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Glowing Manifolds/bleeding tranny

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by newyorkin, May 10, 2001.

  1. newyorkin

    newyorkin 1 ton status

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    Hey everyone.

    This question requires a little background. I had a slow leak at the tranny dipstick grommet that showed up last weekend (it was chewed up and sticking out for some reason). I figured I'd fix it this weekend, since it was a slow leak. I drove her about 40 highway miles last night, and as I was exiting the highway, I lost incredible power, and the lifters were making the motor sound like a friggin diesel. Every guage read normal. I limped to 7-11, checked it out, and the manifolds were bright red. Oil level was normal, color was normal, evrything looked hunky dory. I sarted it again, and I swore it sounded like was running without oil, but I was at 10PSI in idle! I let it sit, poured in another quart of 10-w40, started it, and it sounded perfect. I drove to my destination, heled my buddy move, then on the drive home, the tranny started emptying, and the motor started screaming. Eventually got it home (stopping every 10 minutes to pour tranny fluid out the window, since any thing I poured in the dipstick tube ended on the highway anyway).
    So here's my question:
    Why would the exhaust manifolds get so hot they glow? Timing is correct on the truck, and exhaust appears to be flowing. Is it possible that running at such a high RPM on the highway just heated it up? I can't imagine that being ok...

    '88 K5 Silverado 350/700R4

    Ratch
    I could swear there was a trail around here... Right around where those new condos are...
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    I believe that too rich or too lean can cause this problem, as well as timing. (combustion in the manifolds, or heat from lean condition running, migrating to the manifolds) How that could be related to the noise, not sure at all.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  3. Blazer1970

    Blazer1970 1/2 ton status

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    Lean or late is the rule for hot manifolds/headers. Either a really lean condition (big vacuum leak or malfunctioning fuel injection) or severely retarded timing. On your truck, something to do with the knock sensor/ESC stuff could retard the timing (knock sensor telling the computer that the engine is knocking when it's not, or picking up another engine noise and thinking it is a knock).

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  4. muddin4fun

    muddin4fun 3/4 ton status

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    Would tight valves do that also?

    [​IMG]
    <A target="_blank" HREF=http://k5chevyblazer.homestead.com/home.html>http://k5chevyblazer.homestead.com/home.html</A>
     
  5. newyorkin

    newyorkin 1 ton status

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    Ok, it begins to make much more sense now. The knock sensor wire was zip-tied to a spark plug wire when I got the truck, so when I tuned it up a couple weeks ago, I un-zip tied it and let it hang free. I totally forgot, I got the check engine, and read the codes last night when I finally got home. I had the knock sensor trouble code, and esc trouble code (caused by the knock sensor I guess)! But I vaguely remember something in the book about the oxygen sensor, don't remember if it was a trouble code or the book's suggestion on correcting other trouble codes. When I did the plugs during the tune-up, I did mention to myself that the plugs looked like she was running a little lean. Then I promptly forgot about it... I will check and correct the wiring for that puppy tonight... After I unload the ATF-soaked new furniture... I guess it was a coincidence that the tranny turned into mt. st. helen when the engine went nuts...

    Also, is it possible or recommended to clean the o2 sensor? I ask because I usually find I need parts when the parts places are closed, and I'm afraid that may happen tonight...

    Here's pictures of the damage that I shot real quick last night:
    <A target="_blank" HREF=http://k5.8m.com/dipstick.htm>http://k5.8m.com/dipstick.htm</A>

    Thanks for the tips, btw! Been using this site for 2 years, and nothing on the web comes close to serving the K5 community like cK5!


    Ratch
    I could swear there was a trail around here... Right around where those new condos are...
     
  6. Butch

    Butch 1/2 ton status

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    One other thing that will make the headers glow like that is a stopped up catylatic converter. I had that happen with a s-10 blazer. It felt like exhaust was getting through, but it was not enough. Total loss of power and all gauges read just fine. It happened to me from running into an iced up mud hole in the middle of the winter with a hot exhaust. You need to find out fast though your motor will not tolerate much of that before the oil loses viscosity and you start leaving parts on the road behind you.

    I thought I was wrong once,
    but I was mistaken
     
  7. CV202

    CV202 1/2 ton status

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    Your O2 sensor needs outside air to measure against. Check that the hole in the sensor case is free of obstruction (mud, crud or ATF). The kicker is that you're not supposed to use any chemicals on the sensor as it can mess up the calibration. I'd recommend just spending the 20-30 bucks and changing it out. It's a pretty easy job.

    Why do people keep calling it a Bronco!!!!! [​IMG]
     
  8. newyorkin

    newyorkin 1 ton status

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    I think I'm going to do that, buy and swap out the o2 sensor if I can't find the trouble.
    Tranny leak (or opening) is fixed, and she's back to shifting like new, but the engine is still running like crap.

    What are the causes of this:
    late pedal response/surging
    bogging/surging
    bogging (out of the blue) at normal driving rpm
    lean mix

    On the brighter side, the trouble codes have not resurfaced the last 2 hours of driving.

    I'm leaning (pun intended) toward fuel filter, but the bogging/surging is too consistent for that. When I accelerate form dead stop, it grumbles and moans about it, then suddenly perks up and shoots forward, running perfect. This happens consistently until it hits normal temp. The cap/rotor/plugs/wires are all new, high perf stuff. I've run fuel system cleaner through it with one full tank last week.

    Ratch
    I could swear there was a trail around here... Right around where those new condos are...
     
  9. muddin4fun

    muddin4fun 3/4 ton status

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    That sounds like timing to me.

    [​IMG]
    <A target="_blank" HREF=http://k5chevyblazer.homestead.com/home.html>http://k5chevyblazer.homestead.com/home.html</A>
     

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