1990 buick lesabreApril 19, 2010over heated now have gas in oil. Keywords:Overheating 1 thought on “1990 buick lesabre” Jaxer April 19, 2010 at 8:05 pm No worries about the gas in the oil. May have a sticking fuel injector. Change the oil and filter and run the engine to operating temperature. if the oil level increases, remove all the spark plugs and cycle the key to ON and OFF to activate the fuel pump while checking to see which cylinder fills with fuel. Then replace that injector. Comments are closed.