: High oil consumption (1 quart/week!!)

11-01-06, 07:28 AM
The 2000 SLS. I check all the car's fluids weekly. Every time I check the SLS it is below the add mark. This is every single week, which is about only 100-200 miles. So as a test, one week when I noticed it was low, I didn't add any oil that week. The next week, the dipstick had only one drop of oil on it at the bottom. So it seems like it lost another quart!

Weekly, the engine will take 1 quart, and then puts it near the top (I don't fill it exactly to the top as per the technical archives). My 95 Eldorado is normal, 1 quart of oil every 1000 miles or so.

What should I do next?

11-01-06, 07:35 AM
1 qt per 100 miles sounds like a pretty good leak to me.

I take it this started suddenly?

Is it leaking by the filter maybe after the last oil change?

11-01-06, 11:24 AM
A qt. per 100 - 200 miles should either be smoking like an old steam engine or leaking like a sieve (sp?) and easy to locate.

11-01-06, 12:40 PM
Sounds like my old pickup. I pull into the gas station and say "Gas, oil, and water; a gallon of each. Just pour the oil on the fender because it's going to leak on the ground anyhow."

11-01-06, 01:13 PM
Inspect the engine for leaks, top to bottom. if it's not leaking it's burning it. pull the plugs and look for crusty build-up.

11-01-06, 11:36 PM
One to try... jack up the front of the car evenly, and use a cinderblock or something (on a garbage bag so as not to damage the mat) to prop the accelerator at a normal driving RPM (1500 will be great). Look around the oil filter for leaks. There are two o-rings at the back of the adapter plate that can leak, and I have seen these cars with one bolt loose on the adapter plate, causing a similar leak. Usually it won't be so bad as to leak at idle, hence the RPM increase. From idle to about 15-1800 is the single largest increase in oil pressure to RPM ratio.

Look at the oil pressure/temperature sensor too. They can be loose (seen that one too). Understand that they have a pipe thread, which is tapered, so won't simply tighten until it stops, they get progressively tighter. Just use good judgement dealing with them. As far as tightening goes, it's a real pain with the adapter still on the car. The best thing to do is to try to give it a twist with some med. large channellocks. If it turns at all easily, then disconnect the wire and tighten it, then reconnect it. Do NOT grab it by the plastic sensor body. Mine cracked lengthwise in that place and made a huge mess of the car's underbody on a highway drive. It also dumped about a quart and a half of oil over the course of 25 miles. My sensor was original and never tightened in this manner.

Also, this one will sound totally braindead, and I am not intending insult, but be sure that the oil filter is tight. I never use tools to tighten them, I give it a good spin (a few drops of oil on the threads instead of just the gasket helps with that), turn it as far as it turns reasonably easily, then give it a half a turn or so by hand. It should still be possible to tighten by hand just a little bit more, but they tighten up a bit so don't. You should be able to JUST BARELY remove it by hand at your next oil change, assuming it's clean and dry.

11-02-06, 08:52 AM
Thanks for the advice. The bad thing is there are no leaks or smoke for the SLS. Left it in the driveway overnight all the time, and nothing under the car, not even a wet spot. Starts up and WOTs with no smoke at all. I can only think the leak is from actual driving, so I wouldn't see it in the driveway.

Car is becoming a nuisance. Lots more trouble then my Eldo, and my Eldo is way older, has more miles, and works a lot harder (I am a lead foot, and the whole town knows it).

11-02-06, 09:05 AM
If it's leaking while driving the engine would still be wet with oil. If it is wet (with oil) clean it off completly and drive it a short distance and recheck. The oil is going somewhere, it doesn't evaporate.

11-02-06, 09:52 AM
There are oil leak detector kits at NAPA that put a dye in the oil that makes seeing the leaks easier. Worth a try.

11-02-06, 10:24 AM
I agree.:thumbsup:

11-03-06, 11:10 AM
has anyone ever gotten 150k on their northstar, with no problems?wish I read this site before buying a caddy.

11-03-06, 12:58 PM
Sure they have - you rarely hear about them on forums such as this because people rarly seek out a forum to brag how trouble free their car is.

11-03-06, 01:35 PM
has anyone ever gotten 150k on their northstar, with no problems?wish I read this site before buying a caddy.
What problems do you have with yours?

11-03-06, 01:43 PM
Another thing you may want to check, under the intake manifold cover.

I was checking for fuel leaks recently and discovered about a half inch of
oil in the bottom of the intake, I cleaned it up and made sure the PCV system
was clear.

11-03-06, 04:04 PM
What problems do you have with yours?
See post #90


11-03-06, 04:20 PM
Oh, I see. . :crybaby:

09-27-07, 03:05 PM
I pull into the gas station and say "Gas, oil, and water; a gallon of each. Just pour the oil on the fender because it's going to leak on the ground anyhow."

dkoz...that's good stuff...

09-28-07, 10:14 PM
Jack up the car and put stands under the outboard ends of the engine cradle. Crawl under and, using a good flashlight, look at the oil filter area. Is there any -ANY- oil on the filter or the adapter or the pressure switch or ?? the oil cooler line connections?? 1 quart a week means there's a trail betwen your driveway and wherever you go. This isn't rocket science......if it's not leaking it, it's burning it. No other options.

10-12-07, 08:44 PM
Ok, I'm assuming you have checked for oil leaks, as you said you parked it on a surface where you can see leaks, and there was none.

This means it is 'burning' the oil.

Have you, and/or the previous owner 'babied' this car all its life?

If so, then the rings are stuck, carboned up. And oil is blowing by the rings and is being burned.

You need to do the old 'drive it like you stole it'. There is no need to do this from a total stop - a rolling start from 5 or 10 mph will be fine and will not stress the drive components so much. So, slowly rolling, on a nice straight stretch of road, with no police around, put the accelerator to the floor and keep it there. Until the motor upshifts to third gear. You will then be running about 80mph. Looking in your rear view mirror, you should see a cloud of black smoke. Let the car coast down, and do this again. Let the car coast down, and do it again.

Do this at least monthly. And I don't mean 'accelerate briskly. Keep it floored. All the way.

Your oil usage will drop significantly.

Premium grade fuel resists 'pinging', but it also carbons up the rings worse than a motor burning regular. A Northstar needs to be driven agressively on occasion to keep the rings from sticking.

Try it. You will like it.