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Blue smoke on morning start up

Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Our 2008 H3 was using coolant and there were no leaks. So I had a shop remove the head and check it for cracks. The sent the head and the gasket to a very well know local machine for inspection. It was determined that the head gasket was leaking between layers as the head showed no signs of any cracks.

The day after we got the H3 back it blew a large plum of blue smoke after starting it. It cleared out a ran fine. I called the shop and told them about this and asked if the machine shop put in new valve seals. They said they did.

So for the past week I have been taking this thing back to them so they can see it smoke. For days they would start it in the morning and it wouldn't do it. Every morning when I start it smokes like an old steam locomotive, but blue smoke. Finally one day it did it for them.

They are at a loss as to what is causing this. The good news is it no longer uses anti freeze.

Any help and suggestions will be greatly appreciated.

Thanks,

Bill
 

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alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
Is this an Alpha or I5? For an I5, that smoke was typically the sign of the head needing replacement. Common on the 06s but possible with other ones. But if the head's been rebuilt, I dunno. I hope some others with more engine knowledge that me will chime in.

Assuming it's the I5 and you have the stock intake on it, is there oil inside the plastic baffles that feed into the throttle body? Oil blowby can get past the PCV that's built into the valve cover and get pulled into the throttle body. That's primarily what happens on my 193,000 engine, and for me that blowby tends to occur when the engine has had to operate under a heavy load.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Hopefully it is PVC related. That would be an easy fix.

I also found this (see post #6 in the link), which goes along with AlRock (above) was saying ...but in a little greater detail.
https://www.coloradofans.com/threads/smoking-when-i-start-it.117117/


You should keep working to get it resolved so it doesn't (possibly) add deposits to your catalytic converter. You don't want to eventually get a code that says you need to replace your catalytic converter. That would probably take a while, but I don't know how bad your smoke issue is. (converters can be 'washed out' too but not cost effective if you're paying a shop)

Could also be a mis-installed valve stem seal, or a seal that has come off its 'perch' and is moving with the valve ..thereby letting a smidge of oil past. If inspecting the intake (as in the link above) doesn't lead to much, you might want to A) Pull off the pvc hose and just check the engine for 'blow by' as it's running and warm. Start there. Then, B) if it were me I would throw on a vacuum gauge and see what readings I get. This is just good basic troubleshooting that literally takes a couple minutes. Write the reading down. C) Pull out the spark plugs and note the color of the tips. Chances are good the offending cylinder's plug will be mis-colored (from oil). If they all look good (or bad) that also tells a story. If one looks bad (discolored or oil fouled) then you know it's probably a valve stem seal on that cylinder. Then, I guess if it were me, and I had the spark plugs out I'd D) also throw a compression gauge on each cylinder too (just to know b/c it doesn't take much effort to do). Make sure you perform the test 'correctly' ..a lot of guys don't. It doesn't take long to do ..but you can skip this if you don't have the tools (again, it's good basic troubleshooting). But if you found a cylinder low on compression, that could cut a lot of downstream screwing around and potentially weeks or months of headscratching ...and hundreds of $$ of unneeded repairs -- you'd know you have larger issues to deal with (like a valve not seating, or piston ring, etc). :) The more basic troubleshooting steps you skip, the less you really know. But in general, if it turns out a valve stem seal IS out of place or they forgot to install one on that valve stem (don't expect the shop to ever own up to it) ...the shop should be able to be replace the offending seal on the vehicle w/o removing the head. But it's a lot more work on an Atlas engine compared to a V8. Hopefully it will be an easy intake issue as in the link above.

It used to be real common in the old days on Chevy V8s that the valve stem seals when they only used o-rings, would get to a certain age and the seals would become old/brittle and crack and you'd get that 'morning puff'. At one point it seemed I was changing seals every once a month on mine and my buddy's cars LOL. Replacing is a lot easier on the V8's. I've also seen brand new seals come off their 'seats' when they weren't pushed on firmly enough from the start. So... there's a couple things to look into.

Hope it helps. Let us know what it turns out to be...
 
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H3Hummer

Well-Known Member
Messages
505
Location
LUXEMBOURG in EU
Ohhh bad smoke, know that from my old Zuk ...:whoa:and the head gasket was bad....oil and water, never a good mix. Did you have like mayo under the oil fill cap? If so, dont wait too long to check the cylinder head gasket
 

Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Thanks for those very informative posts! I do hope it's PCV related. Is it possible that when the shop replaced the head and gasket that they somehow incorrectly hooked up the PCV hose? I do know for sure that hose on right side of cam cover is on properly.

I am going to take this info to the shop on Monday.

Thanks again!
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Good luck. I hope it works out. They (the shop) just have to do good 'basic' troubleshooting and they should be able zero in on the root of the problem. That's what I outlined above. Not scatter-shooting a bunch of maybes ...that can lead ya down various non-productive (and expensive) rabbit holes. The more basic troubleshooting steps a person (or shop) skips, the less of a complete picture a mechanic has to make repair decisions (leading to potentially bad ($$) decisions). Of course, you're not there, so hopefully the shop will get it resolved. It might be something easy. (fingers crossed)

Good luck..
 

Exodus

Well-Known Member
Messages
91
Location
Alaska\Philippines
My experience with inline engines blowing blue smoke has always been either bad valve guide seals or worn rings

compression test will affirm or eliminate rings
 
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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
The shop said they ran something through the intake system that would clean out any excess oil in the plenum and runners. They had it for several days and said it doesn't smoke for them. I got it back Friday morning and seemed fine. This morning it blew out a cloud of blue smoke again.

At this point I am giving up on their ability to solve the problem. I will pull the spark plugs and do a compression test myself simply because I no longer trust them to figure it out.

I'll update this thread after I do that.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Did they actually determine if there WAS oil in the intake? or just flush it out (not knowing if there was oil in there or not)? Did they assess the intake issue or PVC if it was causing oil to get in? ....Is really oil smoke, or is it antifreeze? This shouldn't be too difficult for an experienced shop to make an assessment. Or maybe they did assess it and it looks 'expensive'. Sounds to me like they just flushed out the intake with something like a can of Seafoam. Based on what you're describing. Essentially reducing the chances it would smoke when you picked it up. LOL

Keep on them. Some shops try to sneak out of ongoing responsibility to correct work that shouldn't have occurred in the first place. They did the initial work, now there's an unforeseen issue which is likely to cost time/work they can't recoup. So they perform some procedure which is minimal and say, "we took care of it" and cross their fingers the customer never comes back. I'm not saying they're doing this, but it almost sounds like it. Stay on them. Get them to resolve it if you can. Unless you want to pay another shop to do it. Don't get overly upset, be extra nice but persistant ...try to get them to look into it. If you become a class A jerk (which is what I would tend to do) ...it will probably turn them off. I was in the construction industry doiing major projects and commonly ran into customer complaints that we had to resolve on our dime. It was a lot easier doing work for the customers who were firm but relatively pleasant, vs those who were jerks. But sometimes guys would have to get to the Jerk stage to get us back out there to remediate. (then they would get nice when we were there).

This shouldn't be that difficult to get to the bottom of (but could take a LOT of work to resolve). The worst case is they might have to remove the intake and remove the valve cover and inspect the valve stem seals. If one or two valve stem seals need to be replaced, it would be quite a bit of work. Yeah, you can pull out the plugs right after you start it up (and it blows oil) ...and see how they look. It would be in your best interest to try to get them to continue to do the work.

If they're good, they'll take care of it thinking you'll come back for future work. If not they'll eventually say, "Well, this isn't related to our work ....it's going to cost another $xxx amount to resolve." Then you have to ask yourself, "Is it worth it for me to get it fixed? Or do I want to take it to another shop and pay the same or (likely) more?". Or go into Jerk-mode.
 
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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Here it is Sunday about 12:40 PM. The Hummer sat for 18 hours. When I started it, it puffed out nice big cloud of blue smoke. It does it for me every morning, yet the shop says it doesn't smoke for them. I think they are outright lying to me. So I have a plan. And I have not gone into jerk mode yet. I will take it back to their shop some evening and park it front of their office door. Then I'll go home and take the keys with me and return in the morning. When it fills their office with smoke maybe they'll have to own up. If they don't then I become a jerk.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Not a bad plan. Let us know how it goes.

Is this an independent owner-operated shop? Or a chain? If a chain, might be worth finding out who the area mgr is and have them meet you there. You should have a buddy or wife with you as a witness. And they're not as likely to be a jerk back in front of your wife/gf, etc (no guarantee but....)
 

Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
They are independent shop.

Update. I removed the air filter housing, the air box, the throttle body and got a good look inside the intake plenum. It is coated with oil. I also removed both PCV hoses from the cam cover and blew air in them. They are open.

So why is it sucking oil out of the cam cover into the intake manifold?

Pictures attached.
 

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deserth3

Well-Known Member
Messages
1,069
Location
Conroe, TX
The h3 didn't come with an actual pcv valve. That's supposed to be taken care of by something inside the valve cover. Baffles I believe. On my h3 they didn't work well.
If just go get a pcv valve and put it in line the vent hose and see if that helps.

Sent from my SM-F711U1 using Tapatalk
 

Exodus

Well-Known Member
Messages
91
Location
Alaska\Philippines
ahh well since the oil is before the engine you just might get lucky ???

once had an air filter that was plugged up,so it started sucking oil thru the pvc valve

check your air filter :) good luck
 

Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Installing a PCV valve in line might be a good idea. Only problem is the line it would have to go in is a steel tube. The end of that tube is a rubber connector that goes on the left side (cars left side) cam cover. Inside that rubber connector is some kind of little rod. What I didn't was spray a cleaner in there. Maybe tomorrow.

I had checked the air filter early on in this mess. It's nice and clean.

And, what goes here? This brass threaded insert is on the side of the intake, down low behind the battery box.
 

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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
No more smoke!

I removed and plugged the vacuum line that goes from the intake manifold to the cam cover and ran a hose from the cam cover down along the side of the engine. The PCV system is now one like a car from the 1950's. It just vents to the atmosphere.

Everything is working just fine this way. There is no smoke or vapors coming out of the vent hose I installed. This makes me think the problem must be the baffles inside the cam cover and I will not be removing that to verify.

Thanks for all of your comments.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Hope that resolves the issue. This would seem to prove that valve stem seals aren't leaking. Nothing magically makes that go away except new seals. Now to tackle the root intake issue perhaps.

A major issue of those engines of the 50s and early 60's was you tore one down at 80k and they were full of sludge and carbon deposits inside. Enough that sometimes oil return drains would be restricted down to the size of a construction nail. So keep an eye on things as miles pile up ...if you can look inside under your add-oil cap.

But for now, that's a positive step forward.
 
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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
I'll keep an eye on what's under the 710 cap.:giggle: Those engines of the 50's/60's ran on leaded gas and used old style dino oil. Unleaded fuel and synthetic oil should keep things clean. I think it'll outlast me.

Thanks again guys.
 

Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Here's an update and two questions.

After driving the Hummer nearly three weeks with PCV hose disconnected and plugged there has been no smoke. However, the underside of the 710 cap developed the expected milk. Two days ago I reconnected the PCV hose and, presto! I have smoke in the morning. The 710 cap lost it's milk.

I am convinced the problem is with the baffles in the am cover. I now want to order a new cam cover. I am sure the GM part number is 12631008 but every listing for that number comes up as Colorado/Canyon. Before I spend money I just need to know is this correct item?

Second question. A while back, after getting the Hummer back I wanted to do my own compression check. When I treid to remove the spark plugs, using a standard 8" ratchet wrench, I couldn't move them. So I stopped fearing that getting a breaker bar after them might strip the threads in the head. Is my fear justified? And if so, what would you recommend I do to safely remove the plugs?

OK, that was three questions. As always, your help is appreciated.
 

H3Hummer

Well-Known Member
Messages
505
Location
LUXEMBOURG in EU
The last time i saw Milk at the oil cap, i replaced the cylinder hood gasket. Smoke , blue smoke and milk mix is most of time the sing, that water or coolant is mixing with oil. This is only possible when your cylinder hood gasket is bad.
My problem was solved by replacing it, no more smoke since then.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
The 'milk' is moisture (condensation) mixed with oil. Warm moist air tends to rise therefore you see it under the cap where it gets trapped. Of course you're going to have that by removing your pcv -- you've dramatically reduced the 'ventilation' in your crankcase. That's the whole point of the PCV. It's also going to eventually load your engine up with gunk too (even though some guys say it won't) ..because you're not pulling airborne deposits out.

But H3Hummer could be right that it could still be a headgasket. That's why someone needs to do some basic troubleshooting. Headgaskets can fail catastrophically, or they can (and quite often do) go gradually over time. And by "Time" I mean, it could be a week, 2 weeks, months or several yrs (yes). What usually happens is the layers of the headgasket delaminate ..kind of like pages of a magazine that get wet, don't lay tight anymore -- even if you press the magazine down. And/or the metal ring of the head gasket around your cylinder can crack or corrode allowing a small amt of coolant pass. Generally when a headgasket is failing a micro-amount seeps past over time after you shut the vehicle off ...due to the cooling system's pressure. It only takes a small amount to create smoke. Then one day after a lot of cycles, the issue has gotten worse, the dam will break and you'll have solid coolant into a cylinder and constant smoke out of the tailpipe. Almost every head gasket I've removed due to a head gasket failure you can see right where the leak occurred.

I've personally owned a few vehicles that exhibited h/g symptoms for years before the headgasket finally let loose big-time. Right now my land rover has failing headgaskets and has had symptoms for several yrs probably 6-7 years: Gurgling heater core, consumes some coolant, slightly over-pressureized cooling system, Rarely but sometimes blows smoke on start-up (not oil smoke). I don't drive it much so I just put it off till it really needs it. I loosened the radiator cap some so it doesn't put any more strain on the cooling system and really 'blow' the hg (i.e. push through the head gasket weak area), or blow a hose/radiator, etc. Lack of pressure prevents coolant from being forced into the cylinder after ya shut it off. Since it's just a 'fun vehicle' and all my few summer miles are highway miles, it doesn't hurt driving it with the cap on the first 'stage'. The engine would overheat sitting in traffic, probably, but that's not how I drive it. I've driven vehicles with blown hg across multiple states (in the old days) with the radiator cap loose. Just because an engine is ill, there's no reason to murder it (LOL). Maybe next yr I'll pull the heads off and install new headgaskets and fix it once and for all.

That might be something for you to try too: loosen the radiator cap and let it sit for overnight and try it in the mornings (don't scald yourself). Maybe it's not oil smoke after all. That's why I saiid to look at your spark plugs and do all the other troubleshooting. Look for air bubbles in your radiator, and sniff for combustion gasses. Zero in on if it's definitely oil or coolant. It might be oil and you might need to pull the intake and have a look if you haven't already.

I know it's a pain. Hope you zero in on the issue. Might happen to my H3 too one of these days, so I'm 'pulling' for ya. Definitely keep us up on your journey till you fix it. Might pop over to the Colorado forums bc they're pretty active: a lot more Colorado owners.
 
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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
I suppose it's possible that the new head gasket (and shaved head) failed the day after the shop gave it back to me but somehow I doubt that. And with the PCV hose disconnected and plugged it does not smoke. So I am going to replace the cam cover and see what happens.

I'll keep you updated.
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Maybe they put it on backwards or upside down? (if that's possible on this engine)

On many engines (maybe most) it's real easy to make that mistake. The bolt holes and cylinder bores are symmetrical -- the head gasket will fit either way and the bolt holes and cylinders will line up BUT ...BUT there is a subtle difference in coolant passage alignment (close ..but not quite). Even so, hg's almost always have printed on them "this side up" with a Forward arrow. I have no experience if the hg can go on 'wrong' on the Atlas engine as I haven't changed one yet (someone else plz chime in). Probably worth asking that question, or maybe someone here will chime in who's replaced theirs. Usually if ya put one one you won't have a coolant leak, it'll just block a water passage. So that might not be it. It's hard to say.

Maybe they didn't torque down the head right or to spec? Or maybe the head is cracked (the original problem) and the crack wasn't properly detected? Maybe it (or the intake) slid off the fender when the guy pulled the light cord and it bounced onto the concrete? I've seen that stuff happen before. Maybe the head gasket was bent in the pkg when the parts store guy brought it over? Maybe they put it together and warped the head bc the guy forgot to put coolant in the engine when he test drove it? Probably none of those things happened but hard to rule anything out.

I actually did that myself one time. I am usually very thorough, but this one slipped past me: I had a Toyota 22R head completely rebuilt (after a chain guide failure) in a Toyota 4x4 back in the day. Put it on and put coolant in it, ran great. Test drove it up and down the road, then parked it outside the shop on the gravel ....to come back and finish it up in a couple days when I had more time. Well, unbeknownst to me, there was a small coolant leak at the lower radiator hose, which I didn't see. I knew it was kind of a weak hose, but I forgot to order a new one so ran with my old one. Well, in the course of a few days I surmise (looking back) all the coolant slowly dripped out. But ya couldn't see it on the grass/gravel below (well I noticed it afterward when I looked). I didn't bother to re-check the coolant before test driving it the 2nd time like I should have. Tickled with my work I jumped in, drove it up the road a few miles and by the time I got back I had Re-warped the head again! Dang. Cost me another $400 to have it inspected and unwarped plus another set of gaskets! And another week of waiting (between working, etc). LOL. Now I always quadruple-check those kind of details after major work. The point is, things happen and mistakes get made.

Have you been searching the Colorado forums where there is a lot more posts/activity?
 
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Aridgerunner

Active Member
Messages
25
Location
Pennsylvania
Jeepwalker I thank you asking if I looked into any of the Colorado forums. I had not. And now that I have I have no doubt that the problem is the baffles inside the cam cover. I read several posts and watched a few Colorado videos in which cleaning the baffles inside the cam cover solved the problem. In one lengthy video the guy removed the cam cover (I'm gonna hate that job) and thoroughly cleaned the port and ran Seafoam through the port several times to ensure the hole/holes in the baffles are open.

So I have some work to do. The one video said I could expect to take about 1 1/2 hours to take it apart and about an hour to put it back together. Knowing my luck this will take all day and probably a few cuts on my hands.

I'll post an update after completion. Which might be a while. I'm in no hurry.
 
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