Thread: losing oil on start up

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Ok, i have a 400 chevy and when i start it up it's hard to start at first, usually starts right up. Also when i start it up now it's leaking oil down the oil filter, lots of it too. But after it starts the leaking stops and it drives and runs fine. Also on the start up there seems to be grinding coming from the starter area. I changed the starter thinking it was the problem on the grinding, but still does it. Put shims on it too so i'm pretty sure it's not contacting the flywheel. No idea on why the oil lose now, it happened all of sudden. Drove it to my friends, and it didn't do it drove it home and went out an hour later to move the jeep and i heard the grinding but no leaking....after a few more starts the oil started leaking. Any ideas or suggestion?

As far as that oil leak, does the oil come from the crank-case vent-hose or through intake manifold?

If you have this answer, it will help looking in the right direction.

it's coming out around the oil filter it self, no where else. I just pulled the filter to check the seal and it looks new, which that oil filter is still pretty new, just 3 months old. I looked at the block and didn't see anything unusual like a crack or anything.

I appologize, For some reason I assumed airfilter.

You have a oil-pressure gauge?
It might be your oilpump pressure relief-spring.

-oilpump builts up to much pressure.
-this is even worse when oil is cold (start-up)
-it will be forced out where resistence is least.
-when engine runs for a little, oil heats up and loses some of its "thickness" so oil gets pumped around easier.

Grinding noise comes more then likely from your pump too.
If this is it it's fairly cheap fix, just hope you can drop the pan with motor in vehicle.


It's a guess, but worth to look into.
Hope it helps a little.

it does help, i have plenty of clearence to drop the pan, in a Jeep Cj with plenty of lift to clear the axle. I'll probably do that tomorrow, the pan gasket needed changed anyway.