Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter · #1 ·
OK...You guys probably remember my recent threads regarding overheating, etc. Long story short, changed the t-stat, didn't fix the problem. Came to the conclusion that it must be radiator. Also got a P0303 code (Cylider 3 misfire) and based upon the advice of several here, before yanking the radiator, I pulled the Cylinder 3 plug....Which leads to the title of the thread.

Pulled the plug - appears to have either oil or gummy gasoline on it. It was too thick to be DexCool, I think. Brown, slimy, and COATING the plug.

How screwed am I?

Gary
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
1,834 Posts
Does not sound good. Look through the hole at the top of the piston and see what is on it. Do a compresson check to see what all the cylinders are, replace the plugs and swap the coil with another cylinder to see if that coil is good or bad. After a few days check that plug again and see what it looks like.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #4 ·
I can't post pics yet as I haven't posted enough :(

That being said, the cylinder hasn't been firing for a few days, it the vehicle was probably driven 60 miles or so without that plug firing. Could it just be unburned fuel?
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,269 Posts
on higher mileage Trailvoys..
the hole the spark plug sits in-- may fill up with oil over time.
several of mine were like this when I changed plugs at 100K.
when you unscreww it and pull it out- some of it will coat the bottom part too as you pull it out.
this oil pooling is normal seepage past the seal on the higher mileage engines.
if its like this on your 5000 mile car.. different story.
 

·
Registered
Joined
·
16 Posts
Discussion Starter · #7 ·
I had to get it home - didn't have much choice. It has been sitting ever since though. I changed the plugs and now the Service Engine light is flashing, rather than staying on solid, which means it's the Coil Pack, right?

So, once I get this issue squared away, I will see if it has any effect on the temperature issue.

Am I tackling this in the right order?

Gary
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,269 Posts
unburned fuel in the cat leads to melted cats- since the unburned fuel combust in the cat.
 

·
Registered
Joined
·
137 Posts
OK...You guys probably remember my recent threads regarding overheating, etc. Long story short, changed the t-stat, didn't fix the problem. Came to the conclusion that it must be radiator. Also got a P0303 code (Cylider 3 misfire) and based upon the advice of several here, before yanking the radiator, I pulled the Cylinder 3 plug....Which leads to the title of the thread.

Pulled the plug - appears to have either oil or gummy gasoline on it. It was too thick to be DexCool, I think. Brown, slimy, and COATING the plug.

How screwed am I?

Gary
The slimy, brown, gummy spark plug is probably burned DexCool. The overheating and fouled plug indicates there is an exchange of combustion gases and coolant-coolant getting in the combustion chamber and exhaust gases blowing into the coolant passages. Sorry, but not good signs. You may need a tube of K-Y. The engine sensors must be picking up some bad vibes.
 
1 - 15 of 15 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top