Working on the smoking issue

[alrock]

I'm trying to figure out the Hummah's smoking issue and no, it has nothing to do with Marlboros.

When climbing up steep grades the oil of course moves towards the back of the engine. The problem on my truck is that is isn't draining back down properly and some of it ends up getting combusted with nice plumes of smoke out of the tailpipe.

I spoke with Dave at Royal Auto in Tucson, and his main Hummer guy Nick, and they suggested it may be a PCV issue. Only problem? The PCV valve is a part of the valve cover on the H3. It is not an independent part. You have to replace the whole valve cover.

Their suggestion was to spray brake cleaner in the two holes in this pic towards the firewall. The hose on the left is the one where oil is getting into the resonator and intake. You can also see that at one point oil simply leaked out and dumped on the engine. That would explain the cloud of smoke from under my hood at Cleghorn Ridge last month when I started my engine. The thinking is that the port on the right hosting the PCV valve below the elbow (mostly hidden by the hose in the 2nd picture) is clogged so liberal use of brake cleaner may do the trick.

So, I've done that part and we'll wait and see how it works.

I'm keeping an eye on the valve cover. You can see oil buildup here (the very top was already cleaned) and this is likely just from the purge out of the top. I've cleaned this area and will look for any new leaks. 3500 miles left on powertrain warranty.

While I had the resonator off I did a quick wipe of the throttle body. This is about 6-8 months worth of buildup for me. It should be (and was after wiping) silver and shiny

And I figured I'd do my plugs again. It's only been 22,000 miles, about one year, but I wanted to see if there was any damage. Plus I forgot anti-seize last time I put in new plugs

They are in order L-R, front to rear, 1-5 (I assume). Notice that #2 is much lighter than the others. I don't know why

And just to keep the truck happy I had Royal change the oil and turn the front rotors. Then Luis and I installed an iSimple iPod controller in the Hummah. That unit is awesome!

(Please pardon the one loose coil bolt. I always loosen that one when removing the resonator thinking that is one of the bolts holding the resonator.)

 

[M22KLARS]

How about adding a catch can like I'm about to do? You can add one for around $90.

 

[M22KLARS]

Brodie's boys at 3GCustomz have the Big Bully CC's for $90 shipped right now. They are marked as Blemished.. but they seem real minor.

 

[alrock]

Been thinking about the catch can but I can lose over a quart of oil in a day. Need a mighty large can.

 

[M22KLARS]

Holy **** Alex

 

[3Hummers]

Geez, noticed any big dark puddles under Hummah? The 98 was starting a little hard and smoking some so I changed the glow plugs last trip to Texas and solved the issue.

 

[f5moab]

Quart a day, through the PCV or the pressure hose?????????

Have you performed or had someone performed a compression test? And then an air leakdown test?

I believe if you remove the intake cover you will find a baffle and some holes in the baffle under the PCV opening. If those holes are plugged, oil can't flow back, thus it gets suckec up into the intake. Not sure if squirting some brake cleaner will work. Might, but might not. Might try soaking to allow the holes to clear.

But still a quart?

Is this just when off-roading or for normal use too?

 

[alrock]

Only occurs on those steep hill climbs. Mostly offroad but can be long, steep highway. The tech agreed the brake cleaner might not do the trick but we had to start somewhere. Taking off that cover may be a bit beyond my skills.

 

[LagunaH1]

I realize that I am 99.6% clueless about this, but a quart a day sounds like an awful lot. When I frist heard you talking about this, my laymans brain always wondered about something going on inside a cylinder. Given you are so close to warranty expiration I think it would be a *very* good idea to do the compression tests as Doug is suggesting. IF there's something going on with the pistons / block / heads it would obviously be best to get it covered under warranty

 

[06 H3]

holy ****! a whole quart! Hope you get this resolved before you hit 100K

 

[Portager]

I agree with Doug about the compression test. You might also try calling Mike at Tustin Hummer. He is the best Hummer mechanic I know.

 

[theBroken]

If your loosing that much I would be concerned no matter when it was happening. Go get a compression tester, they are cheap and you will find other things to use it on so they are nice to have. Check each cylinder separate, write down what each one is. They should all have around the same PSI (it won't be dead on). Doubt this is the issue but might as well check. It's not always horrible like bad rings and bent valves, you could just have a bad seated valve that a bit of cleaning would fix (like BG cleaner). Remove your TB and clean it out real good, don't use brushes just clean it with carb/TB cleaner and a micro towel. Hose out your air intake real good so the front end of the system is clean. Then run some BG cleaner through the intake and get all the crap out of it. This could actually fix your issue if it's just build up under a valve that's not getting shut all the way. The BG cleaner will get rid of the build up.

 

[Hunner]

I'm concerned about the suggestion of spraying brake cleaner down that PCV fitting! You know where that will end up?
I would not do that without removing the valve cover so you do not dilute your oil. Way too much "however much that is" could wash down the cylinder walls and other surfaces. Sort of as scary as old old guys claiming running kerosene thru your engine via the oil filler, cleaned it up, not really a good idea. Rings and bearings won't like you.
We used to put baffles in oil pans for tight road courses to keep the engine from starving for oil in high G corners. I have not seen an H3 pan off, I wonder if we have a baffle around the oil pickup for extreme angles of operation??
If you do have badly worn or broken rings on one or more cylinders or bad valve guides or seals the extra oil when tilted will just make it suck up oil more easily.
Like Brodie says, a compression check may give an indication if one cylinder is lower than the rest.
However by looking at those plugs if it was a problem in a cylinder that plug should show signs of wetting out with oil if it was really bad. Marshmellow brown is about right, lighter usually means leaner burn.