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Oil in spark plugs

M

motoreese

Member
Messages
10
Location
Yuba City
I am new at working on Hummers, mine is a 2006 H3 i5. Yesterday is was shuddering at idle and after some research I decided to do a tune up and clean the mass air flow intake. Changed the air filter to a K&N, cleaned air sensor near the air box, took off the air intake and cleaned the mass air flow intake. I also changed the spark plugs and put new coil covers on. While changing out the plugs there was oil on top of the plugs. When I took the plugs out the threads were covered in oil. I am thinking the valve cover gasket needs to be changed but I wanted to know what everyone thinks. Thanks for any help.
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deserth3

deserth3

Well-Known Member
Messages
1,069
Location
Conroe, TX
What does the other side of the throttle body look like?
These trucks are known to suck up oil through that crack case ventilation tube. If there is oil coming out of the tube into the intake simplest fix is to add a pcv valve.
There are baffels in the valve cover that is supposed to prevent this. But they don't always work well.

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M

motoreese

Member
Messages
10
Location
Yuba City
deserth3 said:
What does the other side of the throttle body look like?
These trucks are known to suck up oil through that crack case ventilation tube. If there is oil coming out of the tube into the intake simplest fix is to add a pcv valve.
There are baffels in the valve cover that is supposed to prevent this. But they don't always work well.

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Click to expand...

Didn't get a picture of the other side. It was not as dirty. Maybe 25% of this side.



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M

motoreese

Member
Messages
10
Location
Yuba City
deserth3 said:
Check your pcv tubing.

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Click to expand...

94a87072b9f399b3fd9f22053b0e5b53.jpg


I checked the tubing under this air box. There was no oil build up, tube was secure, not cracked or brittle.

There is no oil dripping onto engine and I have not gotten any oil burning smell.



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M

motoreese

Member
Messages
10
Location
Yuba City
Also, when I had everything off, there was no oil inside cool air tubing coming from air filter box, or inside the box labeled "vortex".
The oil inside the spark plug well looked clean and didn't smell burned either.


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deserth3

deserth3

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Messages
1,069
Location
Conroe, TX
Ok... Last time.... Replace pcv hose. Add of valve. Recheck in one month. Good luck

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Kick'n Dust

Kick'n Dust

Well-Known Member
Messages
62
Location
Dearborn Heights
Don't worry about pcv unless you have oil consumption problems. You just need a camshaft cover gasket. I'm a certified GM tech who drives a H3, you can trust me lol

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deserth3

deserth3

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Messages
1,069
Location
Conroe, TX
I'm not a mechanic. But I disagree about which need to be taken care of first.
The pcv valve is the easier, quicker, cheaper fix. And with a little luck the oil leaks may stop or slow down.

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J

JPaul

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Way up north, UT
If it's developing excessive pressure in the crankcase, it could cause oil to leak from the valve cover gasket, so thinking of the PCV system first is not a bad line of reasoning. However, the 3.5/3.7's don't actually have a PCV valve, not one that you can replace anyway. The hose going from the cover to the intake resonator box (before the throttle body) is just an open hole, there is no valve. I believe the other hose that goes from the cover to the throttle body does have a PCV on it, except it's built into the valve cover and is not serviceable other than taking off the valve cover and cleaning it out, or replacing the entire cover if it's really buggered up. If that is getting gummed up badly though you likely have other, more serious issues.

Most likely is the valve cover gasket needs to be replaced. In either case, you're going to have to pull of the entire intake and valve cover to do either service, so you might as well do them both, clean out the valve cover and its vents, as well as replace the gasket. You could theoretically spray carb cleaner down the second nipple to try and clear it out to see if that is the problem, but then you're going to need to change your oil as well since it's now contaminated.
 
deserth3

deserth3

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Messages
1,069
Location
Conroe, TX
There's oil in the intake so most likely the pc orifice is clear.
I'd just add an online pcv valve somewhere along the hose.

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M

motoreese

Member
Messages
10
Location
Yuba City
JPaul said:
If it's developing excessive pressure in the crankcase, it could cause oil to leak from the valve cover gasket, so thinking of the PCV system first is not a bad line of reasoning. However, the 3.5/3.7's don't actually have a PCV valve, not one that you can replace anyway. The hose going from the cover to the intake resonator box (before the throttle body) is just an open hole, there is no valve. I believe the other hose that goes from the cover to the throttle body does have a PCV on it, except it's built into the valve cover and is not serviceable other than taking off the valve cover and cleaning it out, or replacing the entire cover if it's really buggered up. If that is getting gummed up badly though you likely have other, more serious issues.

Most likely is the valve cover gasket needs to be replaced. In either case, you're going to have to pull of the entire intake and valve cover to do either service, so you might as well do them both, clean out the valve cover and its vents, as well as replace the gasket. You could theoretically spray carb cleaner down the second nipple to try and clear it out to see if that is the problem, but then you're going to need to change your oil as well since it's now contaminated.
Click to expand...

I have seen were people people have cleared the build in PCB valve with carb cleaner then changed oil. I plan on doing both so I also have new gaskets, is there any good videos on how to do this job. There is a couple of bolts on the driver's side of the cover that are going to be a pain to get too.


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Kick'n Dust

Kick'n Dust

Well-Known Member
Messages
62
Location
Dearborn Heights
So if you really want to know if you have a problem with the pcv system just attach a vacuum gauge to your dip stick tube. It should only read about 1-2" vacuum. If the pcv is stuck open it will be higher, and if it is stuck closed you could see positive pressure.

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