV, etc.) and listen for the hiss / squirting. 10-20 Psi max or you could rupture the fuel pump diaphragm.


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