I have a leak that looks like its coming from the rear of the oil pan. My uncle in law, the builder of the car, said he tried to fix the leak but with no luck. I can only assume he tried to re-seal it. Is it possible for oil pans to warp? Is there anything I should look for when taking it off besides obvious gauges in the mating surfaces? What do you use for sealer? Thanks, Sean
Has there been any recent work done on the engine? Check to make sure that the crankcase is properly vented. If it isn't, it might try to push oil out of places where it normally shouldn't ought'a.
To get to that I have to take off the trans, flywheel and clutch right? Can I leave the motor in? Ironically I drove it a few minutes ago and now it is leaking the worst I have seen it. Maybe because I had the front of the car jacked up?
I have owned the car the last 750 miles. No motor work that I have done, just oil change to Brad Penn 10w30 semi synthetic. I don't know what oil was in the motor before. The block was bored to 409 ci and fresh pistions. He said I would have to think about getting new rockers in the future.
I don't know what kind of a bellhousing setup these engines used with a manual trans. But there may be an inspection cover down below that you can remove. You may have to use an inspection mirror and a flashlight but you might be able to peek up between the flywheel and the engine and see if the back of the block is covered in oil. Also look at the back of the block on the topside of the engine to see if there might be an oil galley plug or oil pressure switch that might be leaking.
Took some pictures. It drips from four places I can see, the bottom of the bellhouse closest to the motor, the bottom of the starter, where the starter bolts to the block, and off the rear oil pan bolts. The top rear portion of the block is oily, near where the distributor goes into the block. There is a flat cover that sits on top of the block and below the intake manifold, the rear section of that appears oily also, you can just make out the blue gasket in one of the pictures.
Check at the back side of the distributor & engine block. There's supposed to be an O-ring on the distributor upper shaft and if the O-ring wasn't installed, oil will work itself out & down the backside of the block.
I use 10w30, I said 5w30 in previous post by mistake (snowblower uses 5w30). This oil is formulated for older engines, or so they say. I did research on the best oil to use for the motor and this is what I picked. http://www.penngrade1.com/Default.aspx
I found another inspection cover, for the fly wheel. There is oil dripping off the inner edge of the fly wheel, closest to the block. That must be the main seal leaking? The oil dripping off the starter is coming from a fabric wire loom that runs down the rear of the block. The wire goes from the alternator to the starter. There must be some place on the rear exterior potion of the block that is weeping oil. Hard to see where, the motor is close to firewall. Then there is the oil coming off the bolts that secure the rear portion of the oil pan. Must be a leak at the oil pan? or is there a way the oil from the main seal makes over there? I wouldn't think it possible given all the lips and edges, but I have been wrong about similar things before. To fix it right how involved of a repair do you think this is? I have experience with modern snowmobiles, atv's and dirt-bikes (rebuilt several 2 stroke motors from the crank up). Zero experience with an older automobile motor like this.
Rear main seal and/or the wedge square seals or silicone sealer on the outer sides of the main bearing caps missing? http://nailheadbuick.com/how-to-install-a-rope-seal-correctly
It could be the rear main seal. It could be the rear seal of the oil pan. And/or it could be oil from somewhere higher up on the back of the engine. Oil running down from the top of the engine is a little trickier to track down. Once it gets to the flywheel it gets flung everywhere. As does oil leaing from the rear main seal. And it can flow off in directions that defy gravity, so assume nothing. You could pull the engine and/or trans and throw money at some seal and gaskets and it might fix it. Or not. It may be worth doing a little more diagnosis of where the oil is actually coming from. Get some degreaser and try to clean up the back of the engine as best you can, both inside the bellhousing and around the outer part of the block. Then run the engine a bit an look for fresh traces or where the source of the leak is. You still may have to pull the trans and/or engine to fix it. Or you may get lucky. Did we ever find out if the crankcase is properly vented? Also pull the valve covers and make sure the oil drain-back holes aren't plugged up, trapping oil on the top of the heads.
More than likely the rear main seal. Rope seals are fine as are rubber seals. I've done them with the engines in the car before but it's a PITA sometimes.
took the valve covers off and the oil is draining back. How is the block normally vented? I do not see anything.
Like tejays said, older motors are alot more porous, and the synthetic oil will seek the voids alot easier than conventional oil. That would explain the leak getting worse.
I'd spray it down with brake cleaner or degreaser, or biodegradable degreaser and start the engine and let it get good and warm and see where the leak originates from. If you see oil above the pan gasket, it could be the main seal, or as mentioned above there are two wedge seals between the main cap and the block. If it's above that its most likely the distributor, oil pressure fitting, valley pan etc. I doubt it would be the oil galley plugs as you would most likely see be losing a whole lot of oil, and oil pressure would be really low. Check a Buick motor manual, or www.nailheadbuick.com for information and tips on Buick rear main seals. A friend just went through this on a new nailhead build. The rear main was rubber (not rope) and it was just a little too tall and squashed between the cap and the block creating a leak. At the same time he added a little gasket adhesive to the two wedge seals and the problem was solved
At the minimum the c/case should be ventilated to atmospheric pressure. This can be done with breathers in the valve covers or a vented oil fill cap. This relieves pressure in the c/case as a result of blow-by and engine heat. Ideally the engine might have a breather in one valve cover and a vacuum hose and PCV valve in the opposite valve cover. This pulls air thru the the engine and clears out moisture and contaminents and actually puts the c/case under a slight vacuum. http://en.wikipedia.org/wiki/Crankcase_ventilation_system If enough pressure builds in the c/case it may try to push gaskets and seals out of place in an attempt to relieve the pressure.
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