Smoke where I don't want it...Fried Piston? Injector?

JayhawkLB7

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May 22, 2020
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Thanks in advance - I'm sweating it out a bit. Long story short: I noticed some coolant loss (IE: A puddle of it in my driveway this morning) and smoke coming from the engine bay at a red light on a 5-minute-away drive this afternoon. I got home, sprayed out the undercarriage and let dry to get a good look. Fired it up to run warm for about 10 minutes and think I found the spot. I believe that's my crankcase...but I'm a bit of a noob and could use some guidance.

The other thing is - I am getting a TON of constant smoke from what I believe is called the Blow by tube. From what I'm reading...this looks like an excess of pressure (and...smoke...) in the case, which probably feels like a burned out piston or on these LB7's possibly a bad injector? Please see video and photos below...thanks in advance for the terrible, terrible news, haha.

In the photo it's the seal between the casing top-most portion of the photo (orientation-wise that would be the driver's side...I think. I need to get a better look tomorrow in full daylight.
Blow By LB7 Vid.
 

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bimmer95

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Mar 15, 2019
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Coolant leaks from that area often come from the water pump.If it's coming from a small weep hole on the bottom of the pump it will need replaced.The blowby issue is likely a different problem although if a cup/injector pushed up that could be causing all your problems.

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RosWell

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May 30, 2008
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Definitely a leak in a cylinder somehow, whether head gasket, piston, rings or cracked injector. I'm with The Baconator on the head gasket. Probably need to do a compression test (didn't you do one before?) and neck it down from there. Whether or not your coolant leak has anything to do with it remains to be seen. Usually when you lose a head gasket it doesn't pool coolant on the ground. It turns it into steam. At least that's been my very limited experience. But my LB7 definitely had a head gasket leak, and it liked to disappear coolant. Is there condensation inside the oil fill cap after it cools?

The gentleman above me was very correct insofaras when the water pumps start to wear out they leak through weep hole right above there.

'twould help everyone if you put your truck's mileage and history in here. A botched injector replacement could also cause the blow-by...Like this
 
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JayhawkLB7

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May 22, 2020
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Yes RosWell - absolutely. So it's an '04 (LB7 obviously) with 237k on the clock. Kennedy Lift Pump, S&B CAI, Idaho Rob DSP5, PPE Boost Valve, that's about that. I've owned her for 3 years during which it's been my daily driver, though I've worked from home 80% of that time, and my 5th Wheel TV which is a 9000# 32 footer. We do Wolf Creek pass once a year, Monarch Pass twice a year, Ute Pass a dozen times a year, etc. (we pull heavy and we pull "up" on the reg, is the point). The truck has been fantastic in all conditions but I did bend a mess of rods (12 of 16 if I recall) and broke a crank key last. year almost this exact time (mid-March). New rods, new key, also went preventative at that time with new Fuel Filter and Housing, Alternator, Starter, both batteries...basically anything I could get to while I was tearing it out for diagnosis.

I took it to the most reputable shop I could find according to forums and reviews - they stated at the time that pistons, rings, etc. looked "good." This is of course the opinion of a mechanic which I took with some heart as it was a fine opportunity for them to make more money, which they chose not to do.

A full rundown; I've gone low coolant light about every two weeks since January. <1 liter to top off the reservoir each time. No visible leaks but kept looking. In the past two weeks I've seen a few drips, smelled coolant in the cab, and last week noticed enough smoke from the wrong side of the truck at a stoplamp to take a look. It had persisted by the time I got home...then I lost, oh, half a gallon of coolant in the driveway overnight (50 degrees out, not plugged in) the other day. That's when I went looking. I honestly didn't know that tube with smoke was even there before as I don't get my skid plate off unless I need to.

At any rate; that's where I'm at. I am not noticing any loss of power, weird sounds, shutters or bumps, etc. All feels and seems well less the excessive smoke and now the coolant leak.

Thanks again for all of your expertise. I've worked on gasser GM's since I was on the farm at 8 years old but this is my first diesel so I still feel a bit in the headlights at times.
 

JayhawkLB7

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May 22, 2020
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Ok Update:

- Water Pump: Yes. It does look like I've got a brilliant orange bubble just below the weep, and no higher. Given that and where it's landing (everywhere when the skid plates are one) - I can only assume your assessment is correct. Damn I wish I had done that while they were in there last year.
- Smoke: So I've read that a head gasket can be lightly assessed by an upper Rad hose being stiff as wedding d*ck the day after some use. Is there any weight to this? I only ask because there is no stiffness whatsoever in that pipe this morning.

But, that said, would a compression test tell most trained mechanics if we are leaning towards Head Gasket, Injectors, or Pistons/Rings? Any other indications I can make on my own? I have the whole day off, a little change in my pocket, and leave for Kansas for the weekend tomorrow morning so if I can do anything to do to limit my possibilities I'd be happy as a clam.
 
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bimmer95

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Mar 15, 2019
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Leaking injector cups and bad headgaskets often have the exact same symtoms.If the only symptom is pushing coolant and the Injectors haven't been messed with recently,it's more often headgaskets then cups.

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2004LB7

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Dec 15, 2010
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Shutting off injectors one at a time may help narrow it down to which cylinder is the culprit. Do you get the same amount of blow by from the oil fill cap?
 

RosWell

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Well it seems they beat me to the punch while I was flying today. A compression test can narrow down the side. Yes some diagnosis can be done with whether or not the head gasket is pressurizing the coolant system. There are test kits you can use to sniff the exhaust for coolant as well. and it is very true that head gaskets in my experience are more common a problem than injector seals/cups. Did they pull the heads when they replaced your push rods, or did they not? I guess in theory it could be done both ways. Just wondering if the shop might be at fault here. I'm guessing maybe they didn't pull the heads because you didn't mention anything about having studs put in, which is what most people do if they've got them torn apart anyway. However, if they told you that the Pistons look good without pulling the heads, they would have had to bore scope them. I've never had the displeasure of field-stripping the top end. I only assume that you could back off the rockers, swap out the rods, and put a new cam/key back in. Demonstrating my ignorance here. Also, a fair point if you did manage to buy EFI live as you had planned to before. You can shut down the injectors one at a time, and figure out which cylinder it is, or cylinders. Looks to me like something's definitely pushing exhaust into places where it shouldn't be.
 

JayhawkLB7

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May 22, 2020
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For sure Ros. I did not end up buying EFILive (because, you know, spent a $$$$$hittload on my key, haha). You make a valid point. My general assumption would be that they took a "good" look at the Pistons but I have no idea and didn't ask. If you'll recall I had our big 2-week Gunnison Mountain backwoods no cell reception camping trip to leave for 2 days before I got the truck back. That is showing my lack of diligence in asking teh questions I should have -- I was just happy to be able to not swap our 5th wheel out for tents and cots.

Ugh. As much as I like you guys, everytime we talk it always ends up costing me money, haha.
 

RosWell

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May 30, 2008
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I should be back in town tomorrow night. Like I told you last time, you can borrow my box. My truck is running like a Swiss top. All you have to do is buy the license if you want to program your truck, but I'm pretty sure you can do everything else without it. Like $Free.99. and you know I am on the receiving end of your job. It's not like I can't find you :)
 

RosWell

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Honestly if you plan on running that truck for a while, I'd find a used motor over on 105 at the salvage yard and have it custom built. but that's just me. Let me know if you find a stray LBZ sitting around :)
 

JayhawkLB7

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May 22, 2020
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And perhaps you are on the right track. I was certainly hoping to run this for at least "years" from now. Whether that be two or five perhaps it's time to stop running down one off failures once a year.
 

JayhawkLB7

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May 22, 2020
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Okay, so I'll have the opportunity to get it into the shop tomorrow morning for a legit testing but I did drop fluids this morning. No oil in the coolant and no coolant in the oil. I thought maybe swapping sauces was going on in there but it doesn't look like anything is getting where it shouldn't right now. really crossing my fingers on a water pump and injectors.
 

RosWell

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Yeah me too. It would be way easier to replace injectors than pull a piston with cracked rings I think. Too bad you can't just pull the valve covers off like you could in the old days.
 

JayhawkLB7

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So I have yet to get it in the shop as we've been remodeling so the truck has been off to the side of the house. With Camping season coming quick (AGAIN) I am snagging quotes. Used Pete at Front Range last time - they are looking at $5k. That's Injectors...not knowing if we have ring issues. I'm looking around for a reputable shop that may come in a bit lower but I'll probably end up using Pete. I *think* they did a fine job last time. I'm going to swap the water pump this weekend ahead of shop-time.
 

zakkb787

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Sep 29, 2014
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So, a few things regarding this and your other thread.
I’d suggest doing a compression test on all cylinders to see what your numbers are. This would tell you if a ring or piston is cracked most likely or if there’s another issue somewhere like a bent pushrod.
what are your balance rates? You say the emissions tests shows them on the way out but what exactly does this mean? What exactly did they say?
Coolant loss could be HG or cup related. My lb7 had a leaky cup I never could find till I pulled it all apart. Hard upper hose sometimes will show if the HG is out but not always the case. If you have the ability, doing the work yourself will save you a ton. Given that you don’t have a broke piston or ring, you can do injectors, head gaskets, water pump, and reseal your cups for the same amount or less than you’re quoted at the salvage yard for an unknown engine. The job isn’t as hard as you may think. I’ve done the top end on 2.5 out of the 3 duramax I’ve owned.
 

Bdsankey

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So I have yet to get it in the shop as we've been remodeling so the truck has been off to the side of the house. With Camping season coming quick (AGAIN) I am snagging quotes. Used Pete at Front Range last time - they are looking at $5k. That's Injectors...not knowing if we have ring issues. I'm looking around for a reputable shop that may come in a bit lower but I'll probably end up using Pete. I *think* they did a fine job last time. I'm going to swap the water pump this weekend ahead of shop-time.
Like stated above, I'd also start with a compression test to gauge the health of the engine. If the compression test comes back relatively even and within spec I would not hesitate to throw good parts in it.

Anything stopping you from doing it yourself? You can save a crap ton in labor doing the job yourself. It's a very time consuming job but if you take a lot of pictures and lay everything out in a manner that you understand then it shouldn't be too difficult.
 

JayhawkLB7

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May 22, 2020
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Swapping the Water Pump out this morning. Tried yesterday...failed miserably on the wake of breaking a WHOLE MESS of 1/2" breaker bars and ratchets. I'm using the tool method, I'm about to put the 400lb. air impact on (hopefully don't have to pull the radiator to squeeze in there) it and see if that gets the harmonic balancer off. If it doesn't, have any of you used the "bump" method? Just frame-railing the breaker, pulling the leslie tool and giving the engine a slight bump? That scares the bejesus out of me but at $1200 from the shop, I'm willing to do just about anything to save that extra grand...especially on the precipice of injector (or more) replacement.
 

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