My 2001 Cadillac DeVille has roughly 89,000 miles. I inherited the car from my father about 18 months ago and have put only 1,000 miles on it. During that time, I've had to add less than 2 quarts of regular oil.
Given the car's age, I asked a local Cadillac dealer if I should switch to synthetic (also, synthetic is easier to find in stores so I can carry extra around). The service department said I should stay with regular oil, since that's what my father used previously.
I'd like to hear opinions as to whether or not this is sound advice. Thanks!
Adam
I believe the dealership is absolutely on target about oil choice. Synthetic (or for that matter, any magic oil additive) will NOT stop the oil consumption. and may exascerbate the problem. Years ago, an "acceptable floor" on oil consumption was 500 miles per quart. I'm assuming that you've checked for leaks, and that your dad kept the car in good repair, and didn't abuse it. Oil is relatively cheap compared to finding and fixing a problem on a 20 year old car. I own a 2006 SRX, and it burns a quart every 1000 miles--from the time I bought it when it had 11,000 miles on it... aside from the inconvenience of having to add oil, the SRX needed new catalylic converters at 100000 miles--- and that, I believe, had to do with the above average oil consumption. My suggestion is to use the oil the engine was designed to use. See if you can determine what driving conditions, if any, affect oil consumption--- hot weather as opposed to cold. Highway driving as opposed to intown. Also, did your dad indicate that the engine always used oil or that, over time, the consumption problem developed? Sometimes, as radiators age and invariably clog up, the engine;s internal temperature rise, and overheated engines burn oil. Hope this helps, James
If you want to use synthetic just because its easier to find I don't see a problem with that. I would not expect anything to change good or bad.
I believe what you're seeing is an artifact of the northstar series of engines. I bought a '97 for a work car in '99 and once it got beau coup miles, it started consuming oil. About a qt or two between oil changes(4K). I just increased the oil change frequency to down a qt, so I wouldn't have to bother.
The tolerance on the rings is set to decrease friction(I seem to recall 4 thou gap) and the pistons were coated. As they wear, there's quite a bit of "blow by" but it doesn't smoke because of the catalytic.
So I'd be looking at the price of the oil more than the quality as you're just burning up your money for oil. It won't get any better.
They were hard to work on, but I had good service out of that car. Great on the highway.
I had a 2004 Deville that I drove to 142K. Always used conventional oil (10w30), changed it often. It never burned any oil. Sold the car due to rust starting and possible head gasket leak starting. I still miss that car.
I had a 2006 Lucerne with the Northstar. It didn't burn much oil if any. They are built with low tension piston rings and there are some people suggesting to drive the car hard on occasion. Our 18 yr old son drove this pretty regularly and I dogged it a bit too. Leaks became a real problem at higher mileage and we sold it because of that. It leaked at the lower half of the block, dripped on the exhaust which triggered wife's asthma.. Only solution was remove engine to reseal.
Don't know what you all are finding now, but I have been a stringent user of 10W30 conventional oil in my old cars and I am finding it very difficult to find that in my local auto stores. Even tried Walmart who used to carry it and now nothing but synthetic or synthetic blends and very little 10W30 anything. Lots of 5W30 or 5W20. Began to notice this about 6-8 months ago.
Thank you all for your replies. I know the engine itself is prone to burning oil. My father mentioned this before he died, so I wasn't surprised.
I think I was wondering if using conventional oil vs. synthetic would be better or worse for the car given its mileage and age. Looks like it won't matter.
I have seen some "high mileage" oil —Shell is at least one brand — so maybe I'll try that.
Several messages mentioned 10W30. I have used 5W30 because that's what my father used. Am I using the wrong oil? I'm located outside of DC.
I had a 93 & 95 STS, 97 Concours, 2000 & 2002 DTS as new cars and all of them used oil at a rate of 1,200 to 1,400 miles per qt.
I never ran them hard
::)
Blends are a reasonable choice and usually cheaper than full synthetics if cost is a concern. Ford is/was big on them and walmart at least used to carry the Motorcraft branded oils.
I thought all the Northstars were Mobil 1 5w30 down to the mobil 1 logo on the filler cap? Seems like I remember that in the ads where they ran them without coolant.
The cap under the hood says 5W30.
Personally I have little respect for an engine that burns a quart
every 1K miles. I do recall our 56 Olds did use about twice that.
The 01 Honda used essentially no oil up till change time at 7.5K
miles. Now that it has nearly half a million miles, I expect to add
1 quart between changes. My 77 Olds 403 can go essentially
between changes at 2.5K without any extra oil. Bruce Roe
Understood. But this was my father's car. He absolutely loved it. He'll be gone two years in July. I cannot get rid of this car. And I honestly don't want to. It's the first luxury car I've ever owned.
Quote from: bcroe on June 04, 2021, 06:00:52 PM
Personally I have little respect for an engine that burns a quart
every 1K miles. I do recall our 56 Olds did use about twice that.
The 01 Honda used essentially no oil up till change time at 7.5K
miles. Now that it has nearly half a million miles, I expect to add
1 quart between changes. My 77 Olds 403 can go essentially
between changes at 2.5K without any extra oil. Bruce Roe
Other than all my VW / Audi products, the Northstars were the only cars I ever had that used oil. My old Pontiacs don't use any. My 66 Fleetwood used the equivalent of a quart every 12,000 miles, but most of that was rear main seal, and all of that was in the drip pan under the car. Rear main was replaced last week so now no leaks at all from the car.
I use 10w30 Valvoline VR1
Quote from: James Landi on June 04, 2021, 07:47:37 AM
...... Years ago, an "acceptable floor" on oil consumption was 500 miles per quart.
I feel that any engine that burns that "Acceptable" amount of oil, even if it a 2 stroke, should be taken off the road and not be allowed to be driven, anywhere.
Any amount between oil changes when new, should have the engineers and designers sacked.
My own older cars don't use more that a Quart of oil between oil changes, with these changes at 10,000 Kilometre intervals.
Bruce. >:D
"Any amount between oil changes when new, should have the engineers and designers sacked."
Bruce,
I hear you, and I have absolutely no argument with your assertion. My comment was a recollection of a "data point" from many years ago when car manufacturers and consumer advocates and litigators were fighting battles about such poorly engineered engines that you reference. I'm old enough to remember, vividly, cars that spewed long trails of blue smoke, and folks whose cars were surrounded by noxious blow-by at stop lights, as well as the smell of unregulated exhaust output in the air. In coming decades, the internal combustion engine will fade into obscurity as technological advances cause them to be obsolete. My suggestion for this gentleman is simply to use the oil recommended by GM, as there is no special oils that will make any difference, and frankly, as you know, there are "special additives" that can do additional damage. Happy day, James
I have to agree with James and Bruce. I worked at Cadillac on the 4.6L Allante and 4.0L Aurora in 1990-91. One of the reasons I left as they decided to hire on contract engine designers ahead of the fuel injection calibrators like me. Not sure many people know that Cadillac ordered Oldsmobile to hand over the prints to the Quad 4. The Northstar was based on a V-8 version of that. One of the engine designer clowns came in and presented to my group that as the Nstar was twice the size of a Quad 4 it was acceptable in his mind to have it use twice the oil. Quad 4 was a quart per 2k miles, N* 1K. He also was saying it would be ok to have the PCV off the left end of the head. If you took a long right sweeper it filled the PCV pipe with oil and chug through the motor and out the exhaust. I nearly walked out of that meeting.....