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Excess OIl Consumption on Northstar engines
fraudfighter
Member Posts: 9
I am researching the excess oil consumption problem with Northstar engines. Saw some posts here back in 2001 but none since. It is apparently a very wide spread problem - 3 technical service bulletins posted thus far and no known fix for certain models.
Anyone have recent input on this?
Anyone have recent input on this?
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Comments
I'm aware of a "stripped head bolt" problem they had in earlier models and I've seen a number of leaky oil pans also (and that's a major repair on those)
320hp is not high performance? Funny.... it's right there with other manufacturer's so-called high performance motors that they are putting in luxury cars these days.
It currently has an IMSA team running some pretty serious stats.
Those race cars probably don't burn as much oil as a Seville or Deville, though, or the Escalade with the 6.0, for that matter.
Anyway.... my wife's 10 year old Northstar doesn't burn or leak oil. But it is quite powerful - a very fine powerplant, IMO.
De-carboning the engine, with cleaner pulled into the fuel system seems to work sometimes to reduce the oil burning....
Higher than Expected Oil Consumption (Clean Piston Rings)
1996-2000 Cadillac Concours
1996-2002 Cadillac Eldorado
1996-2003 Cadillac DeVille, Seville
with 4.6L Engine (VINs Y, 9 -- RPOs LD8, L37)
This bulletin is being revised to add parts information. Please discard Corporate Bulletin Number 02-06-01-009B (Section 06 - Engine).
VIN Breakpoints
Model Year * Model * VIN Breakpoint
1996-2002 * All Above * All
2003 * DeVille * Prior to 3U213641
2003 * Seville * Prior to 3U215818
Condition
Some customers may comment on higher than expected oil consumption. The typical customer with this condition comments on consumption in the range of 0.946L (1 qt) of oil used in 1600-2250 km (1000-1400 mi) of operation. The oil consumption rate and possible oil consumption areas, as per Corporate Bulletin #01-06-01-011 dated March, 2001, should be verified prior to performing the ring cleaning procedure below. The standard for acceptable oil economy and the method for determining oil economy are outlined in Corporate Bulletin #01-06-01-011.
The following text is referenced from Corporate Bulletin #01-06-01-011 for your convenience.
Oil Consumption:
The accepted rate of oil consumption for engines used in the vehicles referenced is 0.946L (1 qt) in 3200 km (2000 mi). This rate only applies to personal use vehicles, under warranty, maintained in accordance with the appropriate maintenance schedule, with less than 58,000 km (36,000 mi), or 80,450 km (50,000 mi) for Cadillac, driven at legal speeds in an unloaded (for trucks) condition.
Cause
Although there are several reasons for less than expected oil economy described in Corporate Bulletin #01-06-01-011, one area not covered is reduced sealing ability of the rings. Through normal usage, combustion chamber deposits may build up to the point that the movement of the rings could become restricted and prevent the rings from wiping all of the oil off the cylinder walls and allowing it to be burned in the combustion process.
Correction
A new ring cleaning process has been developed to restore the function of the rings. Once the possible oil consumption areas in Corporate Bulletin #01-06-01-011 have been eliminated, this cleaning process should be performed. If the oil economy has not improved to 0.946L (1 qt) in 3200 km (2000 mi) after cleaning, it may be necessary to replace the piston rings. Be sure to install the second compression ring notch side down. If the vehicle is a 2000 to 2003 with an oil consumption concern with less than 25,000 miles on the vehicle, then skip the cleaning process and install the new rings.
Important
It is critical in this cleaning process that the piston and ring cleaner remain in the cylinders for a minimum of two hours to fully clean the components. The cleaner solution must be removed before three hours. Additional soak time does not increase the effectiveness of this process. If solution with the dissolved deposits remains in the cylinder too long, it will soak back into the rings and cause them to stick again. If this happens, the oil economy will be reduced even further.
An oil economy test should be performed after the cleaning process is completed. Before starting this test, the full oil level on the dip stick should be noted and shown to the customer. The correct oil fill is 7.1 L (7 ½ qts) with a filter. The dipstick should not be read for at least 15 minutes after the engine has been shut off for an accurate reading. Typically, the oil level shown on the dipstick is in the second or third section above the add mark. If the indicated oil level is at the MAX mark, there is approximately 0.47 L (½ qt) too much in the system and it will be scavenged by the PCV system quickly. When performing this test, the most accurate results may be obtained by having the customer drive the vehicle until the CHECK OIL LEVEL message appears and then returning the vehicle to the dealership to determine the oil economy. No damage will be done to the engine by operating it until the Check Engine Oil Level message is displayed. There is 4.7 L (5 qts) of oil still in the system.
Field feedback has indicated that vehicles that have been operating at a high consumption rate (0.946L (1 quart) of oil in 1600 km (1000 mi) or less) for greater than 32,000 km (20,000 mi) may need a second application of the piston and ring cleaner to adequately clean the rings. If a second application of piston and ring cleaner is necessary, it can be done immediately after vacuuming out the first application.
Maybe you should try BMW's. Their M5 manual tells the driver to check his/her oil at every gas fillup. Now that's oil consumption!
Hmmm...........
But I understand this was corrected later on during a redesign process.
Given that most people don't drive Cadillacs at redline I don't think the problem could be attributed to high performance driving in this case. It is usually at extreme revs that engines of all types want to pump some oil through the rings.
From the little research I've done, it seems like a manufacturing defect or design defect that has been worked out of newer models---but I can't say as I've seen any "fix" that seems to really satisfy all the owners affected.
But I haven't dug into it that much, so maybe this topic can help us clarify the model years affected, the fixes attempted, and the success rate.
issues at the top of the line for GM tend to be noticed, and reacted to, hence all the changes implicated in the advisory.
be nice if it also said, "the following type of driving has been associated with the condition... so don't do it." whether it involves driving choices that result in tire life of 5000 miles, or driving choices that include never revving over 827 rpm