Any GM techs out here?

[fudgie]

I got a 04 GMC Sierra Z-71, 5.3L, 76,000 miles. Mostly drive it in the winter and to my 2nd job during the summer. Had it since 06. Its babied mostly but does get a occasional work out in the fields pulling fence posts or driving up and down the plowed field. But not alot of pulling. She has been using oil this year. Twice the 'check engine oil' thing came on. It was a quart or 2 low. It doesnt mark the floor or burn it. Where does it go? Still runs great. I use a name brand oil also.

[R J]

Send a PM to Mad6gun, Mark Doenges, he is a GM drive ability tech.

[fstsix]

Just poked around a little, looks like your not alone,, look at the last post there is a other link also for consumers to get info..good luck.http://www.chevytalk.org/fusionbb/showtopic.php?tid/220918/

[Skinhead]

Fudgie,

Hard to say whats going on with out looking at it, but here are some thoughts.

Check and make sure it's not going into the water jacket (bad Head gasket) your coolant reservoir would be over full.

It could be the PCV valve stuck open and allowing oil to be sucked into the intake manifold.

You didn't mention if it was smoking (blue exhaust), if it is, could be PCV, cracked ring, or valve seals.  How many miles/quart?

I have a 03 tahoe that uses about a quart every 1500 mi.  I believe it is sucking it through the PCV system.


I'd be interested in Mad6gun's thoughts as well.

[Marcel]

Try a Different brand of oil.

Sometimes motors react funny to different oil.If you are running synthetic , then quit that.

I have had similar problems with the weird man made stuff.

Dino oil is better for it.

Also a gasket that gets overlooked on these is the intake gaskets but usually that means it

will be getting rid of your coolant in short and quick fashion.

Oil or gaskets is probably the culprit.

[fudgie]

No it doesnt burn it.

Coolant is fine, with water pump replaced last march.

I did try synthetic but it seemed like it needed changed faster then with dino.

I usually use penzoil but use what ever is on sale with filter. I think I only changed the oil twice this year. Soon to be 3rd.

Light came on this summer and yesterday.

[vanagon40]

Hey,

I'm no GM expert, only an old somewhat farm mechanic.  The oil has to be going somewhere, so if it is not leaking, you must be burning it.  How many miles before it is a quart or two low?  Most of my vehicles have around 200,000 miles and use oil, but it does not really show in the exhaust or tailpipe.  Sometimes my old Lebaron convertible will smoke in the summer after sitting at a light, but not usually.

I think that any vehicle that uses no more than 1 quart of oil per 1000 miles will not show any signs of oil consumption (other than at the dipstick).  In the 60's and early 70's, we used to think this was normal (and good for any vehicle with over 50,000 miles).  I have had vehicles that both leaked and burned oil at the rate of 1 quart per 100 or 200 miles, but they were sloppy dirty and oily.  I also used to continually increase the oil viscosity until I hit straight 50 weight (to keep up the pressure and reduce consumption), at which point I figured I needed to either sell or scrap.  I realize that increasing the viscosity is a double edged sword in that it temporarily helps, but also exacerbates the problem. 

Again, it would help if you could quantify the miles you drive before being down a quart or so.

[the inspector]

fudgie....if it's not leaking, no intermix  anywhere, then it has to be burning it. Most newer vehicles that are running a converter in the exhaust system will mask the smoke we old timers are use of seeing (blue smoke) no blue smoke converter cleaning up the exhaust out the tailpipe.....but still burning oil...a little at a time over the week. Can't see it but it's doing it. Remember, no leaks, no intermix, oil level going down, ya burning it for sure. Really not a big deal just keep an eye on the level.

"the inspector"

[fudgie]

Jeez, not sure maybe 2-3k miles before it was low. I think i changed it this summer. it has a computer that counts down the % till it needs changed. I think i only put 8,000 miles on it this year, if that. I think it read 'low' near the time it needs changed.

[Hoser]

I wouldn't worry about that amount, just check it once in a while.  You're just used to the Valkyrie, that never needs oil!     hoser

[Marcel]

Just remembered a line I heard from a GM Mechanic.

These particular trucks came with ,,get this Ceramic coated Pistons.

This would have a hit and miss effect.

Sometimes the motors would breakin and last a long time.

I am afraid my friend you have one that did not seat in and run as intended.

Ceramics is your prob.

Now you have many remedies that might help.

All involve you either fixing the problem or trading the sucker.

On the bright side these trucks with 4 wheel drive are good trade ins.

Check with a few people and look on the NHTSA recall list to see if these have been recalled.

Just go to the sight and type in your vehicle and this will let you know if Government Motors is

on the hook for a free fix.

Ceramic Coated Pistons is definitely your problem though.

Big AL

[Jabba]

Check your oil every other fill up and you'll be cool.  My wife has an 04 Subdivision, uh, er Suburban, and it uses about a quart over a 7,000 mile oil change period.  It's got the 5.3 in it too.

Jabba

[Skinhead]

Just remembered a line I heard from a GM Mechanic.

These particular trucks came with ,,get this Ceramic coated Pistons.

This would have a hit and miss effect.

Sometimes the motors would breakin and last a long time.

I am afraid my friend you have one that did not seat in and run as intended.

Ceramics is your prob.

Now you have many remedies that might help.

All involve you either fixing the problem or trading the sucker.

On the bright side these trucks with 4 wheel drive are good trade ins.

Check with a few people and look on the NHTSA recall list to see if these have been recalled.

Just go to the sight and type in your vehicle and this will let you know if Government Motors is

on the hook for a free fix.

Ceramic Coated Pistons is definitely your problem though.

Big AL

I believe the pistons may be Teflon coated if anything, not ceramic.  The gen4 small blocks have a history of piston slap on cold start, which is the ticking sound that goes away as the piston heats up and expands.  It is not a problem, only a annoyance.  Not all do it.  I've seen trucks we bought back from fleets with piston slap and 300K on them, no problem.

If you are getting 3000 mi/qt, you don't have a problem.

[Dogg]

fudgie....if it's not leaking, no intermix  anywhere, then it has to be burning it. Most newer vehicles that are running a converter in the exhaust system will mask the smoke we old timers are use of seeing (blue smoke) no blue smoke converter cleaning up the exhaust out the tailpipe.....but still burning oil...a little at a time over the week. Can't see it but it's doing it. Remember, no leaks, no intermix, oil level going down, ya burning it for sure. Really not a big deal just keep an eye on the level.

"the inspector"

just an fyi fudgie.  burning oil, regardless of how much will eventually clog the cat. there is SOME oil being burned but, not in 1500 miles and buning a qt. see, oil changes are reccomended every 3000 or 3 months for a reason. dont care what manufacturer says...oil will break down over time and thus be no good. 3 months of sitting with very little use will cause it to break down and not be as efficient as new oil. 
  Just because your oil life meter tells you its still good, doesnt mean a thing. its see by a mileage timer that only logs miles till oil is no good. if the truck sits more than it is used, it will breakdown just as if you had it in there say 6000 miles.

 Everyone has their own way of doing things but, I will tell you, that 5.3 is kind of a problem engine unless you do  exact regular maint on it. every 3 k or 3000 miles you change the oil. If using syn and had more problems, its because you HAVE A PROBLEM. not because the enigne doesnt like it... my ranger, 02 130k on the ticker started smoking a bit from mileage. I expected it. I run mobil1 syn ib her. I also add a can of restore every 4 oil changes. she doesnt burn any oil anyore. runs like a top and I change the oil every 3000 miles anyway.
 Not a big fan of additives but, restore fixed my issues and I will be able to run her for a very long time now.

  whole thing is, if you are burning 1 qt every 1500 miles, you have a chance to clog the converter and then its big money to fix...need to have it looked at seriously.

  tho, mark is the GM guru so, what he says is more important than any of us. Im a master tech but, work on anything. I have no brand specialty.

[3fan4life]

Try a Different brand of oil.

Sometimes motors react funny to different oil.If you are running synthetic , then quit that.

I have had similar problems with the weird man made stuff.

Dino oil is better for it.

Also a gasket that gets overlooked on these is the intake gaskets but usually that means it

will be getting rid of your coolant in short and quick fashion.

Oil or gaskets is probably the culprit.

Now you've gone and started a "fight" about oil.

I've used synthetic oil in everything that I own since 1994 and would "never" consider going back to using "rotten" dinosaurs in any of my engines.

Fudgie,

Are you sure that there aren't any leaks?

I have an 04 GMC with 76k mi and it doesn't use any oil whatsoever.

[The Breeze]

The GM recommended oil grade for this engine is => 5W-30 SAE Engine Oil or 5W-30 Dexos1 Engine Oil which is the newest specification due to our "Global" usage of vehicles.   

Oil Consumption Diagnosis  

Excessive oil consumption, not due to leaks, is the use of 1 L (1 qt) or more of engine oil within 3,200 kilometers (2,000 miles).

This usage amount can also increase as the engine mileage increases along with extended idle time.

A PCV fresh air hose that is pinched or restricted by plastic casting flash (this would normally be a concern since new, or shortly after engine repairs).

   •  Plugged PCV baffle drain holes in the valve cover that has the PCV vacuum pipe attached to it
      (this would normally be a concern at high mileage).

   •  An improperly sealed PCV valve cover baffle (this would normally be a concern since new, or
      shortly after valve cover replacement).

   •  Over-aggressive valve lifters (generally occurs at low mileage - less than 10,000 miles or so).

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.

[Marcel]

Ok The GM folks call the polymer coating on the piston a Grafal Coating.

I concede that the mechanic I talked to was wrong about ceramic coating.

I also concede the oil you use makes no difference.

It is in the design of the heads and the seals they are using  on the valve stems.

That's why you would not notice the oil being used as the catalytic converter would mask that.


In the end it was determined that the valve seals were at fault and because of their design and because of the materials used in the valve guides that the valves wore the guides and the valve seals did not seal and when the intake valve opened - a rush of air out of the crankcase entered into the fuel stream with the air from the intake manifold and the end result was that it would funnel a quart of oil every 500 miles - or one quart of oil every 3 days.

Trade or do a valve job on it to elimainate the problem altogether or trade the beast.

Sooner or later this oil usage will stop up the converter.

But down here it would not matter we would just strangely lose the converter on a stump some-


where.Spent about an hour looking for this answer and i believe we have nailed it down.

you could also run a little Lucas , about 32  ozs' per oil change and slow this down substantially.

That is a plausible alternative.

Lucas seems to make old engines and the sealing surfaces more efficiant.

Just a thought.

All of my v-8 engines use a little oil, about a half a quart per 2000 miles and thats all.

One of mine has 190,000 on it and still runs as good as it did when new.

Oil is cheap and new cars expensive, so your choice of course.

[the inspector]

I somewhat agree with Marcel on most items. I don't see the converter plugging up with the slight amount of oil being burned (converter does run very hot) and a slight amount of oil will be evaporized. Now IF you are pouring a large amount of oil through it it MIGHT get plugged up in which case you lose it on the stump (as per discussed) you can change the valve seals to slow down the amount oil leakage into the cyl's, not to bad of a job, as far as valve guides go (remove heads and send to machine shop) $$$$$ and much work.

Or just check oil level and keep full.

"the inspector"

[fudgie]

Hmmm....Now what? Tossed around trading it but what they will give me and what I owe is not far apart, unless I sold it out right. Paid to much for it a few years ago. It was a 'got a divorce, credit is crap, need a truck' purchase. Afraid it I sell it and get something else as I will be getting someone elses junk.

Dogg maybe onto something. It seems to be low on oil when its gets near its 20% oil life. It a daily driver but may set all weekend when on the valk. I was trying to remember how much I had to add this year. Maybe 12-14k in miles and 2 -3 qrt. Never really did use any the last few years tho. Maybe I cant read a dip stick! 

[the inspector]

fudgie this is not really a big problem. Ride the Valk as much as you can, not that you don't brother. New oil will help I agree with Dogg on that one. Oil is much cheaper then any other option. But do not fret, it's not that bad. Drive it easy, change the oil and don't worry about it, it will run like that forever (as long as you keep it full of oil) and if it burns a slight amount it's OK really.

"the inspector"

[fudgie]

fudgie this is not really a big problem. Ride the Valk as much as you can, not that you don't brother. New oil will help I agree with Dogg on that one. Oil is much cheaper then any other option. But do not fret, it's not that bad. Drive it easy, change the oil and don't worry about it, it will run like that forever (as long as you keep it full of oil) and if it burns a slight amount it's OK really.

"the inspector"

lol will do!  It usually only get 30 miles from home max. Maybe 100 miles to indy once a year. Rest is on the Valk or rent a car if its to far cause nothing parties like a rental!

[the inspector]

Boy you said it brother.....as long as the Valk is cooking and you and kit are good....everything is GOOD. Have a Merry Christmas Brother!

"the inspector"

[Dogg]

keep that truck forever. nothing wrong with it. just keep an eye on the oil, time increments between changes(as well as mileage) and you got a nice truck to run til retirement...

[solo1]

Brian, back when I was a kid with no money I had a worn out, rusted out '36 Chevy POS, all that I could afford.

It used three quarts of oil going to Bluffton and back (about 40 miles). I used other people's crankcase drainings. That old Chevy never lat me down, even started in -15 degree weather, not enough compression to slow the starter. 

Drive it and don't worry about it.