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Where's all this @#$% smoke coming from?

Discussion in 'Dakota, 1998-2013 Durango and Aspen' started by DaveWR2, May 31, 2016.

  1. DaveWR2

    DaveWR2 New Member

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    Hello,

    I am new to this group. Having had my '90 Dakota from new and doing nearly all the work myself, I should be able to make some contributions. For now, I need some help.

    I am building a new 239 (3.9), but more on that later. In the meantime, I replaced a leaky lifter in the existing engine, without removing the head.

    When I fired it up, it smoked like a chimney. Assuming I had a leak between the intake and head allowing coolant into a combustion chamber, I reinstalled the intake a second time, being doubly careful, but with the same result.

    It occurred to me as I sat down to write this, maybe examining the plugs might help.

    Any ideas or advice would be great. Anyone else have the same experience?

    Thanks.

    -Dave
     
  2. valiant67

    valiant67 Rich Corinthian Leather
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    Where is the smoke coming from? Tail pipe or engine? The valve cover gaskets were bad on these - the studs for the valve covers (if present) need to be removed and replaced with bolts, assuming it's from under hood.

    Otherwise I think you need to lok at plugs, do a compressin check, cooling system pressure test, etc.
     
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  3. DaveWR2

    DaveWR2 New Member

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    Um.... Sorry-Out the tailpipe.
    I'm just looking at what changed, as in what I removed and reinstalled. It didn't smoke like this before.
    I'll pressure check and check the plugs.
    Thanks!
    -Dave
     
  4. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    The so-called 'belly pan gasket is leaking, the one under the intake manifold.
     
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  5. DaveWR2

    DaveWR2 New Member

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    That's what I was figuring, the metal ones between the heads and intake. The first time I used black RTV around all the ports, second time that spray copper. Followed the manual for torque sequence etc. Why am I having such a hard time getting these to seal?
     
  6. valiant67

    valiant67 Rich Corinthian Leather
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    This is a pre-Magnum motor. I don't think there's a belly pan on this one like on the 1992+ V6 motor.
    I'll admit I've never looked at the bottom of the LA 3.9 intake but I think it's like the old school 318, just the gaskets.
    If it's the gasket between the head and intake, it won't be oil as no oil flows from the head to the intake (or vice versa).
     
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  7. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Right, I missed the age.

    So, smoke coming out the tailpipe rules out any damage to the oil pressure sending unit, leakage at the distributor O-ring, PCV valve grommet, or any other external oil leak onto the exhaust or other hot metal surfaces. It's oil coming into the combustion chambers. And that comes in via bad rings, bad valves or valve guides, or PCV intake hose (if the PCV valve were stuck open and drawing too much vacuum on the crankcase). Which of these would be affected by removing and replacing the intake? And there is still a valley cover, isn't there, by which the lifters were accessed?

    Are the rocker arms reinstalled and torqued correctly? Might be worth a compression check, also.

    Oh, and is this white smoke (coolant), gray/blue (oil) or black (fuel mixture too rich)?
     
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  8. ImperialCrown

    Level III Supporter

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    Yes, we have to determine if this is coolant steam or oil smoke.
    RTV or spray copper doesn't usually make an acceptable substitute for a gasket. RTV shouldn't be used as a 'dressing' for existing gaskets. Silicone rubber derived RTV will dissolve in the presence of gasoline.
    There is Mopar Engine RTV which holds up better against gas and oil than most. It should be a dab at each corner of where the intake sits. It shouldn't be relied upon as a 'gasket'.
    Use of OEM gaskets will assure a quality seal. I have seen inferior gaskets break down in a short time. Gasket surfaces must be clean and 'prepped' in order to seal satisfactorily.
     
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  9. DaveWR2

    DaveWR2 New Member

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    Thanks!
    Sorry if I was unclear at any time.
    Although not convinced, I felt it was coolant since the smoke is white and it's the intake that was removed. Is this common?
    I didn't mean to suggest I used sealer in place of a gasket; I used it in addition to a gasket. I cleaned the gasket surfaces thoroughly.
     
  10. ImperialCrown

    Level III Supporter

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    Is this more than 'residual' coolant that may have gone down the adjacent intake ports when the intake was removed? It ran for awhile and didn't clear up any?
    Using RTV in addition to the gasket shouldn't be necessary with a good gasket, in fact it might cause torquing and sealing issues. You are using new, quality gaskets?
    I would think that the first place to look for a coolant leak into the cylinder would be from the intake-to-head joint.
    How do the #1 and #2 plugs look compared to the rest? Is there a coolant passage between the heads at the rear of the intake, or just at the front?
     
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  11. DaveWR2

    DaveWR2 New Member

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    Thanks.
    I was hoping it was residual coolant, but it didn't clear up after a couple times reaching operating temperature; I even drove it.
    The second time around, I sprayed a coating of copper gasket dressing on new Victor-Reinz gaskets.
    There are coolant passages at the rear too, but restricted by small holes in the gaskets. The gaskets are "handed" for this.
    I'll pull plugs as a next step.
    Thanks again.
     
  12. DaveWR2

    DaveWR2 New Member

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    So I pulled the plugs and found three that are light brown, two that are black and kind of sooty, and one that is black and kind of wet. The wet one came out of a hole that was covered in oil from a leaky valve cover gasket, since fixed. I doubt I got oil on the electrodes pulling it out though.
    I ran the engine with that wire off the plug and grounded with no change in white smoke out the tailpipe.
    I drove this truck for years with zero pressure in the cooling system. I wonder if I sealed the intake so well, I moved the leak to a head gasket. All test runs thus far have been with no rad cap, although pressure seems present now, at least until the thermostat opens.
    I pressure tested the system, but all that showed me was a cracked heater hose before I stopped for tonight.
    Since this appearears to be coolant steam, I plan to partially drain the coolant and run for brief periods with the water pump belt off. Good idea/bad idea?
     
  13. DaveWR2

    DaveWR2 New Member

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    As I was still trying to figure out whether the tailpipe "smoke" is coolant, rich mixture, or oil, I noticed that the smoke wafts out of the garage for about ten minutes or more after shutting the truck off. That's serious hang time for coolant steam I thought. Does coolant steam do that?? Thanks.
    -Dave
     
  14. ImperialCrown

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    Steam should dissipate fairly quickly. Oil smoke may not. Many times you can tell by the odor.
    Pay attention to oil-fouled spark plugs and the cylinders they came out of. Misfire will drive the injectors rich, so it can be a double-edged sword.
    Is there a good catalytic converter on this truck? The cat should 'incinerate' most exhaust smoke.
    Has a compression test or cylinder leak-down test been done?
    Zero cooling system pressure is not normal. The cap has to be on and the heat expansion allowed to take place. Fix all external leaks so you can diagnose any remaining internal ones.
     
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  15. DaveWR2

    DaveWR2 New Member

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    Thanks. Just trying to make an association with changing a lifter and the massive increase in tailpipe spew. Made many observations and still can't pinpoint it. I can check compression although I'm having a tough time making said association with a bad compression reading. Will do though. Trying to get her on the road until the new engine is finished.

    Thanks again.

    -Dave
     

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