Oil Leak

[sllib]

I have a heavy oil leak coming from the front of my 351/427 Dart block. Before I started tearing off parts I thought I'd get a few opinions from the forum.
It only leaks when the engine is running. Never a drop when it's not. I actually crawled under the car when it was running and up on jack stands to try and ID the leak (not fun). I had a light and magnifying safety glasses and assumed the worst (front seal) but it appeared to be coming from the oil pan itself where it meets the block directly below the crank. I didn't think there was any pressure in the oil pan, at least not enough to cause a big leak. If I'm wrong I can drop the oil pan and RTV the low points and replace the one-piece gasket. If I'm right I will have to strip the water pump and timing cover off and replace the seal. Worst case scenario: the crank snout is bent and eating the seal, but I watched the crank being balanced at the machine shop so that possibility seems remote. As an aside I'm getting .002" run-out on the balancer but that seems minor. Any thoughts?
Bill Stradtner

[bobcowan]

A couple of thoughts. First, do you have an early model front cover with a plate for the fuyel pump? That's a common leak site.

Also, did you use thread sealant on the oil pan bolts? On some front covers, the bolt holes extend up into the case.

[sllib]

My fuel pump block-off plate is on the driver's side and couldn't cause the leak I see. It's also sealed with RTV. The oil pan has studs and I used high-temp RTV around them to seal the gaps in the pan. Still, is there enough pressure in the pan to cause a leak ONLY when it's running?
Bill

[bobcowan]

There shouldn't be much pressure at all in the pan when the engine is running; especially at idle. And if you leave the disp stick ut, the pressure would be real close to zero.

If you put silicone sealant around the studs before installing the pan, that's not likely to be a leak point. It could be, but less likely.

Try this. Clean the front of the engine really well with a good degreaser and plenty of water. Let it sit until everything is completly dry. Especially the valleys near the top of the front cover. After it's dry, sprinkle liberal amounts of corn starch, starting near the distributer, and ending near the pan.

Start the engine and warm it up. When the corn starch starts to darken, that's the oil oil leak. You might find that it starts at the block/intake seal under the thermostat housing.

[DAVID GAGNARD]

May also be the one-piece oil pan gasket...........I've not had good luck with them and had them leak...I'm back to the old school oil pan gaskets and don't have any problems......

David

[blykins]

Same here....

The one piece gaskets just don't seem to fit as well as they should. Add aftermarket oil pans with their own tolerances and aftermarket timing covers with their own tolerances and it's a stab in the dark.

To the OP:

You would be surprised to see where oil actually comes from. For instance, oil leaks that appear on the bellhousing can actually blow back from the front.

In your case, I would do what Bob suggested and see if you can find a trail. You can also buy UV dye to put in the oil. Fire it up and let it run, then use a black light and see what you get.

The oil pan shouldn't leak unless the oil level is up that high....which it shouldn't be. I would guess that it's something higher that is under pressure or under fluid level that is trickling down.

[sllib]

Thanks, guys. The body is off the car for paint plus to fix things like this easier, so firing the b!#%h up is not a viable option. Time to strip it down and reseal it.
Bill Stradtner