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WAY O/T-Chevrolet valve clicking

Discussion in 'Uncategorized Threads' started by snapthecat, Mar 11, 2007.

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  1. snapthecat

    snapthecat TS Member

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    I have a 2000 Silverado. 54,000 miles, Started a very very loud valve clicking sound when cranked cold, lasts for about 30 seconds. Changed from Havoline 10W30 to 10W40, still the same click. Something must be wrong--what is it?
     
  2. Brian in Oregon

    Brian in Oregon Well-Known Member

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    Either a sticky lifter that degums itself as it warms up, or it's starting to fail and will eventually collapse.<br>
    <br>
    We USED to just add a quart of tranny fluid to a hot engine and run it for a little while to clean out such problems (and not under heavy load), but with newer engines I dunno if that can be safely done anymore. Some oil service places have special engine cleaning additives (detergents) that can degum lifters.<br>
    <br>
    Otherwise the lifter will need to be replaced. Some engines this is very easy to do, and others are more complex.
     
  3. fssberson

    fssberson Active Member

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    Yes, I had a 2003 Yukon XL, 350 c.i. that did the same thing when warming up. It was new and the dealership said that was what it did. Ran for 80,000+ miles and it only did it in cold weather starts... Traded it in for amore fuel efficient car. Fred
     
  4. skip

    skip Member

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    Go to the web site above, it explains it all.

    http://www.pistonslap.com
     
  5. Bruce Specht

    Bruce Specht Well-Known Member

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    Buy yourself 2 new oil filters and a gallon of diesel fuel. Drain the oil repalce the filter and add the diesel. Let the truck idel for about 5 minuets (do this outdoors) then drain the oil and replace the filter replace with 10W40 then see if the valve still knocks on start up.
     
  6. B V

    B V TS Member

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    I was on vacation in Oregon and had my big block Suburban's oil changed at a Texaco station. Havoline 10-30. Valves were noisy until I got to British Columbia. I changed the oil to a "CD" rated oil called Essolube DX and never had another sound. Changed to Mobil I when I got home and all was good.
     
  7. baflstang

    baflstang Member

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    Are you sure you are using the correct weight oil for your application? Sounds mighty thick to me. 5W-20 or 5W-30 seems to be closer to the norm with the new designs in today's engines. The closer tolerances of today's engines demand a thinner lubricant. The clearances are so close that the thicker oils of yesteryear will not get through quick enough causing oil starvation. Surely at this low mileage the engine is not worn out. Bill
     
  8. Beretta687EELL

    Beretta687EELL Well-Known Member

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    I have a 2000 Silverado which developed a cold engine "tick" or "knock" at about 25,000 miles. I was told that this is "piston slap" and that is somewhat normal in a cold Chev engine during cold (sub-freezing) temperatures. As I understand it, the pistons are somewhat elliptical, until they get warm and then they conform to the shape of the cylinder. I don't get the noise in the warm weather or if the oil has just been changed in the cold weather. The engine now has about 155,000 miles on it and just like the Energizer Bunny it keeps ticking and ticking, but just when the weather and the engine are both cold. Bill Malcolm
     
  9. Texas Ton

    Texas Ton TS Member

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    If it goes away after it warms, just don't load it til it goes away and don't worry about it.
     
  10. cableguy

    cableguy TS Member

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    I wouldn't try the diesel fuel trick. While it works well in older engines, Bfalstang has a point. Newer engines have tighter tolerences. Take the truck to a COMPETENT GM dealer and have their lead driveability guy take a test drive. Chances are, he'll recomend swithcing to a stynthetic oil. Then get a second opinion just to make sure. I have a 94 Cevy p/u with 160,000 miles on it and run10w30 oil in it. I get 40psi oil pressure all the time even though it makes noise every time I start it.
     
  11. halfmile

    halfmile Well-Known Member

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    Castrol makes a flushing oil that is a safer method than the diesel fuel trick. You add the flushing oil and run then drain and refill with regular. I would do it on an old filter, not changing the filter till the flush is done.

    We used to idle them on Kerosene or Disel for a half hour then drain. NOT any more.


    HM
     
  12. AveragEd

    AveragEd Well-Known Member

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    Like many automakers, General Motors does not recommend 10w40 for any of their engines. In the 1970s and 1980s, poorly worded owner's manuals and 10w40 cost them a lot of money.

    For the 1975 model year, in the interest of encouraging oil conservation, GM went from publishing "recommended intervals" for oil changes of every three months or 3,000 miles to "maximum intervals" of six months or 7,500 miles with a filter every other time with a disclaimer (and here's where the wording problem came in), "unless you use your vehicle under severe operating conditions (see page xx)." Well, very few owners thought they used their vehicle "severely" and bothered to turn to page "xx" to find out that "severe" meant short trips, driving in heavy traffic and daily temperature swings exceeding 30 degrees as well as the expected dusty roads, steep grades, heavy loads and towing a trailer. Around here, those first three conditions are part of everyday life.

    Next, there is the good old American belief that if some is good, more is better. Applied to engine oil, it meant that if 10w30 is good, 10w40 is even better. But that's not accurate.

    Picture a quart bottle of 10-weight base stock. Now add an additive package to it that will give it the strength under friction and heat of 30-weight oil while retaining the flow qualities of 10-weight. Obviously, as you poured those additives in that bottle, some 10-weight base stock had to flow out to make room for the goodies - the bottle only holds one quart, right? Now, let's add even more goodies to make that 10-weight oil think it's 40-weight when the going gets tough and more oil comes out. Here's where the problem with 10w40 surfaces. Additives don't lubricate, OIL does and there's less of it left in the bottle of 10w40. Couple that with infrequent oil changes and you get two things - wear and sludge.

    In the early '80s, GM camshafts started failing at a pretty high rate on engines with 50,000 or more miles on them. The vehicles were out of warranty and GM would not pay for those repairs, so a consumer group got the Federal Trade Commission to order them to do so because the owners can't be at fault if they can't or didn't read their owners manuals completely. So we began replacing camshafts and lifters by what would turn out for some service departments to be the hundreds.

    Some service managers (and I was one of them) asked GM why we were installing the same part number camshaft as the "soft" ones that had failed if the same thing was only going to happen again. GM held a mandatory service managers' meeting in every area to educate us on the problem and after showing us a demonstration of 10w30 and 10w40, asked us to poll the owners of vehicles having camshaft replacements about their oil change habits and guaranteed us that in the majority of cases, we would find at least one of the following three things: they did not change their oil every three months or 3,000 miles, they used 10w40 and their engines would contain an excessive amount of sludge.

    Boy, were they ever right! Almost every owner defended his oil change interval by quoting the owner's manual but admitting they never bothered with page "xx." Probably 75% said they used 10w40 - it's better, right? And with one single exception, EVERY engine we took apart was heavily sludged. Some had the intake valleys filled to the bottom of the manifold with it. On one engine, the "Chevrolet" script stamped into the rocker covers was actually legible in the sludge under the covers!

    The moral of the story is change your oil according to your owner's manual and don't use 10w40. Since changing the wording in their manuals, GM has not had a similar "camshaft problem" (there have been one or two instances that involved coolant being allowed to contaminate the oil and damage camshafts) and those same part number camshafts are still available from your local dealership's parts department.

    I know a lot of motorcycle manufacturers recommend 10w40 in their engines. And they are high-revving engines, right? But now look at their oil change intervals and you'll find them to be much more frequent than those of cars. A couple of thousand miles at the most and some recommend changing as often as 600 miles! The same oil lubricates the engine and gearbox, so it has to have some added artificial "thickness" but they don't want it left in there very long.

    Some oils with a high "second number" are okay. For example, 15w40 is a great oil because of its strength under heat and friction loads and lubricates well because its 15-weight base stock doesn't require nearly as much of an additive package as 10-weight. It's the preferred oil of most diesel engine makers. And 20w50 is okay for the same reason, although today's engines might have problems with that stuff during cold starts, especially in sub-freezing temperatures.

    For what it's worth...

    Ed
     
  13. AveragEd

    AveragEd Well-Known Member

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    Some stories just take longer to tell, Pat. Trouble is, I've never found many that didn't!

    Ed
     
  14. CalvinMD

    CalvinMD Well-Known Member

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    I thought that the cold tap/knock was a infamous known trait of the Vortec engine...even named the Vortec Knock..most early Vortec did it forever from day 1
     
  15. AveragEd

    AveragEd Well-Known Member

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    Some GM engines exhibit mild piston slap on cold starts. It's harmless and lasts a maximum of 30 seconds - 10 seconds is much more common. It is the result of a slightly loose piston fit in an effort to lower friction in the engine. As the pistons warm, they expand to the desired size as opposed to fitting properly cold and becoming slightly tighter than necessary when hot.

    A knocking noise that sounds for all the world like a bearing knock on start-up is not abnormal on a lot of front-drive GM cars. It's actually coming from the transaxle oil pump and only lasts until the pump primes itself - about one second. You usually can't hear it with four-cylinder engines but it is noticeable in the cars with a V6.

    Ed
     
  16. AveragEd

    AveragEd Well-Known Member

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    Pat, as the president of a service and parts managers' club, I was treated to several trips to Detroit for tours of numerous GM facilities. I got to see some really eye-opening things like a brand-new Porsche 9-something Turbo being dismantled piece by piece for evaluation of designs that might find their way into the next generation Corvette. I saw trucks on a jig with a huge piston-like cylinder under each wheel that tried to literally shake the truck apart for days at a time. Another truck was in a room where the temperature could be varied from negative I-don't-know-what to positive a-hell-of-a-lot and back again in mere minutes to evaluate the clearances of everything from internal engine parts to plastic trim pieces and the adhesives that held them in place. You left wondering how anything could ever fail!

    Assembly plant tours were always my favorite and I used to put a Friday night bus trip together to the old Baltimore plant twice a year for our employees and customers. Seeing an entire exhaust system being completely fabricated from lengths of pipe and a muffler and be bent to shape and welded together in less than 20 seconds was amazing. Carpeting started as a flat piece and in what seemed like no time, it was cut by a stream of water the thickness of six-pound test monofilament fishing line and shaped by a huge "iron". I always wondered how they bled the braking systems on new cars because there is never a wrench mark or a spot of fluid on any of the fittings when they arrive at the dealership. They evacuate and charge the braking system just like an air conditioning system! I could go on but I've already had one long post today.

    American manufacturing technology is nothing short of amazing.

    Ed
     
  17. oz

    oz Active Member

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    Marvel mystery oil. add 1 quart (only) and just drive. this will clean a lifter. if it is piston slap the noise will still be there. Like the commercial, Like a Rock, put it in the ocean and leave it there. oz
     
  18. Bob in Georgia

    Bob in Georgia TS Member

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    I have a '99 Silverado 5.3L and I have also noticed some ticking when starting on cold mornings, but goes away within 20-30 seconds. Have been using Valvoline 10W-30 in her since the beginning. She's currently at 209,000 miles with original brakes and have over 103,000 on Michelin LTX tires. Now that I have written this
    the wheels will fall off tomorrow.

    Take care, Bob
     
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