Oil Consumption

[Bud]

Here we go again.

I have a 8.1 that I think uses a little to much oil. I read

on the forum about changing the intake bolts. The dealer

will not do this with out a bunch of testing. Can I do this myself?

What is the part number of the bolts? What is the torque of these bolts?

Has anyone done this own their own, tell me about it!!

[chasmotech]

Bud,

This is from one of my comments found currently on page 2 in this section titled

"Where are the 8.1's" you might wan't read up on all threads.:

 

I had the 2001 8.1/Allison combo. I just traded for a new 2004 Duramax/Allison.

I put 50k on the 8.1 and the only problem was oil consuption.

Went back to the dealer several times for a resolution.

First time it spent 16 days at the dealer. (mechanic broke an intake bolt while torqueing down and had to order a new head.)

Still used about 1-1.5 quarts per 800-1000 miles.

Second time in retorqued head and intake bolts, replaced intake gasket.

Still burning same amount of oil.

Lots of luck if you get one..

[silverado3500]

There was another thread somewhere in here about changing you oil weight/viscosity, helping reduce the oil consumption....I'm still looking for it...

[Bud]

I've always been told that changing oil weight

was a no, no!!

[JayMan]

I've always been told that changing oil weight

was a no, no!!

Sez who? The stealer? Those nutjobs at GreenPeace?

 

North American market cars almost always specify the lightest oil possible to meet CAFE (Corporate AVERAGE Fuel Economy, my emphasis on "average"), such as 5W-30. Ford's and Honda's are starting to specify a 5W-20.

 

This produces miniscule improvements in fuel economy. Say if you're already getting 40 MPG, you might increase 0.2 MPG. If you're getting 15 MPG, you might increase 0.01 MPG. If you look up the API/SAE definitions of "energy conserving" you will find the light viscosity only has to provide a 1-2% gain.

 

CAFE has nothing to do with the public, it helps the car maker. That miniscule 0.2 MPG or whatever is applied over hundreds of thousands of units, which is then turned into a "credit" that the maker can apply to vehicles with poor fuel economy to offset the potential of fines.

 

Nobody tells you what effect this has on your motor. CAFE really is a crock of s***.

 

Most European makers (VW/Porsche/Audi, Mercedes Benz, etc) specify heavier viscosities like 5W-40, 0W-40, 15W-40, 15W-50, etc etc.

 

Oh, the Honda that here in North America needs a 5W-20? Same motor in the UK runs a 5W-40.

 

I bought new a 1990 Toyota 4Runner. It had a vague general recommendation of a 10W-30, though the shop manual had many recommendations. I ran Mobil Delvac 1 5W-40 except the 4 years I lived in Utah when I ran Mobil 1 15W-50.

 

The 4Runner used 1 quart every 8,900 miles on Delvac 1 5W-40. Running Mobil 1 15W-50 in hard mountain and desert driving, and high speeds on I-15, 1 quart every 10,100 miles. Supposedly, that Toyota 3.0 V6 has tight clearances. What does that tell you??

 

Even more interesting: the GM production vehicles seem to recommend a 5W-30 year round. The same exact motor, built in the same engine plant and run down the same line, is also available as a "crate" motor from GMPP (General Motors Performance Parts).

 

GMPP recommends the use of a 10W-40 in all their "crate" motors including the LS1's. What does that tell you? It's the SAME motor as you have under the hood.

 

I don't have an 8.1, but here is my oil consumption report, which I think is somewhat poor compared to other vehicles I used to have:

 

Mobil 1 0W-30: 1 quart every 4,200 miles

Mobil 1 10W-30: 1 quart every 6,800 miles.

 

I have to run the 0W-30 in winter due to my extreme cold temps here. My question is, why is my oil consumption quite a bit more running the 0W-30?? All my heavy towing is in summer runing the 10W-30, so you'd think I'd use MORE oil in summer due to the heavier loads.

 

Once it warms up in April, I'm going to try Mobil Delvac 1 5W-40. I've used Delvac 1 in all my personal cars/trucks in the past with excellent results.

 

Is it cold where you live? If not, at least temps of 40 F or higher, try a short oil change interval with 10W-40 and see if that makes any difference. Some folks with LS1's who rally and really romp on them, run Mobil 1 15W-50 with very good results.

 

I've heard of the oil consumption issue from LS1 owners and even from other small block Vortec owners (4.8, 5.3, 6.0). In almost every case, using a heavier oil has substantially reduced their oil consumption problems.

 

At the rate you're going, those O2 sensors and the catalytic convertors won't last long. What have you got to lose? Just don't tell the stealer if it's under warranty.

 

Then again, the stealer will try to tell you that 1 quart every 1,000 miles or so is "normal."

[midnight8100]

Here we go again.

I have a 8.1 that I think uses a little to much oil. I read

on the forum about changing the intake bolts. The dealer

will not do this with out a bunch of testing. Can I do this myself?

What is the part number of the bolts? What is the torque of these bolts?

Has anyone done this own their own, tell me about it!!

I just got my intake bolts changed in my 8.1 under warranty.

I showed them the nasty old carbon caked spark plugs -- no dispute could be made. I also has the TSB # handy its Bulletin No.: 02-06-01-035

I havn't driven enough miles yet to tell if its any better, but as most report this is a temporary fix at best. I have read something about new intake gaskets for '03 or '04 on the 8.1 but am not sure about it. I'm sure it will be years before any aftermarket companies make gaskets for these engines. Adding some oil every once in a while doesn't bother me (mine only uses a quart every 2K maybe, going to 10W30 Mobil one seemed to help) but what I don't like is the idea of the valves and combustion chambers being gunked up like those plugs I removed with only 30K on them (I wouldn't run 100K on one set anyways)

 

The intake manifold bolts are GM part number 12561518 there are 10 of them, not sure if that part number includes 1 bolt or 10? Labor in a truck it lists as .7 hours. You should be able to get it done under warranty though or find a new dealership!

 

***Also be sure to check under truck real well for leaks before you go off warranty, I had to have the oil pan gasket replaced, as well as the rear driveshaft seal on xfer case and one front outer axle seal and the P/S pump seals (shaft and housing)***

 

Hope this helps ---- Ted

 

 

Below is a copy on the TSB:

 

 

Engine - High Oil Consumption

 

File In Section: 06 - Engine/Propulsion System

 

Bulletin No.: 02-06-01-035

 

Date: October, 2002

 

TECHNICAL

 

Subject:

High Oil Consumption

(Replace Intake Manifold Bolts)

 

Models:

2002 Chevrolet Avalanche

2001-2002 Chevrolet Silverado, Express, Suburban

2001-2002 GMC Sierra, Savana, Yukon XL

2001-2002 Chevrolet and GMC C6-7 Conventional Cab Medium Duty and

B7 School Bus Models

with 8.1L Engine (VINs G, E - RPO L18)

 

Condition

 

Some customers may comment about higher than expected oil consumption. Because this type of engine is used under various load conditions, the dealer should verify that the vehicle is using more than 0.946L (1 quart) of oil for every 379L (100 gallons) of fuel used.

 

Cause

 

Oil vapor pulled into combustion chamber through the intake manifold may cause this condition.

 

Correction

 

Replace all the intake manifold bolts. Replace one bolt at a time in sequence to keep the intake manifold from shifting.

 

Notice: Ensure the intake manifold does not shift as the intake manifold bolts are tightened in the proper sequence. Failure to follow the entire intake manifold bolt tightening sequence exactly may result in an oil leak and serious engine damage.

 

1. In the order shown, remove each bolt and replace with a new bolt. Insert the new bolt and tighten to 5 N.m (44 lb in). Then move to the next bolt in sequence until all bolts have been replaced.

 

2. After all of the bolts have been replaced, tighten each bolt in sequence to 8 N.m (71 lb in).

 

3. Tighten all bolts in sequence to a final torque of 12 N.m (106 lb in).

 

Parts Information

 

Parts are currently available from GMSPO