Oil on spark plugs :(

[OR VietVet]

A valve cover gasket will not cause problems with the part of the spark plug threaded in the cylinder. The leaking gasket can be bad enough that it coats the exposed part of the plug and can also cause problems with the plug wires. List the codes that you retrieved and those need to be addressed. Step by step, basics first.

 

[wjburken]

Checked rest of the spark plugs and turns out
On a driver side plug 1, 2,3 oily. Number 4 looks ok.
On a passenger side all of them (except 8) are fine. Dry no oil sign (pic)
Valve cover gasket problem?

Just to be clear, when you say plugs #1,2,3 & 4, you are referring to the plugs on the drivers side counting front to back?

Typically plugs are numbered with #1,3,5&7 on drivers side (front to back) and #2,4,6&8 on passenger side.

 

[Tim10]

Just to be clear, when you say plugs #1,2,3 & 4, you are referring to the plugs on the drivers side counting front to back?

Yep, I just counted them from front to back on a drivers side

 

[Tim10]

A valve cover gasket will not cause problems with the part of the spark plug threaded in the cylinder. The leaking gasket can be bad enough that it coats the exposed part of the plug and can also cause problems with the plug wires. List the codes that you retrieved and those need to be addressed. Step by step, basics first.

I don't have any codes popping up or check engine light. Only when I run "smog check" on my app it shows EGR/VVT system and Evoparative system test fail...

 

[OR VietVet]

I don't see how those concerns can cause oil fouling on your plugs. When you have the plugs all out, always replace when they have the mileage and wear on them that these show. Then run for say 1k-2k miles and pull them and recheck. You never experienced a misfire feel, correct? If it did misfire it should be setting a code. Do you run premium fuel or just get the least expensive you can? Do you put in an additive?

 

[Tim10]

I don't see how those concerns can cause oil fouling on your plugs. When you have the plugs all out, always replace when they have the mileage and wear on them that these show. Then run for say 1k-2k miles and pull them and recheck. You never experienced a misfire feel, correct? If it did misfire it should be setting a code. Do you run premium fuel or just get the least expensive you can? Do you put in an additive?

I ordered spark plugs and going to pick them up today or tomorrow. I have this Tahoe for almost 2 months and never had trouble codes or misfire, the engine is running smooth and strong so far...The only additive I used was SeaFoam, poured in the gas tank when I bought it, My Tahoe was sitting in a parking lot ready to be sold for about 10 months. I fill up mostly at Costco, just regular gas.
What do you think about oil on top of the valve cover, picture that I posted before?

 

[OR VietVet]

That stain could be from seepage of oil from close to cover area and wind blows it around. Have you had it inspected, on the ground and in the air, to inspect for leaks or seepage?

 

[Tim10]

That stain could be from seepage of oil from close to cover area and wind blows it around. Have you had it inspected, on the ground and in the air, to inspect for leaks or seepage?

No, haven't had it inspected, only when changed oil, mechanic said bottom looks fine, no leaks or anything, but he didn't check this spot. I'm gonna remove the cover and inspect close this area... might find affected area

 

[OR VietVet]

Quick question. Do you have your oil changed at a full service shop or a Quick Oil Change place like Jiffy Lube or Oil Can Henry's? Different quality of mechanic/technician.

 

[Tim10]

Quick question. Do you have your oil changed at a full service shop or a Quick Oil Change place like Jiffy Lube or Oil Can Henry's? Different quality of mechanic/technician.

I'm in Canada and yes, it was a quick oil change station and I had a chance to look underneath and was pretty clean