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Discussion Starter #1
I have a 99 Sierra 4x4 NBS 5.3L V8 with 135,000mi.

This is what my spark plugs looked like after 25,000 miles, It smokes sometimes on start up, but thats all and it always goes a quart low between oil changes. Has anyone experienced the same problem? Is it valve seals, Rings or what?

thanks in advance
 

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first thing, like I was just told, get rid of the bosch. They are apparently crap plugs (they have the smallest exposed electrode, and after time, the electrode will recess into the porcelain, and make the plug work even worse.

That said, holy shit, nice plugs.

I don't know specifically what did that. I know that when I went to autobarn to buy my nwe plugs, they had a series of pictures of used spark plugs, in various states (detonation, lean, etc...), and I saw your plugs, but can't remember what cuased it.

good luck.
 

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Discussion Starter #8
I found i can get valve stem seals for $18 for a local engine shop, does anyone know how hard or whats involved in replacing those? I know about having to compress the cylinder with air to hold the valves up but other than that i have no idea.
thanks
 

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^^Isn't that the pic from the back of the Haynes manuals. :lol:
You know it. I think we've all seen it a bazillion times!
 

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I found i can get valve stem seals for $18 for a local engine shop, does anyone know how hard or whats involved in replacing those? I know about having to compress the cylinder with air to hold the valves up but other than that i have no idea.
thanks
Remove all sparkplugs and TDC for the first cylinder. Put an air fitting in the spark plug hole and pressurize the cylinder. You need to compress the valve spring and remove the retainer but before removing the retainer, press down on the valve to make sure the air pressure is holding it up. After removing the retainer, remove the spring(s), then the old seal. Put on new seal and reverse the process. Repeat for each cylinder, making sure the piston is TDC. The reason for this is if you have a 'whoops' you don't lose the valve and have to pull off the head.

When done, make sure you use the right valve cover sealant and that both valve cover and head are clean of old sealant.

Have fun! :D
 

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Discussion Starter #12
Well i just got done changing the valve stem seals(whata bitch) anyway hopefully that will fix my oil consumption problem. Thanks for all the help and i do not recommend doing this if you don't have alot of time and inclination!!:crazy:
 

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hey man, i've worked at a parts store (NAPA to be exact) for 4 years now, and I also mechanic on the side, that being said, definately get rid of the bosch spark plugs, i've seen this happen over and over........... you have to put the ac-delco plugs back in the truck that it came with...... they are actually what they call a 100,000 mile plug! in these new vehicles, gm's in particular, if you put an "aftermarket" plug in there it will run good for a few thousand miles, and then run like complete shit! even though the ac-delco's are about twice the price of some other brand....... you need to use them... that being said, good luck to ya, and i'm glad to hear the seal replacement went alright for ya!
 

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hey man, i've worked at a parts store (NAPA to be exact) for 4 years now, and I also mechanic on the side, that being said, definately get rid of the bosch spark plugs, i've seen this happen over and over........... you have to put the ac-delco plugs back in the truck that it came with...... they are actually what they call a 100,000 mile plug! in these new vehicles, gm's in particular, if you put an "aftermarket" plug in there it will run good for a few thousand miles, and then run like complete shit! even though the ac-delco's are about twice the price of some other brand....... you need to use them... that being said, good luck to ya, and i'm glad to hear the seal replacement went alright for ya!
NGKs are also speced for many GMs. the TR55 plugs are proven to work well in the LSx motors.
 

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Well i just got done changing the valve stem seals(whata bitch) anyway hopefully that will fix my oil consumption problem. Thanks for all the help and i do not recommend doing this if you don't have alot of time and inclination!!:crazy:
Yeah, it is time consuming and a pain if you don't have the right tools. When I used to work on engines, I made a spring compressor that hooked under the rocker stud nut. Made the job easier..... as long as the stud didn't pop out.
 

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True. They are even recommended to be used in some of the trucks.
Put NGK Iridiums in my 02 6.0 in the 2500 with MSD wires. Ran a lot better after I pulled out the 75k mile AC Delco, but new plugs and wires prolly woulda done that, not just big name stuff. I was gonna say before everyone posted the pic that your plugs look like you're burning oil...not too much cus the deposits aren't wet, but enough to mess things up.

Hope you got it fixed.
 
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