: Northstar losing oil

07-05-05, 11:36 AM
A friend at work has an 00 Seville SLS with the 32V Northstar. It has 62K miles and is losing oil. She claims there is no leakage in the garage. She is adding 2 quarts at a time (when oil light comes on). I asked it she noticed any blue smoke, she said not to her knowledge. She is going to watch it more carefully now. What could be wrong? Rings, valve stem seals? I admit I know nothing about these Northstars. Any help would be appreciated.



07-05-05, 12:27 PM
The Northstars do burn a little oil. Ask your coworker how often she has to add oil. If it's every 1000 miles or so, that's about the norm. If it's more often than that, have her get the thing on the highway and put the pedal to the floor on the onramp until about 70-80 MPH (only if it's safe, of course). If she sees any black smoke out the tailpipe during this process, it's blowing carbon off the piston rings and that will help with excessive oil consumption to some degree, but it will probably still consume some oil. She can do that process (Wide Open Throttle or WOT) several times to start, then once a week or as often as she wants to do it (the more the better) to help keep consumption low. She's not going to hurt the engine at all by flooring the pedal.

She should NEVER overfill the oil system. Two quarts might be too much. If the oil is at room temperature and she's filling it to the top of the hash marks, it's overfull. It will expand when it heats up and can vaporize and get sucked into the PCV system. If two quarts puts it at the top of the hash marks, have her cut it down to 1.5 quarts. She should be using a good quality 10W-30 motor oil rated SJ or better with the Energy Conserving mark in the seal.

Good luck!

07-05-05, 12:27 PM
How often does it "lose" oil? The N* is designed so that a quart every thousand miles is perfectly normal, even when brand new. If she's putting two quarts in between oil changes, then its fine. Have her, or you, if you can talk her into it, go out and do some WOT (Wide open throttle) accellerations...second gear, stomp on it to about 60 or 70, then let the engine braking slow it back down to 40 or so and do it again...keep doing it until the black smoke stops coming out of the exhaust, and it'll run better and oil consumption should go down. Enjoy it, and tell her not to worry!

07-05-05, 12:32 PM
Go to the top left of this page and click on "Technical Archives". Read up on oil consumption. As Mcowden said, it is probably normal and the "problem" is only perceived. Once she understands it, she won't worry about it.

07-05-05, 12:35 PM
I see you're new around these parts, pardner. :) Read up on some of the threads here on "WOT" and "Northstar Oil Issue". Basically, the N/Star ( N* ) engine loves to be driven hard. Babying it around will not allow the rings to seat well and will cause more than usual oil consumption. I'm betting, since you mention "her" as the owner, that she doesn't push it all that often.

Have her (or better yet, have YOU.. ) take to the nearest freeway on-ramp, pull it into 2nd gear, and floor it. When it hits 70 or so, and shifts up to 3rd, let up on the throttle and let her coast back down to about 50. Then nail it again. Repeat a few times. If you see smoke out the rear end, its working.

The "WOT" tuneup is recommended by all knowledgeable people on the board, including Cadillac powertrain engineers and such. The N* has a very aggressive cross-hatch pattern on the cylinder walls, and too much light duty will never allow the rings to get seated well.

The harder you flail these babies, the better off they are. There's a good chance that once the engine is broken in and fully functional, the oil consumption will drop to 1/2 to 1 qt every 1000 to 1500 miles. There is a certain amount of BUILT IN oil consumption in these engines, it is perfectly normal. Two bucks worth of oil every thousand miles or so, and many N* routinely hit 150 - 200K miles.

07-05-05, 06:03 PM
Guys, I never realized that the Northstar had an oil consumption issue. Like I said before, I know nothing about these engines, but they are very interesting. I will forward this info and the email that Mario sent me to her. She did make the comment that she never drove it hard. Now she will have a reason to have some "fun" with the car.

Much appreciated,

07-05-05, 06:21 PM
ahhhh...mcowden beat me to it...both of posted in the same minute, and said pretty much the same thing... :)

07-05-05, 07:57 PM
You guys really need to understand and accept that some level of oil consumption is fine and good and is there on every engine. Look at the BMW, Mercedes, Lexus, Porsche, etc.... literature. The Northstar is in with some pretty pricey company with it's "oil consumption" habit. ALL of the aforementioned competition have statements in public to the effect that oil consumption of as much as 1 quart per thousand miles is considered acceptable and is not a sign of an engine problem. All of them say this if you look. Everyone with high performance engines treads the line between enough oil consumption to keep the engine alive at continuous full throttle and little enough consumption to satisfy the customer. There is some variability in all engines and, though not designed to use 1 quart per thousand miles some will due to production tolerances, variability of the operating schedule, differenct breakin procedures, different oils, etc....

BMW had such an issue with some of their M-series engines that they said in the owners manual to check the oil level at EVERY gas stop on the autobahn as oil consumption at high load could exceed the reserve capacity in the sump for each tankful if the oil level were not topped off. And the engines are fine......they just use oil....and they cost way more than $40K.

...:worship:And this guy REALLY KNOWS the Northstar.... and there's more... here's the "why:"

The issue in the variability in oil consumption is not the "clearances" or "tolerances" at assembly.

The issue is some variability in the cylinder wall surface finish in the final honing of the block. There is a fairly tight range of surface finish requirements on the finish but within the narrow range of the surface finish on the cylinder walls there can be considerable variability in the oil consumption. Keep in mind that the more aggressive the hone pattern is the more oil is retained on the cylinder walls. This is good for lubrication and ring sealing but it does lead to some oil consumption. It is the nature of the beast when designing a high performance engine. It isn't a matter of poor quality control or loose tolerances or anything. The things like that...being piston fit, ring gap, cylinder diameter, etc.... are all controlled very tightly. The variability is strictly in the ring interaction with the cylinder walls and the surface finish of the cylinder walls.

The bright side of this is proven by the the repeated posts of folks taking the heads off at well over 100K and discovering that the cylinder walls look like new, that the rings/pistons virtually never wear out, the original hone pattern is still visible in the cylinder walls, there is absolutely NO wear ridge at the top of the cylinders, etc. The aggressive honing pattern is the way to go but it does lead to some oil consumption and some variability in oil consumption combined with the low friciton/low tension rings used for better performance and better fuel economy.

The furor over oil consumption is just completely overblown. Putting a fresh quart of oil in occasionally is good for the engine anyway as it adds a fresh spike of the antiwear additives in the fresh oil to the sump. I feel that the longevity offered by the design totally offsets the oil consumption seen. Oil is inexpensive and easy to add. Put it in and run the snot out of it and worry about something else. The thing that needs changing is the mindset that "oil consumption is bad" or that "oil consumption means that the engine is about to fail". It does not mean that. If an engine ran with absolutely no oil consumption and then suddenly started using a lot I would be concerned. Continuous oil consumption without tailpipe smoke that is regular and repeatable is nothing to be alarmed about. Honestly, I think a lot of engine engineers are surprised at the public outcry about oil consumption in some high performance engines like the Northstar. Every manufacturer has this variability in oil consumption to one degree or another. BMW specifically calls out to check the oil at every fuel stop in some of their M series engines as the oil consumption can be great enough between fuel stops to cause the sump to be low..!!! Not that every engine does that but some do with absolutely nothing wrong.

It is true that all the oils have to meet the same standard....but....there can be some difference in oil consumption between different types and different brands of oil. Seen it happen. Particularily synthetic oils seem to exacerbate the oil consumtion issue in the earlier model Northstar engines.

07-06-05, 08:53 AM
ahhhh...mcowden beat me to it...both of posted in the same minute, and said pretty much the same thing... :)

Spyder was in the lead in the long stretch, but I kicked in the afterburners and it was a photo finish. Unfortunately I burned up the keyboard in the process... :D Good to know we agree!

11-05-05, 01:28 PM

I`m from Germany, my English is not perfect, but I hope you`ll understand something :duck:

My N* had burned to much oil, too. 1-2 Quart to 500 miles.

Now I had test the "hard drive" method, in Germany we have no speed limit on highways, so I test it every day for a week for 30 miles on highway with 150 mph.

Ouuuuu:bonkers: it burns gasoline...... in Germany we have to pay for a gallone about 7 Dollars....:rant2:

Know I the "oilloosing" is away. N* needs only a quart to 3000 miles.

__________________________________________________ _____________

I search some people in USA, who would send me some parcels to germany with USPS.

The problem: Most Part dealers in the USA don`t ship international.

I can pay it with credit card and let ship it to you, then I pay per paypal the rate for shipping to germany and a little bit above. Nobody works for nothing.

Who can help me?

11-06-05, 03:26 AM
That person really needs to get on the gas pedal more. It really bugs me to no end when I see that same old white 2004 STS being driven by an 80 year old grandpa 50 mph on the highway.

11-06-05, 05:35 AM
I search some people in USA, who would send me some parcels to germany with USPS.
The problem: Most Part dealers in the USA don`t ship international.
I can pay it with credit card and let ship it to you, then I pay per paypal the rate for shipping to germany and a little bit above. Nobody works for nothing.
Who can help me?
I'd take you up on that offer if I had any idea how to ship parts overseas...

11-06-05, 10:40 AM
Shipping overseas requires a freight forwarder/customs broker. UPS has recently bought out Emery World Wide and is now called Menlo Forwarding. I used them to do all my overnight shipping to Germany, England and Japan. My fiance used to be the international manager for them. I'll find out whats involved for sending smaller packages and let you know.

11-07-05, 01:03 AM
To Irebroff: I'll see if we can help you with parts for your STS. Normally we only sell Cadillac Allante' parts, and we have shipped to Germany, France, the Netherlands, Spain, Australia, and England. I am familiar with the Cadillac STS also since we have owned both a 1994 and a 1998. You can e-mail me directly at allantesource@prodigy.net .

05-20-07, 06:28 PM
I have a 1998 sts cadillac,and i was wondering why only when i start the engine it vibrates blow out a lot of blue smoke,then the engine idle smooth's out the blue smoke disapear,while im driving you don't ever see the blue smoke,only until i turn the engine off then start it back up.

05-20-07, 09:01 PM
Sounds like valve seals. Not a common complaint here.

Tommy Deville
05-21-07, 02:25 AM
2 quarts of oil is the norm when the oile light starts to flicker, it should be ok since there is roughly 6 quarts left in the motor.
I usally got hough 1 to 2 quarts every 1000 to 1200 miles depending on how & where I drive, mostly city/suburb driving for me, short distances.

05-21-07, 02:55 AM
I never had any problems with my 97 Northstar. I did, however, solve any potential headaches by selling it and landing on an 04 CTS with 3.6. Really have not driven the car much yet. It is not a SDV or DHS, DTS. Time will tell, although I will eventually go back to a newer Northstar. Long wheel base too. Nice, fast, comfortable.

I rode in the back seat of my CTS (sport package), and it felt like my son's 96 Buick Skylark. Just like riding in a VW. Certainly, the CTS has almost every option GM offered, but I am more interested in comfort and ride.