2009 Hummer H3x
3.7L I5 130,000+ miles.

Recently just changed all the fluids, and also had an exciting experience with an exploding oil cooler hose. Thank you guys for helping me out with that.
After I got the trans oil back to normal levels and things were driving well, I started getting a terrible misfire. The misfire would come and go, totally at random. Hot or cold, rain or shine. It would happen randomly on idle, while on the highway, in my dreams, you get the idea. Although I did notice that if I was having the misfire and I made a turn, the misfire would go away… Idk what correlation me turning and a misfire going away has, but just sharing the information.

I had replaced the spark plugs about 10-15k miles ago, for misfires, and also found wet tubes then. To be honest I do not remember the brand. Although, I do remember that when I installed the new plugs, I used dielectric grease, and also used permatex white thread sealer on the coil pack bolt. Because I had noticed that the misfires would be more prominent during the rain.

So today I went and purchased some ACDelco 41-103 plugs, dielectric grease, and anti-seize(still had the thread sealer). Took the intake off and coils off and to my surprise, cyl 2 & 3 both were wet.. it could be oil or dirty water, hard to tell. Here’s is a link to the video: Click here

So before I continue, I just wanted to get feedback on what may be the issue here. Thanks!

 

water is getting past the hood vent and dripping onto the top of the motor running down into the spark tubes and collecting there. causes misfires. turning moves the water to the side making it work better. if completely full turning probably wont help any more. get the water out asap before it damages the coils.

 

WATER? GET THIS:


OIL? GET THIS:

 

I had to take care of some other things today, but I’ll be extracting the fluid tonight and keep you all updated.
What item is in the first picture?
I know the second picture is the vale cover gasket.

 

Send a paper towel down the hole and extract/check the fluid.

First picture found here: Coil-On-Plug Boot

 

Yes, I had same problem, especially when parked on driveway slope facing up. Some Silicon to seal the clips under the hood that hold fake air went solved the problem. I bet the water was in 1st cylinder form front

 

Thanks hummerz, will do!

the fluid was in cyl 2 and 3, but I guess anything is possible right.

Fingers crossed that it’s just water, don’t feel like doing VCG lol

 

Water comes in from the front too, I got a new set of boots, many years ago, still dry inside. Get a new set, to prevent water intrusion. If it's oil intrusion, try to re-torque bolts on the vc :89lb in.(7.416667 ft-lb).

 

I checked the torque for all the bolts I could reach on the VC and they looked okay. More than likely the spark plug tube seals going bad.
Used the paper towel to soak up the fluid, which looks to be oil, so looks like I’ll be doing the VCG tomorrow instead of relaxing

Just to confirm, there hasn’t been any reported Valve Cover failures on the 3.7L as there were in the 3.5L right?



The one on the left is a lot more dirty because it got stuck on the way out and was a hassle to get out lol

 

Yes, that is oil. I don't know of any vc failures? My vc & gaskets are still oem installed. I'll put that on my future to do list: Replace vc gaskets @130k.