Oil Consumption

[TonyMazz]

Just wondering what seems reasonable. I am currently running 5W-30 Mobil 1 synthetic oil and using the GM OLM to determine when to change the oil.

 

Currently do alot of highway, no towing, in Wisconsin, and have so far 8000 miles on this oil and notice that I am down 1/8 - 1/4 quart. Expect to have the oil light come on in the next 1000 miles (based on previous occasion).

 

I know what the bullentins say...i.e. 1 quart/2000 miles is reasonable, but am wondering what others have seen...

 

Truck has 37,500 miles on it so far....

[Dave in Mpls]

I haven't run my 5.3 long enough on M1 to establish any kind of consumption rate, but I certainly wouldn't be concered about 1/8 - 1/4 quart in 8000 miles. That said, while the oil can run to 10,000 miles or longer, I'd be replacing the filter every 5000 miles max. Your mileage may vary.......

[KB06YUKONXL]

Mobil1 has changed their formula and is no longer a 100% PAO based Group IV synthetic oil. It is now a Group III basestock oil and lots of people are seeing consumption increases in a variety of vehicles. In 8,000 miles you have very little. Some guys report 1 qt in 5000. Try some Pennzoil Platinum from Wallyworld for $3 less than M1 and see what happens. PP is a Group III as well but has Shell basestocks which are considered better. FYI, I am running M1 but will try PP when my stock runs out.

[vxaxv17]

I am losing about 1qt every 2000 miles. I consistently have to add another qt before my next 3000 mile oil change. Think i'll be replacing my pcv valve. This is an 02 2500hd with the 6.0l. It has 60k miles.

[95Sierra2500]

1. IIRC M1 is still a group IV synthetic (real M1 that is, not the extended-life or high-mileage oils).

2. The dealers around here tell me that for an engine to burn 1 quart every 3000 miles is normal and not to worry about it. I honestly say that's BS and would be looking for the leak, and if there aren't any external ones and the PCV valve is okay, then I'd be rebuilding an engine. 1/4 of a quart in 8,000 miles, though, I wouldn't worry about at all.

[yukon4wd]

I use M1 synth, the computer normally tells me to change at about 5,000 miles Odo reads about 25,000. Last change I used about 3/4 quart for those 5,000 it seemed high to me. Since up till then I never used enough oil to even need a top up between changes.

[GM-Tech]

Subject: Information on Engine Oil Consumption Guidelines #01-06-01-011B - (08/08/2005)

 

 

 

Models: All 1998-2006 Passenger Cars and Gasoline Powered Light Duty Trucks Under 8500 LB GVW (Including Saturn)

 

 

 

 

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This bulletin is being revised to update the model years, models affected, and oil level check information. Please discard Corporate Bulletin Number 01-06-01-011A (Section 06 -- Engine/Propulsion System).

 

 

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All engines require oil to lubricate and protect the load bearing and internal moving parts from wear including cylinder walls, pistons and piston rings. When a piston moves down its cylinder, a thin film of oil is left on the cylinder wall. During the power stroke, part of this oil layer is consumed in the combustion process. As a result, varying rates of oil consumption are accepted as normal in all engines.

 

Oil Consumption

The accepted rate of oil consumption for engines used in the vehicles referenced is 0.946 liter (1 qt) in 3200 km (2000 mi).

 

Important: Certain 2006 models have a new GM Extended Warranty. Please refer to the appropriate Owner's Manual for warranty information.

 

This rate only applies to personal use vehicles, under warranty, that are driven in a non-aggressive manner and 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.

 

Important: This rate does not apply to vehicles that are driven in an aggressive manner, at high RPM, high speeds, or in a loaded condition (for trucks). Oil consumption for vehicles driven under these conditions will be more.

 

Many factors can affect an owner's concern with oil consumption. Driving habits and vehicle maintenance vary from owner to owner. Thoroughly evaluate each case before deciding whether the vehicle in question has abnormal engine oil consumption.

 

 

Gasket and External Leaks

Inspect the oil pan and engine covers for leakage due to over-tightened, damaged, or out of place gaskets. Inspect oil lines and fittings for signs of leakage.

 

 

Improper Reading of the Oil Level Indicator (Dipstick)

Verify that the dipstick tube is fully seated in the block. When checking the oil level, make sure the dipstick is wiped clean before taking an oil level reading and fully depress the dipstick until the shoulder bottoms out on the dipstick tube. The dipstick should be the proper part number for the engine/vehicle that is being checked.

 

 

Not Waiting Long Enough After Running Engine to Check Oil Level

Some engines require more time than others for the oil to drain back into the crankcase. To assure a sufficient amount of oil has drained back to the crankcase, and an accurate reading can be obtained, the vehicle should be allowed to sit for at least 15 minutes, after the engine has been shut off, before taking an oil level reading. In order to ensure accurate results, the temperature of the oil should be close to the same temperature as the last time the oil level was checked.

 

Important: This does not apply to 2006 Corvette ZR1 equipped with the 7.0L LS7 engine (dry sump). Follow the instructions in the Owner's Manual for checking the oil in this application.

 

 

Improper Oil Fill After an Oil Change

Following an oil change, verify that the proper amount and type of oil was put in the engine and that the oil level on the dipstick is not above the full mark or below the add marks. Refer to the Owner's Manual or Service Manual for information on recommended oil quantity, viscosity, and quality.

 

 

Aggressive Driving, High Speed or High RPM Driving

Aggressive driving and/or continuous driving at high speeds/high RPMs will increase oil consumption. Because this may not always be an everyday occurrence, it is hard to determine exactly how much the oil economy will be affected.

 

 

Towing or Heavy Usage

Towing a trailer will increase oil consumption and may cause oil consumption to fall below the normal accepted rate referenced in this bulletin for an unloaded vehicle in a personal use application. Large frontal area trailers will further increase the work required from the engine, especially at highway speeds, and thus increases the rate of oil consumption.

 

 

Crankcase Ventilation System

Verify that the positive crankcase ventilation (PCV) system is operating properly. Blockages, restrictions, or damage to the PCV system can result in increased oil use.

 

 

Oil Dilution (Fuel and Water)

On vehicles that are usually driven short distances, less than 8 km (5 mi), especially in colder weather, unburned fuel and condensation generated from cold engine operation may not get hot enough to evaporate out of the oil. When this occurs, the dipstick may indicate that the oil level is over-full. Subsequent driving on a trip of sufficient length to enable normal engine operating temperature for 30 minutes or more, in order to vaporize excess moisture and fuel, may give the customer the impression of excessive oil consumption.

 

 

Engine Temperature

If an engine is run at overheated temperatures (see Owner's Manual or Service Manual) for more than brief periods, oil will oxidize at a faster than normal rate. In addition, gaskets may distort, piston rings may stick, and excessive wear may result. Verify that all cooling system components are in proper working order.

 

 

Engine Wear

Piston scuffing, excessive piston-to-wall clearance, tapered or out of round cylinders, worn, damaged or improperly installed valve guides, seals and piston rings will all cause an increase in oil consumption.

 

Measurement of Oil Consumption

Engines require a period of time to BREAK IN so that moving parts are properly seated. Therefore, oil economy should not be tested until the vehicle has accumulated at least 6400 km (4000 mi). An exception would be allowed only if an engine is reported to be using more than 0.946 liter (1 qt) in 1600 km (1000 mi).

 

Verify that the engine has no external leaks. Repair as necessary.

Verify that the engine is at normal operating temperature (see Owner's Manual or Service Manual).

Park the vehicle on a level surface.

Wait at least 15 minutes, after the engine is shut off, before checking the oil level to make sure that the oil has had time to drain back into the crankcase.

Verify that the oil level is at, but not above, the full mark on the dipstick, and that the proper viscosity and quality oil are being used as recommended in the Owner's Manual.

Record the vehicle mileage, date, and exact oil level on the form included in this bulletin.

Ask the customer to verify the oil level, each time the vehicle is fueled, following steps 1-6 and return the vehicle to the dealership if the oil level is found at or below the add mark, 0.946 liter (1 qt) low. If the oil level remains above the add mark, the customer should continue to operate the vehicle and verify the engine oil level until 3200 km (2000 mi) has accumulated before returning to the dealership for a final evaluation.

If the final evaluation shows that the engine uses more than 0.946 liter (1 qt) in 3200 km (2000 mi), follow the published symptom diagnostics as described in the appropriate Service Manual. If the oil consumption test shows that the engine uses less than 0.946 liter (1 qt) in 3200 km (2000 mi), explain to the customer that their engine meets the guidelines for oil consumption.

[yukon4wd]

Subject: Information on Engine Oil Consumption Guidelines #01-06-01-011B - (08/08/2005)

 

...

Oil Consumption

The accepted rate of oil consumption for engines used in the vehicles referenced is 0.946 liter (1 qt) in 3200 km (2000 mi).

...

 

<{POST_SNAPBACK}>

 

 

 

OK, so I guess I have nothing to worry about then (except for the price I am paying for oil).

 

BTW thanks for the post, very useful information.