1998 CADILLAC STS - EXCESSIVE OIL CONSUMPTION

burneeburnee Member Posts: 2
edited April 2014 in Cadillac
MY '98 STS HAS BEEN GOING THROUGH A QUART OF OIL PER 1000 MILES OVER THE LAST 8 MONTHS. I JUST LEASED THE CAR LAST YEAR WITH 49,900 MILES ON IT AND I FIND THIS OIL CONSUMPTION TO BE EXTRAORDINARY. THE DEALER TELLS ME THIS IS NORMAL FOR THIS CAR BUT I FIND THAT HARD TO BELIEVE. I'D LIKE TO GET THIS RESOLVED SOON AS I'VE ONLY GOT 6000 MILES LEFT ON THE 'CERTIFIED' WARRANTY. HAS ANYONE EXPERIENCED SIMILAR PROBLEMS? IS THIS NORMAL? IF NOT, ANY RECOMMENDATIONS REGARDING REPAIR AND/OR RECOURSE?

Comments

  • adc100adc100 Member Posts: 1,521
    Turning of the caps lock and posting this under "Engine Oil-A Slippery Subject" This will be classified as "normal" according to the dealer. But not for me. You will be fighting an uphill battle.
  • gserep1gserep1 Member Posts: 92
    Hello,
    I have a 1998 Seville STS that was bought new in June 1998. The engine has ALWAYS used oil in this manner. It really detracts from an otherwise beautiful running car. There is so much controversy about this oil consumption.

    Whoever said that fighting this problem with a dealer or GM directly would be an UPHILL battle, REALLY knew what they were talking about. The car now has 28,000 miles, and although I love it, would NEVER buy another GM car with this engine. The family inherited it after my father passed away. It was his pride and joy, and he had it serviced regularly. Oil is still changed every 3000 miles at the dealer.

    I also have another comment. The book says that oil capacity is 7 quarts, but it is really 8. I also noticed that synthetic oil is not recommended for this engine, and I have always been curious.

    I have written Cadillac, and contacted Mobil 1. Mobil 1 says to follow the manufacturers recommendations, even though Mobil 1 should work beautifully in it. I enjoy driving it, but it is not an everyday car. Besides, the mileage is terrible if you use it in town...(12 to 15). It is great on the highway....nearly 28 at a steady 70-75 on premium fuel. I understand that the new Cadillacs ALL use regular gasoline...(due to improvements in the fuel delivery and ignition system.) My belief is that it could have been done years ago, but Cadillac just got with the program.

    I have also noticed the oil consumption problem on other multi-valve engines...(most notably the 32 valve 4.6l Ford Mustang COBRA engine, and the 4.6L Lincoln Mark VIII engine. Ford also says not to use synthetic oil, and they both use oil at an alarming rate. Could be something about the multi-valve design. Why would they recommend a regular oil over a synthetic? Doesn't figure in my book. This may be the tip of a much bigger problem. I would check into recalls at Cadillac to see if there is a service bulletin or recall.

    Oh well, I have theorized long enough. Good luck on the oil consumption problem.
    GSEREP1
  • adc100adc100 Member Posts: 1,521
    Found this information under "Alldata" service bulletin: # 85.76-60-04A AUG 98 Engine Oil Consumption Guideline .


    Here's the link: http://alldata.com/TSB/08/980819FR.html

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Synthetic---I have only heard of one instance of synthetic oil not being recommended for an engine, and that wasn't even a caution from the manufacturer, but rather a noted rebuilder--he insisted that the synthetic oil adversely affected the apex seals on Mazda Rotary engines.

    But why synthetic would not work well in a plain old Cadillac engine is beyond my guessing. Is that actually printed in the owner's manual or did a dealer mention this?
  • burneeburnee Member Posts: 2
    THE WIDE VARIANCE IN GAS MILEAGE GSEREP YOU EXPERIENCE IN YOUR CADILLAC STS (12-15 CITY, 28 HIGHWAY) IS INTERESTING. UP TO THIS POINT, MY AVERAGE MPG HASN'T DEVIATED MUCH FROM 17-20, CITY OR HIGHWAY.
  • gserep1gserep1 Member Posts: 92
    Hello,
    Yes, I was as suprised as you about that warning. I have been a synthetic user for many years, and it seems that some manufacturers of Multi valve engines do NOT want synthetic oil in their engines. The ones I mentioned are SPECIFIC. Ford's 32 valve engine in the Cobra and Cadillac on the Northstar are very specific. I have been very perplexed about this phenomenon for a while.

    I am usually a faster driver, but I use the electronic monitor on the Cadillac's dashboard display to drive by on long trips. I drive from the San Francisco area to San Diego quite often, and I set the display to show INSTANT fuel usage. When I start out on a long trip after lots of city driving, I see an average of between 12 to 15 mpg. But steady driving at speeds of 70 to 75 causes the average to go up as I drive. I change back and forth between INSTANT and AVERAGE MPG, and I am amazed at the difference that steady driving can make in this car. It can be boring, but I resist hot rodding unless I really have to. Of course, I don't drive it like that always. The power is much too intoxicating to resist all the time. I am not sure where you drive, but here in California, on the long INTERSTATE 5 route (very familiar to all of us long distance California drivers), it is possible to go for MANY, MANY miles without so much as touching the accelerator pedal.The road is relatively flat as well, and once momentum is built, it is smooth sailing..but BORING sometimes. I drove like that on one trip JUST TO SEE what it would do, and it really does get close to 28 MPG if driven steadily(not SLOWLY).

    When my sister drives it, she has a lead foot even in town..(loves the power too), but I always get better mileage than she does.

    Going back to the oil consumption and synthetic oil usage, read your owner's manual carefully, and you should see it. I was all set to put synthetic oil in this car, but decided not to..at least until the 4 year/50,000 mile warranty is over. At this rate, the 4 years will pass WAY before we get 50,000 miles on the car. I go to McNevin Cadillac in Berkeley California, (where my Dad purchased the car), and they strongly recommend not using synthetic oil....probably to ensure that THEY get repeat business. This car is really overserviced. My sister uses the 3000 mile rule instead of the oil maintenance indicator on the panel (0 to 100% oil life). I like to listen to the car, but she drives it much more than the rest of the family.

    Thanks again,
    GSEREP1
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