Low Oil Pressure + Freeze Plug in oil pan 1995 Cadillac 4.9L V8?

  • Thread starter Thread starter Kendel S
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Kendel S

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Hello,

I have a 1995 Cadillac Deville with the 4.9L V8 and the top end of the motor is not getting oil pressure and I pulled the oil pan to find what looks like to be a freeze plug about the size of a dime.

I have a low oil pressure light and the valve train is noisey. I went to cadillac and no one there can tell me where on the motor this plug comes from.

The plug was damaged on its way to the oil pan, it is bent in half and scratched and scored. Please help me so I know where to start looking,

thanks
kendel
 
Seeing there's no coolant in the oil pan what your looking at is one of the oil galley plugs. Most likely you'll find it came from the front of the engine block and got mangled up by the timing chain or gears. So the first place I'd look is behind the timing cover. Usually oil galley plugs are threaded, and people wonder why G.M. is on the skids.

Check out the link for a picture looks like a freeze plug only smaller diameter is 45/64" or .700 slightly smaller than a dime, Dorman part # 555082
 
It is a common problem in many old Cadillac engines for the head to not receive proper oil pressure. The oil pumps in these cars are like tinker toys. If synthetic oil has not been used in this engine regularly, many parts of the lubrication system can fail. They usually fail, anyway from the design. The part you see in the pan most likely is the oil pressure relief valve, or a part of it. It is supposed to regulate the oil pressure throughout the engine. I have had 3 Caddy's literally break down on the way to my shop with this problem. Your best solution is to replace the oil pump, complete with new pressure relief valve. Hopefully, an aftermarket part will last longer than the factory unit. It is also possible that the cam bearings have spun around in their shells, and lock off oil pressure feed to cam bearings and head. In Detroit, there used to be 10 shops that only rebuilt Caddy engines. They were constantly busy!!!! Good Luck!!!!
 
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