Twin_Cam wrote:
That's what happens when oil pan is two farking pieces! Cadillac techs joke that the Northstar replaced the B series (or whatever the designation for Cadillac's V8 was) because the B series couldn't pass an emissions test. The N* will pass an emissions test but will pollute anyway by continually oiling down road surfaces 
The thing is, the Northstars aren't really bad for oil leaks. They're just very laborious in order to repair an oil leak that is a nuisance at best. (Removing the trans, of course, requires first removing the subframe)
The 4.1/4.5/4.9 engine, on the other hand, was horrible. Horrible. Awful engine. Noisy, clattery, and leaked every fluid from every possible orifice. In FWD form the sheetmetal timing cover would leak oil and coolant, the sheetmetal water pump would leak, replacing THAT was a pain because the water inlet was a separate piece with its own gasket to an overhanging section of the sheetmetal timing cover but the water pump bolts held it all together.
The block was so skeletonized that the outside row of head bolts were exposed to the elements halfway down, so they'd rust.
Wet cylinder sleeves. Bar's Leak (or a GM partnumber for same) was actually called out as a coolant additive for every service, to seal up the lower O-rings where the aluminum would corrode away. Sometimes it even worked long enough for the engine to live longer than the rest of the car.
My favorite - the valve covers extended over the intake manifold like Ford FE or Chevy V6-60s. The oil drainback holes used the upper row of headbolts as oil return galleries to the valley. Maybe 3/16" drillings that went to wide spots around the head bolts. Being an all-aluminum engine, these would sludge up, at which point the heads would fill with oil and leak prodigiously out the valve cover gaskets. We spent two hours on an old 4.1 cleaning them out with various items. Later, we found a tech tip from someone who simply tapped zerk fittings into the oil drain drillings and pumped high-pressure grease in there to blow the sludge out.
The engine that I talk about that had an oil leak from an exhaust manifold bolt was a 4.1. We stuck a brake-like copper washer on the bolt and it stopped leaking. I still have no idea how that even works, nor do I really want to know...
The Northstar is not a bad engine in the least, and considering what preceded it, it's astonishing that it came from the same company, let alone happened in a single generation. Fixing the oil pan leak sucks, but at least it can be fixed, instead of just worked on. Fixing implies that the problem is solved.
