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97 Deville oil consumption and antifreeze leak

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I have 137,000 miles on my Deville but I have put in about 5 quarts of oil since last oil change but see no leaks on the driveway. I can smell oil but hard to see where it could be coming from and the antifreeze leak is slow but when i took it to my local GM dealer they said they put it on a pressure test and could not find a leak. I am frustrated because I drive alot of miles and I am actually afraid to go out of town with the car with these issues going on. Any ideas as to what to check for and estimated cost would be appreciated as money is really tight for me.

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The first thing I would suggest is that you run the OBD codes, write them down, and post them here. See the link in my signature block for instructions.

The next thing I would suggest is that you have your coolant tested for combustion products. This will rule out head leakage as the cause of your coolant loss, and prevent lots of anguished comments later in this thread.

Coolant loss in a system that passes a pressure test are usually due to a bad radiator cap or coolant that is less than 50-50 antifreeze. There are other things, too, like slipping water pump belt and such, which we can check after we are sure that the system holds pressure and that it is 50-50 antifreeze or better.

-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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In the summer and early fall you can run the heavy duty diesel oil 15-40w rotella. It cuts consumption to more than half as I verified from one of my customers.

Also, if you think you have a head gasket issue run the overflow tube from the surge tank into a plastic water bottle in the engine compartment.

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