Cadillac Repair: 86 Cadillac Sedan De Ville 4.1, oil drain plug, intake manifold gasket

Question
I have an instantaneous water leak into the oil sump. If you remove the engine oil drain plug and remove the oil, then pore water into the radiator it goes straight into the sump and out the drain plug.  A mechanic renewed the inlet manifold gasket, which didn't fix it, then we replaced both head gaskets and another inlet manifold gasket. It still pours water into the sump. Can you help or point me in the direction of another expert? Thanks in anticipation. Andrew

Answer
Hi Andrew, Cadillac has had problems with this engine when it first came out and they later had a recall campaign in '85 or '86 to address coolant leaks. Repair procedures are differant from most other engines and just anyone shouldn't be allowed to work on these or they can cause damage without knowing it. What Caddy did was use seal tablets in the radiator to help with seapage in gaskets. Unfortunately your problem is past that since the water comes out the oil drain plug almost as fast as it goes into the rad. Usually where they leak is on a corner of the intake manifold gasket but having replaced it twice you would think that the leak is somewhere else or the tech. would have seen something damaged while it was apart. That somewhere else might be the bottom of a cylinder liner because there is a small diameter o-ring that the cylinder sits on and seals to the cooling system. Unless you overheat your engine or rotate the engine with the cylinder head off there shouldn't be a problem with the seal. What I would do is remove all the sparkplugs and see if water/antifreeze is getting into a specific cylinder. If all pistons are dry then remove the oil pan and see where the leak seems to be comming from. Then you will know what to take apart and fix. If it is the o-ring then there is a special procedure useing a cylinder height gage that only a Cadillac dealer would have and know how to use. It might be best to put a differant engine in your car because it doesn't take alot of time before the oil/antifreeze mix makes a camshaft lobe go round from a egg shape and bearings wear. Sorry to be the bearer of bad news. Bill