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8.1 oil consumption


fluf71

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i have a 2002 chevy crew-cab with the 8.1 and allison transmission and it has been burning oil since i've had but is getting worse its now burning 2 quarts every 3000 miles just wander if anyone has any of the same problems and is there a fix for this already had the intake bolts replaced the was supposed to help according the the dealer but it did not thanks for all you help. :)

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Check out this link here about the GM limit on oil consumption for starts.

http://www.gm-trucks.com/forums/index.php?...l=8\.1+oil

 

Also the 8100 vortec engines don't have a PCV valve.

http://www.chevyavalanchefanclub.com/cafcn...ic,15701.0.html

"1) The 8.1 does not have a PVC valve. Makes me wonder how

the oil vapors are controlled. I realize the smaller V8 has one,

and its replacement helped with the issue."

 

Answer: The crankcase ventilation system has no serviceable components so routine maintenance of the system is not required. A closed crankcase ventilation system is used in order to provide a more complete scavenging of crankcase vapors. The air cleaner supplies the fresh air through a filter to the crankcase. The crankcase mixes the fresh air blow-by gases. This mixture then passes through a pipe/passage located in the intake manifold.

 

8.1L only

 

Some of the fixes for this is changing the manifold bolts as related to the ones in 2500 Avalanches.

http://www.chevyavalanchefanclub.com/cafcn....html#msg684947

http://www.gm-trucks.com/forums/index.php?...=manifold+bolts

 

Do a search here on manifold bolt and learn more about this.

 

Brian1

 

 

 

i ve had the manifold bolts changed and it hasent helped and i'm still :cheers: but am going throught the dealer oil consumption test right now so i'll se where that goes probalble nowhere but we will see thanks for all you help!! :P:D:crackup:

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i have a 2002 chevy crew-cab with the 8.1 and allison transmission and it has been burning oil since i've had but is getting worse its now burning 2 quarts every 3000 miles :cheers:

 

 

 

 

 

You need to read the complete GM tch article.

 

they stated that "one quart of oil per one hundred gallons of gas used driving was acceptable".

 

so 10 mpg equals 1 quart of oil per 1000 miles.

 

also talked about engine load being a fact or etc...

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If you pull the intake and look on the bottom you will see a port sticking down. This port is essentially the PCV valve. It sits right on top of the valley tray and sucks the oil that is splashed on to it. If you take a bent peice of pipe, with the opening pointing up towards the intake, and tack weld it to the port it will fix the oil consumption

 

 

 

 

 

This is the first time I've seen a reasonable explanation for the unusual oil consumption on the 8 liter. A quart in 1000 miles is rediculous! Thanks for the insight!

 

Farmpaw

 

It is apparent that nearly every 8..1L person I talk to has an oil consumption issue and GM has reacted the same way to all of us. It is normal up to 1 qt per 1000 or less miles. I don't think anyone would purchase a new vehicle if this was told up front.

 

Regard GM TECH 007 - Why didn't the dealer do this when they changed the manifold bolts on mine. Now what do I do?

 

Thanks,

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If you pull the intake and look on the bottom you will see a port sticking down. This port is essentially the PCV valve. It sits right on top of the valley tray and sucks the oil that is splashed on to it. If you take a bent peice of pipe, with the opening pointing up towards the intake, and tack weld it to the port it will fix the oil consumption

 

 

 

 

 

This is the first time I've seen a reasonable explanation for the unusual oil consumption on the 8 liter. A quart in 1000 miles is rediculous! Thanks for the insight!

 

Farmpaw

 

It is apparent that nearly every 8..1L person I talk to has an oil consumption issue and GM has reacted the same way to all of us. It is normal up to 1 qt per 1000 or less miles. I don't think anyone would purchase a new vehicle if this was told up front.

 

Regard GM TECH 007 - Why didn't the dealer do this when they changed the manifold bolts on mine. Now what do I do?

 

Thanks,

 

 

NEW INFORMATION YET TO BE VALIDATED:

 

I was told by a somewhat reliable source that on the 8.1L engines the valve covers had a design flaw in the internal baffling design. These baffles are there to route (splash etc) the oil back to the drain holes in the block. Apparently with the 8.1L the oil gets captured and pressurised in the cover not letting it drain back as it normally would and it ends up flowing into the exhaust valve.

 

I have not verified it yet and have heard there is a Service Document now out. This would explain why I have had oil consumption and smoking but, the plugs were looking ok.

 

Anyone in the know, have any information on the validity to this or is this really related to the manifold pipe idea noted above?

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If you pull the intake and look on the bottom you will see a port sticking down. This port is essentially the PCV valve. It sits right on top of the valley tray and sucks the oil that is splashed on to it. If you take a bent peice of pipe, with the opening pointing up towards the intake, and tack weld it to the port it will fix the oil consumption

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If you pull the intake and look on the bottom you will see a port sticking down. This port is essentially the PCV valve. It sits right on top of the valley tray and sucks the oil that is splashed on to it. If you take a bent peice of pipe, with the opening pointing up towards the intake, and tack weld it to the port it will fix the oil consumption

 

 

 

 

 

This is the first time I've seen a reasonable explanation for the unusual oil consumption on the 8 liter. A quart in 1000 miles is rediculous! Thanks for the insight!

 

Farmpaw

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I have seen it many times. It has to have correct flow or it will pull oil into the intake and burn it. Below is a bulletin that explains it and some other causes. The thing is that a PCV is the best cheapest thing to try next. I would give it a try. BTW, only use an AC/DELCO PCV. I have seen aftermarkets cause oil consumption.Document ID# 1370475

2002 Chevrolet Chevy K Silverado - 4WD

 

 

--------------------------------------------------------------------------------

 

 

Subject: Info - Higher Than Expected Oil Consumption (Greater Than 8500 GVW) #03-06-01-023 - (08/19/2003)

 

 

 

Models: 2000-2004 Chevrolet Express, Silverado, Suburban

 

2002-2004 Chevrolet Avalanche

 

2000-2004 GMC Savana, Sierra, Yukon XL

 

2003-2004 Chevrolet Kodiak C4500-C5500 Series Models

 

2003-2004 GMC Topkick C4500-C5500 Series Models

 

2003-2004 HUMMER H2

 

with Gasoline Engines and Rated at 8600 GVW and above

 

 

 

 

--------------------------------------------------------------------------------

 

Information on Engine Oil Consumption Guidelines

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 combustion process, part of this oil layer is consumed. As a result, varying rates of oil consumption are accepted as normal in all engines.

 

Oil Consumption

Oil usage has a direct relationship with the amount of fuel used. The harder an engine works, the more fuel and oil it will use. Therefore, oil usage as a factor of fuel usage is a more accurate indicator of acceptable oil consumption levels than vehicle mileage for vehicles at or above 8600 GVW.

 

The accepted rate of oil consumption for gasoline engines in vehicles at or above 8600 GVW is 0.946 liter (1 qt) within 379 liters (100 gallons) of fuel used. This rate only applies to vehicles under warranty, maintained in accordance with the appropriate maintenance schedule, driven at legal speeds and within design intent of the vehicle.

 

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 pans, engine covers, and the engine oil cooler for leakage. Inspect for oil leakage into the engine coolant.

 

Improper Reading of the Oil Level Indicator (Dipstick)

The vehicle must be parked on a level surface to obtain accurate oil level readings. 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

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 to assure the oil has had enough time to drain back into the crankcase. 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.

 

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.

 

High Speed or High RPM Driving

Continuous driving at high speeds/high RPMs may 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 or hauling additional weight will increase oil consumption. 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.

 

PTO Operation

Operation of a PTO will increase fuel and oil usage, as the PTO driven accessory uses engine power to operate.

 

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 from Condensation

On vehicles that are usually driven short distances, less than 8 km (5 mi), especially in colder weather, 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, 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 8000 km (5000 mi) and the oil has been changed for the first time. During initial engine break-in periods before the first oil change, oil consumption may exceed 1.9 liters (2 quarts) or more per 379 liters (100 gallons) of fuel used.

 

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

Begin oil consumption test after next regularly scheduled oil and filter change. Oil changes should not be performed during the test.

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 most of 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.

Dealer should record the vehicle mileage, date and engine hours at the start of the test on the form included in this bulletin.

Ask the customer to verify and record the date, odometer, oil level, fuel added, and engine hours, each time the vehicle is fueled, following steps 3-5 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 possible. The dealer will add oil to return the oil level to full. If the oil level remains above the add mark, the customer should continue to operate the vehicle and verify the engine oil level until either the oil level drops to or below the add mark or at least 4800 km (3000 mi) has accumulated since the test began 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 379 liters (100 gallons) of fuel used, 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 379 liters (100 gallons) of fuel used, explain to the customer that their engine meets the guidelines for oil consumption.

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NEW INFORMATION YET TO BE VALIDATED:

 

I was told by a somewhat reliable source that on the 8.1L engines the valve covers had a design flaw in the internal baffling design. These baffles are there to route (splash etc) the oil back to the drain holes in the block. Apparently with the 8.1L the oil gets captured and pressurised in the cover not letting it drain back as it normally would and it ends up flowing into the exhaust valve.

 

I have not verified it yet and have heard there is a Service Document now out. This would explain why I have had oil consumption and smoking but, the plugs were looking ok.

 

Anyone in the know, have any information on the validity to this or is this really related to the manifold pipe idea noted above?

 

 

Does anyone have any further information on this idea either?

 

The fact that I have to wait 15 minutes after shutting my 8.1lt off to get an accurate oil level reading on the dipstick makes me wonder about this as an issue as well.

 

I'm putting together a plan now to get my 8.1 lt to stop using as much oil as I can get it too...and I'd appreciate any ideas any of you have to help me along.

 

Like I've said before, I love my truck....and have no intention of suing GM for the flaws...or replacing it any time soon. I just want to attempt to fix it on my own if possible.

 

Thanks,

Lance

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I use about a quart between oil changes, or 3000 miles. Interesting part is that not all 8.1's have high oil consumption, just some. I have also heard that there is a re-designed IM gasket that seals better than the original. Issue is that the bolts are not 90 deg to the flange, so the IM slides when the bolts are torqued in.

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Check out this link here about the GM limit on oil consumption for starts.

http://www.gm-trucks.com/forums/index.php?...l=8\.1+oil

 

Also the 8100 vortec engines don't have a PCV valve.

http://www.chevyavalanchefanclub.com/cafcn...ic,15701.0.html

"1) The 8.1 does not have a PVC valve. Makes me wonder how

the oil vapors are controlled. I realize the smaller V8 has one,

and its replacement helped with the issue."

 

Answer: The crankcase ventilation system has no serviceable components so routine maintenance of the system is not required. A closed crankcase ventilation system is used in order to provide a more complete scavenging of crankcase vapors. The air cleaner supplies the fresh air through a filter to the crankcase. The crankcase mixes the fresh air blow-by gases. This mixture then passes through a pipe/passage located in the intake manifold.

 

8.1L only

 

Some of the fixes for this is changing the manifold bolts as related to the ones in 2500 Avalanches.

http://www.chevyavalanchefanclub.com/cafcn....html#msg684947

http://www.gm-trucks.com/forums/index.php?...=manifold+bolts

 

Do a search here on manifold bolt and learn more about this.

 

Brian1

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If you pull the intake and look on the bottom you will see a port sticking down. This port is essentially the PCV valve. It sits right on top of the valley tray and sucks the oil that is splashed on to it. If you take a bent peice of pipe, with the opening pointing up towards the intake, and tack weld it to the port it will fix the oil consumption

 

 

By chance does anyone have a picture of the bottom of an intake manifold from an 8.1 lt they could share?

 

I want to try this procedure, but would like to know a bit more about it before diving in to my daily driver.

 

I love my truck. It's a 2002 with 106,000 miles on it now and I have no desire to replace it...but I'd sure like to have to quit worrying about topping off the oil every 1,000 miles.

 

Thanks,

Lance

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