I pulled my plugs and the drivers side ones were oil and carbon covered, pure black in color. From my searches, valve seals and worn rings were the common cause for oil. How can I determine what is bad? The car has only 75K. At least one of the cylinders has a miss because of it. Thanks

 

Does your car smoke a little after you let it sit for a few hours then start it up again? It is most likely your valve seals which are VERY common on a chevy. Your plugs being black could be you running too rich. Any black smoke out the exhaust?

 

do a compression test, i'm not sure what a good number is but all the cylinders should be relatively close each other. then squirt a little oil into each cylinder and run a compression test again, if the rings are bad the oil should seal them a bit and your compression should read higher, if it doesnt then your rings are ok and valve seals are to blame.

 

My car doesn't smoke at all. In another post, Vader said you can 'cheat' by running a hotter plug. What plug would help?

 

That depends on what plug you're running now. If you go to the auto parts store you can normally show them what you've got and they can pick out a hotter plug.

 

I had 2 plugs on the right head of my truck constantly fouling up. I was changing them every 6 months. I tryed a hotter plug and kept burning the tips off. Oil consumption was a liter or 2 between oil changes.

I finally pulled the valve cover to change the valve seals to discover all 8 on that head were shot. After changing those 8 I now use no oil between oil changes and haven't changed plugs in over a year now.

For some reason the other head is fine.

Go with the valve seals first. They're easier to change than stripping the engine down for a ring job. If the plugs still foul up after that then consider a tear down.

 

How old were the plugs? What can happen is the plug can carbon up and foul. Then the cylinder can get 'washed' from all the unburnt fuel. This can cause oil to slip past the rings and gas to get into the oil. If you haven't changed the oil yet, give it a smell and see if it smells like fuel.

 

I have Bosch platninum plugs with the stock heat range and gap. These plugs were installed 4k miles ago. Should I get new plugs of the same heat range to see if it remedys the problem or will the carbon and oil foul them right away?

 

don't bother with new plugs, they'll just foul again. those plugs should go 30k miles at least on a good running engine. was the coating on the plugs shiny black or flat black? if it's shiny that's oil, if it's flat then that's carbon caused by unburned fuel. if it's oil on them i'd do the seals, if it's carbon then you probably have engine problems elsewhere. you can try a hotter plug if it's carbon fouling but that's not the right way to fix it. you shouldnt need to use a hotter/colder plug on a stock engine.

 

HEY about that letting your car sit for a few hours then starting it up again and it smokes a little mines does that and what does it mean the car runs great just i notice that smoke after it sits

 

neo,

that's probably your valve seals that need replacing. oh and try to use punctuation in your posts, makes it much easier to read them.

 

This may or may not have to do with the oily plugs, but it looks like oil is coming out from the exhuast manifold gaskets. I can smell hot oil under the hood and my exhaust smells like raw fuel. Maybe this will help pinpoint my problem. Also, I said earlier all the cylinders on the drivers side were oily but the ones I checked were, I pulled #5 today and it looked like it had normal combustion and no oil. I should get around to a compression check tomorrow.

 

check your valve covers and intake for leaks. The gas you smell is probably you running VERY rich which is probably why your plugs are all black in the first place...

 

PP,

If your plugs are all black, oil fouled, and sooty, I can't imagine the O² sensor is very clean either, since it is in the driver's side exhaust tube. That could explain a rich condition.

 

In my EGR post, I mentioned my o2 voltage dropping to .0v when I gave it gas so I knew the computer was trying to compensate with more fuel. I read in a LT1 forum that misfire may falsely indicate a lean condition to the o2 sensor so that may have been why the voltage was dropping so low. I now have a code 13 so I think my o2 is shot. It is raining here and I do my work outside so I prob won't get you any compression numbers.