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Northstar oil consumption


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Hi I have an 2002 deville dts with 142000 miles that consumes an crazy amount of oil what year of the northstars 4.6l engines did they stop with the oil consumption problem, wouldn't mind engine swaping with that year

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:welcomesmiley:

How are you measuring consumption?

Are you using conventional (dino) oil or synthetic?

Have you owned the Cadillac since new? How has it been maintained?

Bruce

2016 Cadillac ATS-V gray/black

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Please answer Bruce's questions because this will tell us what we are working with and perhaps why the car is burning oil.

Usually when a Northstar burns oil the rings are stuck. There is a dealer treatment for that but the instructions for using it must be followed correctly.

I have some thoughts that will work on most cars. The first thing to do is to check the PCV valve and make sure it's not stuck. Also, the oil level on a Northstar doesn't need to be any higher than about 1/2 quart (liter) below the full mark on the dipstick. If you put any oil above the full mark, the car will foam it up and it will go through the PCV valve and the car will burn it. Also, I have a prescription that will work for most oil-burning Northstars:

  • Change the oild to a good grade of 10W-30 oil (or, if you are using 5W-30, that's OK too).
  • Fill the tank, from 1/4 tank or less, with premium gas.
  • Take a 500-mile (800 km) trip on a highway that allows maintaining at least 55 mph (90 kph).
  • Floor the accelerator and let it shift out of second gear at about 80 mph (125 kph) once or twice, if and where this is safe and legal.

There are others that will recommend a treatment that can be done in a low-traffic 50 mph (80 kph) zone, called the WOT treatment (for wide-open-throttle) but I like the gentler method that includes a little ride in the country.

CTS-V_LateralGs_6-2018_tiny.jpg
-- 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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Ditto on Jim's method. to many, it may seem that will not make any difference, but don't underestimate the benefits of a nice long drive for a car that may have been subjected to short stop & go driving most of it's life. Especially IMO for the 90's era N*'s -I wouldn't want my fine threaded headbolts to be subjected to the stresses of a WOT.

Although, I can see this thread turning into an oil discussion - it's been some time since that topic has come up.

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To answer one of the things on the original post, and emphasize my in-passing remark "Usually when a Northstar burns oil the rings are stuck" - Northstars never did have an oil-burning problem. The "design center" was a quart every 2000 miles with warranty work called for if the car burns more than a quart every 1000 miles, just like all other big V8 engines since, well, 1949. With an oil capacity of 7.5 quarts, a DIC warning at 5.5 quarts, and an engine designed to work well with three quarts in it, it's hard to imagine a problem being caused by oil consumption in a Northstar. Most people never add oil between servicing sessions, which are 3000 miles to 12,000 miles apart, depending on conditions and the owner's inclinations.

But, a combination of bad driving conditions and cheap oil over a long period of time can result in a case of stuck rings, just like in any car. Early Northstars were more susceptible to stuck rings than later Northstars. But in nearly all cases a case of stuck rings is dealt with without a lot of trouble or expense.

About ten years ago, my Northstar developed stuck rings, suddenly. I solved it by changing where I had my oil changes done.

CTS-V_LateralGs_6-2018_tiny.jpg
-- 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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Starting with the 2000 model year, the Northstar had redesigned rings and pistons to deal with the oil consumption. You need to check the oil when the oil is hot or you'll get a false low reading on the stick. If you're adding oil to the FULL mark on the stick when the engine is cold, you're overfilling the crankcase and the excess oil will be churned up by the crankshaft, vaporized, and burned through the PCV system.

Check the oil hot, adjust as required and then drive the car until the CHECK OIL LEVEL message comes on on the information center. Add ONE quart of oil, record the mileage. Drive the car until the CHECK OIL LEVEL message comes on; again, add one quart, record the mileage, then subtract the earlier mileage reading. This will be the "miles per quart" reading that can be used to evaluate the oil consumption. Note, this may take a few months to obtain the data.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I have a 2002 Deville service manual on my DVD. One thing I found in the list of TSBs and bulletins that applied to this car was the famous #02-06-01-009C, Higher Than Expected Oil Consumption (Clean Piston Rings) - (Oct 23, 2003), which I made a PDF file of and put on my web site. Link:

http://jameskbeard.com/jameskbeard/Cadillac_Files/02-06-01-009C_Oil_Consumption.pdf

There is another bulletin about oil consumption that may apply here but previous posts have already addressed its main points: don't over-fill, check the oil properly, normal oil consumption is a quart every 2000 miles, and if it does burn oil, check the PCV valve, oil leaks, etc.

The engine treatment referred to in the TSB is NOT the same as the top-end cleaning technique because the solution used is different, the technique is different, and the amount of time that the solutions are left in the cylinders is different - which is updated from a similar older bulletin that I knew of from about this same time. The solution must be left in the cylinders between two and three hours. Less than two hours results in incomplete treatment, more than three hours results in the dissolved shellac settling back down into the rings.

Make sure that you print out the TSB for the service manager if you decide to ask about this treatment. I had this done on my car, and the treatment at that time said not to let the solution stay in the car longer than one hour. The tech let it stay for four and a half hours. That's what the service manager told me, so it's clear that they hadn't read the TSB and didn't have a clue that this would make the car worse than before the treatment. I solved the problem later by changing where I got the car's oil changed; two 5W-30 Mobil 1 oil changes later, oil consumption was normal, about a quart every 2000 miles.

CTS-V_LateralGs_6-2018_tiny.jpg
-- 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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I guess I am one of the lucky ones....

Not all of them use oil.

I have never needed to add any oil between changes, except for the first one.

I go 7,000 to 9,000 between changes.

I used to do the 3,000 mile thing when I first bought it... now I do it at about 25% to 30% oil life remaining, on the Oil Life Monitor.

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