The drain plug is leaking on my 78 I just put a copper washer on the plug too. What should I dok, go plastic? it is dripping I "think" the rear oil pan stopped leaking. Man When one leak is fixed 5 more start. The motor will NOT SEAL and it is driving me insane.
Dustin
I just want to get it to the point that I can run Mobil 1 and not have a fat puddle under the truck. I want the best for it but it has treated me like crap.

 

Try switching back to a regular oil instead of synthetic. In older vehicles synthetic oild tends to leak bad, difference in chemical makeup. you can find information on the internet about this.

 

I doubt the source of your leaks is the synthetic oil. I have changed many high mileage vehicles to synthetic will no problems. Your problem sounds like a well worn engine showing its age by marking its territory. It is very common in older engines to develop a new leak everytime one is fixed. The leaks are caused by blow by pressurizing the crankcase. The leak forms at the path of least resistance. When that leak is fixed a new path is found and so on.

 

It has Delo 400 15w-40 right now. It has new rings and gaskets 3-3.5 years ago. The engine has 135psi +- 5 on all 6 no oil in the air cleaner, no oil on plugs, 53 PSI cold 30 ish hot oil pressure I woud not say it is a " worn" engine by any any means. I'm begaining to think FELPRO are crap

 

Even a brand new engine has blow by, just less of it. Many oil leaks are caused by something as simple as a malfunctining PCV valve. If it gets plugged crankcase pressure will build and a leak will happen at the weakest seal.

 

Silver Streak,
I have not thought about the PCV valve till you mentioned it. I changed it when we rebuild the engine, it has about 5k miles on rebuild but it has been 3-3.5 years so It does sit alot. I pulled it out about 2 months ago and it "rattled" when shoock. Does it still need replacing( the source of my leaks)????
I mean If the rear seal has been replaced with only 5K and it is leaking(seaping now, but may stop) Now the drain plug. I would not think a new rear seal would leak with only 3.5yrs and 5K on the motor... I'm begainning to think PCV valve right?????

 

Are we talking a one piece seal. You had to pull the drive plate flywheel to replace it,correct. You did put a sealer on the bolts holding the flywheel/drive plate, I hope.
those holes are bored right thru and oil will pass the threads.

 

Ya, It is one piece.
I don't remember about the sealant on the threads I don't think any was put on. It was never mentioned to me that there should be. Thier was nothing on the threads when I took it apart. I have a big concern about my dang leaks. The rear seal just started to leak and so has the drain plug within about a month of eachother. What I'm trying to say is that the rear seal has been BONE dry for the last 2.5-3 years. I think I wil put a plastic washer on the drain plug.

 

This sounds like a silly question but are you useing crush washers under your drain plug? This are a one time use washer that gets crushed when tightend and makes a seal. NAPA here in the sticks of Oregon has them in stock.

 

i just went thru alot of the oil leaking everywhere..like was already said,once one starts..seems they all start..i just replaced my head on my 84 with a 77 rebuilt head because mine overheated one day & not noticing untill i looked down & seen the temp gauge pegged..cracked the head..replaced the head & found the oil pan was leaking bad..replaced that & while in there put a new high volume oil pump in it since the oil pressure always seemed a little on the low side once warmed up..still having a bad leak which i THOUGHT was the oil pan gasket because it was leaking at the rear of the oil pan by the tranny..all done & still leaking BAD(lost 5 quarts in one day)...i got to looking at it closer..coming from the engine/tranny plate in between the 2..so its the rear seal..pulling the tranny saturday to replace it...i also had the same problem with my drain plug leaking.my son apparently stripped it out one time when he wanted to change the oil..i bought an oversised plug for it but still dripped a little..so while i had the oil pan off i just used the oversised plug which was a big nut with a smaller pipe thread type bolt inside it for the drain(bought it at pep boys)..i just welded it to the pan & cured that problem
seems like alot of work for an old engine but this thing has & STILL pulls my loaded car trailer with no problems whatsoever

 

It runs good with nice compression and oil pressure. Just marks her territory

 

buddy if your drain plug is still leaking there are oversize drain plugs you can buy that will fix worn or stripped threads in your oil pan. You can get them in places like schucks and autozone etc.

 

the drain plug is dry now, it is just the back of the oil pan/rear main area it leaves a 4" puddle, it does not leak when the motor is running only when it is off, sitting overnight.