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Dan, Technician
Category: Cadillac
Satisfied Customers: 24445
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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Cadillac sedfan deville: i have a 1998 cadillac deville with

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i have a 1998 cadillac deville with 94,000 miles on it i bought it ten years ago with 36,000 miles on it. garage kept and well taken care of. it always used a quart or two of oil between changes which i do usually around 3,000 miles but lately if i make a trip of 400 miles i;m a half a quart low on oil. and i can at times smell oil inside the car. not a drop of oil on my garage floor. never seen a spot of oil on my trunk lid and have yet to see any smoke from the exhaust. i recently changed the oil pressure switch aftr being told they do leak at times but it didn't help. any suggestions?
Welcome to JustAnswer, my name is XXXXX XXXXX I'm here to help get your problem solved. These engines had some problems with the piston rings building up carbon on them which would cause it to burn oil. I would start by replacing the PCV valve then get two cans of seafoam which is a engine clean you can buy at your local parts store. One can of seafoam will go into the oil then you can use about 1/3 of the other can by sucking it into engine with vacuum line, you can use the vacuum line that goes to PCV valve. Pour the seafoam into a cup then use the vacuum line to suck it out of cup while the is running. Shut it off and let it sit over night, then in the morning run in low gear at high rpm to burn out any carbon deposits on the rings. The catalytic converter and exhaust resonators do a good job cleaning up smoke which is why you never see anything. Let me know if you have questions or if there is anything else I can do to help. Thanks
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