rizZO-6

I drained my oil 3 weeks ago so that I could replace the oil pan gasket and rear main seal. The pan is still off and most of the oil has stopped dripping from the motor but I'm still getting several drops a day in the same place on the garage floor. I noticed the oil is coming from behind the cover on the bell housing. I didn't completely remove the cover on the bell housing but I was able to remove the screws and pull it away enough to wipe the back of the cover and the lip of the bell housing. But somehow I keep getting oil there. Where could this be coming from that its running down the back side of the cover and how is there still so much dripping from that one spot when there's no oil in the motor?

JoeMinnesota

What do you mean by cover on the bell housing? You mean the dust shield at the bottom front of the housing? If the back of the block is covered in oil, or oil on the flywheel and in the bell housing, there may be a puddle in the bottom of the bell housing. A few drops a day isn't much. The top half of the rear main is above the shield and inside the housing, so could have leaked there a long time. I would also check your oil pressure fitting if it located at the rear top of the block, behind intake and near the distributor. If that happens to be leaking it will run down the back of the block.

If your rear main or that fitting or rear of the intake were leaking for quite some time, there is probably an oil residue down the back of the block and in the bell housing. I would remove the dust shield (may have to pull the starter) and flush as much as possible with brake cleaner.

DUB

Please do not take this the wrong way.

I clean it very well...then I add UV dye in the oil so I can see the leak with my UV light to find exactly where it is coming from after I have allowed the engine to run for a while.

Hoping that you used the 'shoehorn' piece of plastic when you installed the rear main seal is important as you knwo so you do not damage it. Applying the sealant where needed also.

The comes the oil pan and the gaskets and the sealer needed to do this also.

By having the UV dye in your oil...which I hope is relatively clean...it will allow you to be able to see if the oil is coming from the plugs at the back of the engine or the freeze plug cap for the camshaft.

Not to long ago I fought with a 427 to get it to stop leaking and I am glad I had the UV dye in it...because when I dropped the rear bearing cap....I could tell right away that I had a problem in the rear main seal and nothing above it was the problem....due to being able to see the glow in the dark oil when I hit it with my UV light.

http://tracerline.com/all-products/lamps/

Or find something that works for you. And I get the UV dye from NAPA. And having the yellow lensed glasses also helps.

DUB

NeverTooOld

The oil you are seeing most likely came from one or both of the valve cover's lower corners. Try snugging up the valve cover's bolts and see if that stops it. The only valve covers that don't leak are the cast aluminum or magnesium covers and when using neoprene gaskets.

rizZO-6

@ JoeMinnesota - yes by cover I mean dust shield. I will take a look at the areas you mentioned to see if oil is coming from there. I didn't notice any oil on the fly wheel though.

@ DUB - yes I used the shoehorn when putting in the rear main seal and used RTV in the correct places. I have not put any oil back into the motor yet. I did the seal on Fri and had wiped oil off the dust shield and off the garage floor. I went back out Sat to put the oil pan and gasket on and noticed more oil at the bottom of the dust shield and on the floor. I will probably look into getting the dye like you did. Thanks for the tip.

@ NeverTooOld - I have the original orange painted metal covers. I did torque them to 45 inch lbs but I have not had them off to replace the gaskets. Maybe that's next on my list since I was thinking about changing to the finned aluminum covers anyway.

NeverTooOld

Yeah, the stiff cast aluminum valve covers are the only way to go. When used with premium neoprene gaskets they are almost leak proof. And quite frankly they look a lot better too! The trick is to use oil resistant RTV to glue the gasket to the valve cover and let it cure overnight before installing them. The majority of the oil leaks are caused by oil getting on the top of the gaskets and then that oil seeps between the gasket and the valve cover so that's why it's imperative to glue the gasket to the valve cover with leak proof RTV. I have always used Permatex Ultra Black but I'm sure other brands will work just as well.

Duane4238

I got my UV led flashlight on Ebay for under $10.00. Definitely a good investment.
Duane

derekderek

Most likely your previous rear main seal leak got oil all over the back of the flywheel. Fill it with oil. Take dust cover off bell housing. Wipe off flywheel. Run it. The spinning will sling the rest off, so it'll drip for a little bit yet.

68notray

There are other potential sources on the back of the block. There are a couple of oil galley threaded plugs AND of course the giant cam plug. I always take great care when installing all of those to make darn sure they don't leak

NewbVetteGuy

This is an amazing troubleshooting technique; I had no idea this existed!

Can you finish running the oil for the rest of it's typical life after adding the UV dye or do you need to change the oil fairly soon?



Adam

DUB

So if I read this correctly...you have not even run the engine after you did the rear main seal...and had NOT yet installed the pil pan...an you went out and saw oil drips....correct???

That does not surprise me that you had oil still dripping after doing the rear main seal and NOT the oil pan.

I would put oil in it and run it and see what you have...and if you want to add some UV dye ( like previously suggested) makes finding the leak easier.

I run the oil after I add the UV dye The amount of dye you use...especially IF your oil is not black like coffee.....is really nothing at all and does not effect the oil...or at least I am not having cars come back in with the connecting rods hanging out of the oil pan.

This same dye is what I use in power steering system leaks also.

And for what it is worth..and might not mean much at all...but on the countless engines I have re-gasketed. Valve cover gaskets generally do not cause for an oil leak to drip at the very bottom of the pan. These leaks usually stop and drip at the end of the block above the oil filter or wick down onto the starter and drip off the starter bolts. The oil is not wanting to travel horizontally across the edge of the oil pan flange and then drip from the bottom of the curve in the pan where the gasket is.

YES..the oil might get blown onto the inspection cover and drip at the bottom of it...but it is not going to get on the backside of this inspection cover all the way up to where it meets with the curve in the oil pan by the rear main.

DUB

rizZO-6

That's correct no oil was in the motor or had been for 3 weeks. Oil pan was still off. Car was on jack stands on my level garage floor. It just seemed odd that oil had dripped more than several times in this one location when the bottom of the motor had stopped dripping. I have since buttoned everything back up, added oil, and wiped off the oil runs. I started the car today and backed it out of the garage. Wanted to take it for a drive but the wife already had plans for me. I haven't seen any more oil runs on the bell housing or dust cover so far. I did notice on top of the block by the firewall there is a lot of grime where oil may have been leaking there at one time (or maybe still is). When I have more time I will check it out. Thanks for the responses and input.