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2002 chevy trailblazer_lt
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Discussion Starter · #1 ·
So i was cleaning my throttlebody on my trailblazer today and I said since I already have the intake off I may aswel check the plugs, so I pulled the #3 plug and it was soaked in oil

So then I checked my oil level and im down 2 quarts in 3600 miles again leading me to believe I've got bad blowby but there is no smoke coming out of the tailpipe and the motor runs fine and strong

My friend told me I need new rings if im getting blowby that bad, I checked my VIN and even though I have a 2002 mine was manufactured after the date that the motors had bad rings in so I should be fine there, also I have 85K on the motor with no problems so far

It dosnt drive funny at all it runs strong, what do you guys suggest? Just keep an eye on the oil level and live with it?
 

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2005 chevy trailblazer_ls_ext
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You may not necessarily have blow by. You could have a bad valve cover gasket which allows the oil to leak down into the plug area. Other people have mentioned this in other threads.

Check the condition of the inside of your tailpipe.
 

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2002 chevy trailblazer_lt
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Discussion Starter · #3 ·
You may not necessarily have blow by. You could have a bad valve cover gasket which allows the oil to leak down into the plug area. Other people have mentioned this in other threads.

Check the condition of the inside of your tailpipe.
The oil is on the plug itself but it is also on the threads of the plug not just the tip area
 

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2003 chevy trailblazer_ls
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Do you know how to do a compression test to diag. rings and or valve leaks?
 

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2003 chevy trailblazer_ls
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Yes I know how to do a compression test, talk about a PITA
Two people, 10 minutes. One person and a remote starter switch, 10 minutes. You need to pull the fuel pump relay if there are two people doing this. That will tell you if the rings are bad.

Hey ROADIE, if you spin the engine with the key and the fuel pump relay is removed, do you know how long the starter will spin before the PCM says no more?
 

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2002 gmc envoy_slt
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The 2002 model year didn't have bad rings, they had faulting cylinder sleeves. Usually the #1 sleeve would slip down the block, resulting the piston sliding over the upper edge into the bore and making a racket or the lower end hitting the bottom edge and causing catastrophic engine failure. - All depends on how far down the sleeve slipped and how cracked it was. In my case it just made sort of a light knock or collapsed lifter sound all the time. For others it would drop all at once and BOOM no more engine, you're on the side of the road waiting or a tow.

The valve cover gaskets are known to be very leaking around the plugs and that oil can seep down onto the threads. If you were actually pushing that much oil up into the cylinders, you'd be smoking like a 20 year old school bus on a cold morning. Valve seals could be another possibility with an over-head cam engine. If you sit idling for 2-3 minutes and then rev the motor, could you be producing a momentary puff of smoke and then be clear? (Just a shot, had a 3.0 Mitsu motor in a Chrysler years ago that did that).

How many miles on her and do you know the maintenance history?
 

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2002 chevy trailblazer_lt
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Discussion Starter · #8 ·
The 2002 model year didn't have bad rings, they had faulting cylinder sleeves. Usually the #1 sleeve would slip down the block, resulting the piston sliding over the upper edge into the bore and making a racket or the lower end hitting the bottom edge and causing catastrophic engine failure. - All depends on how far down the sleeve slipped and how cracked it was. In my case it just made sort of a light knock or collapsed lifter sound all the time. For others it would drop all at once and BOOM no more engine, you're on the side of the road waiting or a tow.

The valve cover gaskets are known to be very leaking around the plugs and that oil can seep down onto the threads. If you were actually pushing that much oil up into the cylinders, you'd be smoking like a 20 year old school bus on a cold morning. Valve seals could be another possibility with an over-head cam engine. If you sit idling for 2-3 minutes and then rev the motor, could you be producing a momentary puff of smoke and then be clear? (Just a shot, had a 3.0 Mitsu motor in a Chrysler years ago that did that).

How many miles on her and do you know the maintenance history?
the truck has 83k miles on it, had no big problems whatsoever so far

I thought it was odd also that it would be the rings because it dosnt smoke at all, if I do the idle for 2 to 3min and rev it trick it dosnt blow smoke either

Seems like everyones coming to the consensus that its probobly the valve cover gaskets?
 

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2003 gmc envoy_slt
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The oil is on the plug itself but it is also on the threads of the plug not just the tip area
This is indicative of a bad valve cover gasket. The oil fills the spark plug well. As you remove the plug, the oil drains down covering the threads with oil.:m2:
 

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This is indicative of a bad valve cover gasket. The oil fills the spark plug well. As you remove the plug, the oil drains down covering the threads with oil.:m2:
He also said that the plug was coated in oil. I thought he meant the electrode was also covered in oil.
 

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I just replaced my plugs and the one in the very back had oil on the threads but not around the electrode. I didnt think much about it though because it wasnt much and it was only on the threads.
 

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I just replaced my plugs and the one in the very back had oil on the threads but not around the electrode. I didnt think much about it though because it wasnt much and it was only on the threads.
Sorry for the silly question, but if it is only on the threads and not the electrode, what does that mean?
 

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2003 gmc envoy_slt
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The valve cover can let oil leak into the spark plug well. When you remove the plug the oil drips down the threads of the plug. So what it means is that your valve cover is leaking. It is usually not a problem.
 

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2003 chevy trailblazer_lt_ext
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The valve cover can let oil leak into the spark plug well. When you remove the plug the oil drips down the threads of the plug. So what it means is that your valve cover is leaking. It is usually not a problem.
I just replaced the SPs on my truck, and have the same thing. This happened to me once before, and that car had a bad head gasket after a while. I am not suggesting that's the same, but let's hope it's noting to worry about, especially that my truck drives great with only 75K on it. I will try to take it to a mechanic just in case and let you know of any updates.
 
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