Engine oil leak question

[JoeyB]

Ok, I about broke down today. I have my conversion almost complete and if it wasn’t for all the snow today I was going to try and start this thing. So yesterday I put oil in the engine and primed it. Took the valve covers off to make sure oil was moving through the entire engine. Put the valve covers back on and closed shop for the night.

Today when I check under the truck I found oil. Not a lot but still it was oil. It looks like it was coming from the area the oil pan mates up with the seal around the crank shaft. It's been pretty cold here and last night was the first time I put oil in and primed the engine. A guy told me due to the cold and the engine has never been started, the seals may need to expand when you start the motor and I might not have a problem. Was this guy making me feel good and has anyone seen this before? I'm having nightmares about having to pull the motor and reseal a few things.

 

[Iron Ranger]

Not sure. Could be a few things. The cold/no start is a very good possibility.

Is it a 2-piece rear main seal or 1 piece?

How much is "not a lot"? as in 2 or 3 drops?

Take a flash light and look over the rear of the motor and monitor the leak. If it's still leaking, I can only think of the rear drain plug since oil hasn't been sloshed around the engine yet. If it isn't, then it could be the cold new seal.

Might even be some runoff from when you took the valve cover off.

Engine running/heat should fix it if it's cold.

 

[JoeyB]

Thanks for the e-mail Iron Ranger. It's a two piece main seal. The engine is a 1991 302 HO out of a thunderbird. I don’t believe it’s the drain plug because I could see the drop forming on the lip of the oil pan where it mates with the crank. I wiped down the oil on the pan and on the floor so I could watch it today while I worked on a few other things. Throughout the day it leaked a few drops (2 maybe 3) and it looks like it is now coming from somewhere else higher up on the block (that could be from when I had the valve covers off) but not from the oil pan where it was last night. The amount of oil it leaked overnight (about 16 hours) was a little puddle. Very weird and a little frustrating.

 

[baddad457]

Thanks for the e-mail Iron Ranger. It's a two piece main seal. The engine is a 1991 302 HO out of a thunderbird. I don’t believe it’s the drain plug because I could see the drop forming on the lip of the oil pan where it mates with the crank. I wiped down the oil on the pan and on the floor so I could watch it today while I worked on a few other things. Throughout the day it leaked a few drops (2 maybe 3) and it looks like it is now coming from somewhere else higher up on the block (that could be from when I had the valve covers off) but not from the oil pan where it was last night. The amount of oil it leaked overnight (about 16 hours) was a little puddle. Very weird and a little frustrating.

If it's a 91 motor, it's got a 1 pc rear main seal. I've fought the same battle with my 302's as well, it comes from the rear of the valve cover gasket. The oil pools deeper than the gasket surface while the engine is running and works it's way out while the engine is running near as I can tell.

 

[JoeyB]

Thanks for the response baddad457. Question...I haven't started the engine. How could the valve cover gasket be leaking? I have only primed the engine and I don't think that much oil ended up in the valves. Do you have any ideas how to get rid of the leak?

 

[baddad457]

I looked at mine today and I've concluded mine's due to the absense of baffles in my valve covers. It works up and out the breather on the driver's side and travels down the fins of the cover and down the rear. Check your gaskets and make sure the bolts are compressing the cover rail and gaskets.

 

[JoeyB]

Funny you mention that because I actually did that yesterday. I still had a few drops today. I tried starting it today but I have a few wiring issues. I'm going to try it tomorrow. I guess I'll see what happens.

 

[Twisted_Steel]

Just to make sure you don't have a bigger problem, swab the back of the engine with a piece of a rag on a wire and see if you have oil there. Mine had a rear oil plug loose up near the cam at the back of the block and it covered my clutch in oil. Go thru the access at the bottom front of the bellhousing, hopefully this is not where it's coming from. The only fix is dropping the tranny or removing the engine. Best of luck!