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350 Chevy engine Question

Discussion in 'Off Topic Threads' started by JayZap, Feb 21, 2013.

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  1. JayZap

    JayZap Active Member

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    I have owned, since new, a 1997 Chevy Tahoe with the 350cid V8. Just recently I notice when the engine is first started a valve tap. The valve tap goes away (almost) in a few minutes after starting. The Tahoe has 130k easy miles on it, and the oil has been changed religiously every 3k miles. (Wolf’s head 10-30)

    I checked Chevys web page and it stated this is a typical problem with the 350, and the _GALLEYS_ should be cleaned or the oil pump replaced. The oil pressure has not seemed to have changed (dash gauge)

    My question is: what the heck is a GALLEY, and how do I clean it, or is it a trip to the Chevy dealer?

    **Edited for spelling**
     
  2. Catpower

    Catpower Molon Labe TS Supporters

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    Gallows are the paths that are cast in the engine for oil to pass through to lubricate the different parts

    Sometimes they can get plugged with crud

    I would bet you just have a leaky lifter
     
  3. steele

    steele TS Member

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    That sounds about right. You have a lifter that leaks down & needs to have oil replaced to take up any extra clearance. Supposedly there is an engine flush product that will help clean up the extra crud & gunk that collects internally.
    You drain the oil, pour in the cleaner, let the engine run for a set time, & the drain engine. Re-fill with oil & new filter. I have never tried it, but it is available. I can't see it hurting anything, being the engine will be running with a lube. Butch from Pgh
     
  4. Flinch king

    Flinch king Member

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    Are you sure that the noise that you are hearing is not piston clearance movement from the engine block. I have a 97 Tahoe also, and when it is really cold I hear a small amount of piston rattle from the back cylinders. This was very common for those model year engines. It goes away after a minute or so due to the piston heating up - normal condition. We also have any engine flush machine here at the shop for cleaning the inside of the engines. I recommend that this be done every 40,000 miles due to contaminates and by products from the combustion process. Again this is a normal maintance procedure that we use as preventive maintance. It will also increase horsepower back into the motor which will increase fuel mileage.

    Hope This Helps,

    Brian Seibert - (Flinch King)
    State Of Ohio Mechanical Advisor
    Ohio Vehicle Repair Board
     
  5. Bruce Specht

    Bruce Specht Well-Known Member

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    It could be piston slap however the flush is the place to start. In the past we'd used disel fuel to flush but buy the product made for that problem and follow the instructions.
     
  6. mx2005

    mx2005 TS Member

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    I would not jump into a bag of warms unless you are sure of the problem or you will increase you're trouble and cost if it is going away turn the radio up before starting once it heats up it will be fine Flinch King is right they had a liittle more clearence in the blocks ,I would have to say from most likely being made in Mexico.Keep changing you're oil on time and drive it .
     
  7. scooterbum

    scooterbum Active Member

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    I have a '98 454 with a leaky lifter on startup. Dealership wouldn't fix it under warranty, claimed they couldn't notice the problem.
     
  8. Catpower

    Catpower Molon Labe TS Supporters

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    If it's piston slap don't worry about it, just order a new engine as the one that is in there won't be running very long, plus if it is that worn out you would be dumping oil in it very often

    It's just a leaky lifter, the cleaner might help it out, but maybe not, it will run without a problem for quite a while unless it has a roller cam then you might want to get it looked at but that is highly unlikely
     
  9. JayZap

    JayZap Active Member

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    Thanks guys for your replies. The darn thing runs great and uses no oil at all between changes.

    I hate to think of trading it in, but it may be time. I've heard that these things go 250k and more. I'm suprized it's going south, because i took very good care of it.

    Thanks again
     
  10. Catpower

    Catpower Molon Labe TS Supporters

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    When I was blowing and going in bidness we had a fleet of about 140 of them and although I am a Ford man 350's were some of the best engines ever made, it wasn't rare for us to get 300,000+ before scrapping them, or should I say selling them very cheap, the guys were kind of tough on them

    Had one that made 415,000 miles on it it was still running fine
     
  11. need to shoot more

    need to shoot more Active Member

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    I have a 99 Tahoe with 136k and the 350 on cold mornings 30 or less there is a slight tap on start up but clears up rather quickly 30 seconds or so
     
  12. WesleyB

    WesleyB Well-Known Member

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    All of the above and 15-40 oil. My 2cents worth.
     
  13. Ross

    Ross Well-Known Member

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    As most have said, probably a leaky lifter my last one started that at about 125,000-- 150,000 was still doing it when I traded it at about 250,000. That's a good brand of oil that you're using just keep changing it regularly. Ross Puls
     
  14. Stl Flyn

    Stl Flyn Well-Known Member

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    Have a 98 GMC. It has been making that noise in the winter since it hit 75,000 mi. on start-up. It has always been the right side that I have heard of. I now have noticed however that the donut seal between the exhaust manifold, and pipe connection is leaking. Makes a very similar sound, until the the seal heats up enough. It still makes the noise on heavy acceleration, with the higher pressures.
     
  15. CalvinMD

    CalvinMD Well-Known Member

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    I'm not familiar with Wolfs head motor oil but if it were my truck...I'd put CD2 or Marvels Mystery oil in and run until the next oil change..and then use a quart of 50/50 mix of K1 kero and auto tranny fluid and run it for an half hr or so on a varying fast idle..then drain the pan and before putting oil in start it for 30seconds or so long enough to hear the lifters deflate due to lack of oil pressure...then let it sit for a few minutes then pull the pan plug again to get the last oil out that was pushed out of the lifters by valve spring pressure and settled in the pan and hopefully took a bunch of dirt and crud with it...then fill the crankcase with a good synthetic or synthetic blend hi mileage formula oil..If your weather is a really cold morning type of place dont go any heavier than 10-30..5w-30 would be best...heavy thick oil just takes that much longer to get pumped to the lifters because it flows so slow when cold....I've cured a LOT of lifter tap problems for others using this method
     
  16. oz

    oz Active Member

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    try a can of marvel mystry oil and just drive it till next oil change.
     
  17. scooterbum

    scooterbum Active Member

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    I doubt that cleaning will cure a lifter problem. I think the lifter has a tolerance problem, as in too loose.
     
  18. lightning20ga

    lightning20ga Member

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    ur is that cheap oil is junk mobile 1 never hav a problem try a gd motor flush first then 5 30 full syn high milage
     
  19. steele

    steele TS Member

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    If the lifter was too loose, as in too much bore clearance, he would have lower oil pressure, as the oil would leak around the lifter bore. It just sounds like too much valve lash clearance until the hyd lifter pumps up to take up the extra lash.
     
  20. blizzard

    blizzard Active Member

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    I thought the piston slap issue was on the 5.3 and 4.8 engines? Also, and I'm not trying to start an argument, but I absolutely would NOT do what CalvinMD suggested. If it were an old pre '85 small block that's one thing, but I wouldn't do it on a newer engine. JMHO
     
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