454 Leaking lots of oil ?'s

[low&slow]

Got a 454 in my '69 c10. Put the truck on my cement working pad last night. Went out there this morning to notice a puddle of oil under the truck and a flat tire. Looked under there and it seems to be leaking from the rear main seal. That's where the oil is coming from so that's what I'm assuming.
How do I go about fixing that without pulling the motor?
I know I have to drain the oil and pull the pan, but what else do I have to do fix it?
Step by step instructions would help greatly. Thanks guys and Merry Christmas.

[Shyguy]

I have never done it, but my son says you have to pull the motor. Hopefully some one else will chime in that has done it in the truck.

Also check and make sure the oil pressure line just above the oil filter is not leaking.

[low&slow]

I sure hope I don't have to pull the engine out. But I sure do hope someone else can chime in.

Thanks for your input.

[vectorit]

If it were me.

I would make sure that the leak was coming from the rear main seal before anything.

I have seen distributors missing a gasket, and oil then leaks down the back of the engine. Also the rear of the intake manifold, or a valve cover gasket can cause oil to run down the back of the engine.
Could also be a leaking oil pressure gauge line.

As for doing a rear main seal? Personally if I had to do it, I would pull the motor and re seal the whole thing to do the job right.

[cdowns]

also chech the oil filter

do you have a PCV system imstalled if not a build up of pressure could cause the valve covers or oil pan gassket to blow out and leak oil

[into69z]

Well, I had the same problem so here goes! I was leaking so much oil that I thought the EPA was coming for me. I had just built the engine(1974 454) and everything was brand new-even bought the high dollar one piece rubber Fel-pro pan gasket. Had about 2 qts loss after only 300 to 400 miles. I thought I installed the the rear main backwards or I somehow screwed up the pan gasket. Went to my buddies shop that had a lift and we both tried to figure out why I was losing so much oil.( we never started the motor before we started checking for leaks so that would be something to do before you start-clean everything on the motor and run it while you look under it for leaks-BE SAFE) The only way to check the rear main was to get the pan off so I pulled the motor mount bolts and jacked the engine up as high as I could but there still wasn't enough clearence( thought it would be better when I built the motor to put a 7 quart pan on instead of the 5 qt, so the pan was bigger). The pan would not clear the front crossmember, so I pulled the trans mount and the center carrier bearing support so I could move the whole drive train back about 3 or 4 inches and almost got the pan off-but it still needed just a little more(note: my 69 came with a 350 originally so it has a low hump -if you have a high hump you might get more clearance by taking that tunnel off). Anyways, I finally had to reach inside the pan and take off the oil pump and pick up and then I could get the pan off-what a B^%ch! When I could see the rear main seal, I found that I had installed the seal correctly and the pan gasket did not show any obvious signs or problems so I cleaned everything up and put on a normal pan gasket that I have used in the past along with new bolts because I had used some chrome bowtie chinese bolts that seemed to let the oil weep by the threads. I put everything back in it's place and bolted down the engine, filled it up with oil and started it to check for leaks. Everything looked great but I had a leak on the front of the motor and it dripped a lot while I was warming the engine up. It was coming from behind the power steering bracket-there is a pipe plug fitting there that plugs off the main oil galley for the motor! The plugs was so loose that had it not been for the bracket, it would have fallen out and really moved some oil! I was able to get an allen wrench and once the plug was tight, my oil leak problem is gone-not a drop anymore. Sorry for the long post but unless you have a lift and the right tools( we used a trans jack and some frame stands to hold everything up while unbolted), your best bet is to pull the engine. It took me two days to get my truck done but had I just pulled the motor, I think I could have been done in one day. I did not take pictures but you should be able to figure it out.

[low&slow]

Awesome. Thanks for all the replies guys.

Vectorit and Cdowns - I will defiantly check all the out before I dive into anything. I'd hate to spend all my money on trying to find the problem and not have any money for gas to test what I fixed. Thankfully I have another one I can drive in the mean time while I'm fixing this one. Since I have the other truck, I'm just going to pull this motor to see exactly where the wet spot starts, then go from there.

Into69z - Thanks for all the information. I'm just going to pull the engine out. Like you said it was a B^%ch to get that pan off. My truck as well came with a 350 in it so I don't have the high hump. Beings I don't have a shop to work in and our high is in the 30's for weather, it would be faster and easier to pull it instead. Tomorrow during the day I will defiantly check out that plug and see if it's coming from there. I don't think it is because the front half of the oil pan is dry. It's dripping onto the flywheel from the crank area, but like the others said, it could be coming from higher up. The 454 I have is out of a 1973 and is bone stock other than the carburetor and fan, so it doesn't really surprise me that it's just now starting to leak from anywhere.

But I will defiantly let you guys know what I find out about where the leak is coming from. If I have anymore questions or concerns about anything, I'll just keep this thread and ask on here instead of making a new one each time.

Really appreciate the help guys. Thanks again.

[WAAF]

box stock 73 454 with I'll guess a rope rear seal.. by chance are use use'n syn oil..
syn oil or syn blend oil will leak right past 40 y/o seals, hell sometimes they leak in new builds that use the "date correct type gaskets)
just something to think about, before you go pulling it..

[1968SWBBigBlock]

I like your idea of pulling it.
I have changed my a couple of times with the motor still in the truck.
With my old Milodon pan I did not have to jack up the motor - my Moroso pan is a different story.
I take out the transmission bolts on the crossmemeber and the tranny mount - pull the bolts on the engine mounts and jack up the motor as high as I can.
Once you drop the pan you may have to rotate the crank to get the front counter weight up into the block - this will let the pan pull out.
I like the one piece oil pan gaskets - Mr Gasket brand is a favorote over the fel pro but I would use both.
The rear main seal is pretty stright forward - pull the rear main cap - this half of the seal you can pull out by hand - the seal in the block can be a bear - espcially if it is old.
Use care since you do not want to scratch the crank or seal area
It may help to use the lower old seal to push out the old uppper seal
I always put a small amount of assembly lube onto the seal lip so it is not dry at start up.
When I install the seals I also set them up so instead of the seal split being at 9 and 3 oclock I shoot for 8 and 2 olclock - that makes the split lines fall inside the block and inside your rear main cap. Helps keep them from leaking.
torque down your rear main cap and clean everything and reassemble.