why is my car overheating and the oil is fix in coolant resouir? on 1998 Cadillac Catera

and oil in sparkplugs

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3 answers 3 comments
Sounds like blown headgasket. Check compression, pressure test cooling system , also a chemical test kit you can get to check for combustion gas getting through cooling system.
oil + coolant = blown head gasket...
Smoke or steam from exhaust? Engine oil milky in color?
Pogo stick or skateboard?
Radio Flyer.
Red Ryder?