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Chevy Silverado Problems



  • wight1wight1 Posts: 218
    I had the engine top soak done on my 2000 6.0l about a month ago. The knock went away immediately, but its back again after only about 1000 miles. I've read other people have had the same results with the engine soak, so I'm not sure its worth it. Mine's been knocking for about 20,000 miles now and nothing has blown up yet, but don't know what the long term effect will be.
  • sf0383sf0383 Posts: 204
    Thanks for the input. I think I will wait it out for a little while and see if they come up with a fix instead of a patch. I frankly don't trust a dealer service department to change the spark plugs without screwing it up.
  • obyoneobyone Posts: 8,054
    The result of waiting could be the tips of the plugs falling off, never to be found again.


    Usually the isolator noise will go away on rainy days as the water and humidity lubricates it. When fair weather returns, so does the isolator noise. That knock noise you got is not a good one. It is related to excessive clearance in the main bearings. No one knows the long term effects of it, but I would think it will only get worse as the clearance increases over time.
  • pilot9999pilot9999 Posts: 7
    Let me know if you find anything. I live in
    Lake Havasu, AZ where it is never below 90 degrees
    so I can't comment on the temperature connection.
    Passing trucks on the freeway sometimes affected
    it but not always.
    Tom K
  • wight1wight1 Posts: 218
    I think you have confirmed my suspicion about the coil spring noise. I noticed the noise is not there on rainy days. I did spray some of the famous Permatex silicone lube up in there, but that didn't seem to make any difference - maybe I should try some Lubriplate - LOL!

    I don't know about the engine knock. It sounds like a bottom end noise (rod or main bearings) but many folks say its the carbon build up problem in the cylinders. If it were the rod or main bearings, how does the application of GM Top Engine Cleaner for carbon deposits make the noise go away?
  • redsilveradoredsilverado Posts: 1,000
    i went as far as pulling the clip that retains the pivot on the hinge in place and lifting the rear door high enough off the hinge pin to squeeze some silicone grease in there. then a small amount of grease on the latches. after that i wiped the weatherstripping with the same grease (biggest effect) to finally eliminate sqeaking and creaking. since i upgraded the stereo, i invested in the soundproofing material known as "dynamatt" and applied it to the door outerskin and inside metal frame. then i stuffed foam in and around the keepers of the interior door panel.
  • obyoneobyone Posts: 8,054
    Regarding the top cleaner...that's a good question. I don't have the answer to that one only as a cause and effect. The top cleaner provides temporary relief from the knock but returns as carbon builds up. It may be a relation between the two. I would have to research this. Could you tell me what the purpose of the top cleaner, exactly what is it supposed to clean?
  • toortoor Posts: 38
    That sound that I thought was from the nerf bars, and now I confirm is not.........
    well, today when i took my truck out I noticed that it occurs mainly when going around curves or over bumps at slow speeds or even when braking.
    Does this mean anything?? I guess it's when the frame is in a flex position.
    Sceduled to take the truck in on Wednesday. Hopefully the techs can figure out what the hell it is that is causing that noise.
    Anyone want to take a guess?
  • wight1wight1 Posts: 218
    the GM Top Engine Cleaner product has been around for years. Its a cleaner made exclusively for removal of carbon deposits on the piston crowns and the cylinder heads. A couple of independent garages in my area even say its the best they have found for cleaning up combustion chamber deposits - one time years ago when I had my wife's Olds in for a tune-up and carb overhaul (yes, that long ago) at a local garage, the guy said he wanted to use the GM cleaner because the carb had been so bad out of adjustment, it was dumping a ton of fuel in there.

    When I recently got my truck back from the dealer last month after the carbon removal, I noticed an odor from the exhaust which they said was just some of the residual cleaner being burned off - the odor went away the following day. Interestingly, the smell was exactly the same odor I noticed when I used OMC Engine Cleaner to remove the carbon deposits in my outboard motor. That stuff really worked too - you sprayed it in the carbs and let it soak for a few hours. When you start it back up, it belches clouds of white smoke for awhile which really stinks and the carbon comes pouring out the prop exhaust. I was wondering if OMC just borrowed GM's formula or vice versa!

    sounds like a frame flex problem, maybe loose bed mount bolts or bad mount rubber bushings.
  • rayt2rayt2 Posts: 1,208
    Obyone, it's designed to clean abnormal carbon deposits from pistons/heads, how our new engines are getting all this carbon (as the dealers assume) is beyond me. My 5.3 also knocks but only on start up and as soon as the oil is flowing it's gone. I feel it's coming from the lower end. I'm no genius but 35 years of working on vehicles is telling me I have to much clearance/tolerance on either the piston wrist pins or more than likely the rod end bearings. GM itself has stated that they tightened up the clearance on the newer engines for 2001 so who knows what long term affect will be, hopefully enough complaints will be recieved by NHTSA to warrant GM to give extended warranties to those with the problem or replace your engine (don't hold your breath on that one now). My 2c.

    Ray T.
  • redsilveradoredsilverado Posts: 1,000
    we're in the same boat when it comes to this mysterious noise. mine only happens at very low speeds and like you said, when the frame seems to be in a flex.
  • redsilveradoredsilverado Posts: 1,000
    how many of you hear a snap/pop sound when startin up your 5.3L?
  • ryanbabryanbab Posts: 7,240
    only when i eat rice krispies do i hear snap krackle and pop
  • ricschricsch Posts: 540
    Anyone experience any trouble with the passlock security system on their truck? I just had my remote starter disconnected from it to verify if it's the factory security or the remote start. The guys at the audio shop say they've found it to be the factory system in 3 other gm vehicles.
  • obyoneobyone Posts: 8,054
    Rememeber reading something about that in the manual. Includes the radio. Not too sure but the radio's been removed.


    I remember using that stuff on my '64 Galaxie 500, remember that one? Belches of white smoke that smelled like cr*p. I think GM has come out with it as a temp fix and hopefully you won't return to the dealer. I agree with Ray on this one on the rod end bearings. Since I play my stereo loud, can't hear it on start up or at idle. However, when I get out of the truck, I can hear the knocking at idle. I have a 6/100K bumper to bumper so I haven't been too concerned.

    Have an appointment to fix my seat cushion for the third time next Tuesday so I can ask at the same time. BTW, being the third time for the seat cushion could I qualify for lemon law? hehe The cushion bulges after awhile. I can believe if it sunk from the weight but the opposite is happening.

    snap, crackle? first I heard of that. Now as ryan said, I'd get concerned if you hear all three of them...snap, crackle, and pop. lol
  • obyoneobyone Posts: 8,054
    Bulletin No.: 99-08-64-016

    Date: September, 1999


    Use of Silicone for Weatherstrip Maintenance

    2000 and Prior Passenger Cars and Trucks

    In the past, questions have been raised regarding the proper care and maintenance of weatherstrips. The purpose of this bulletin is to clarify which materials are recommended for use when required.

    Periodically, a thin coating of silicone grease can prolong the life of the weatherstrip. The silicone will reduce wear in the contact areas as well as reduce squeaking and sticking conditions. During very cold or damp weather, more frequent applications may be necessary.

    Important: Be careful in areas where clothing may come in contact with the weatherstrips as silicone or dirt may be transferred to clothing.

    Parts Information
    Parts are currently available from GMSPO.
  • obyoneobyone Posts: 8,054
    Engine Noise
    Bulletin No.:

    File In Section:
    06 - Engine/Propulsion System

    February, 2000

    Engine Noise (Check/Replace Crankshaft Position Sensor)

    1999 Chevrolet and GMC C/K Models (Silverado and Sierra) with 4.8 L or 5.3 L V8 Engine (VINs V, T -RPOs LR4, LM7) Built within the VIN breakpoints shown in image.

    Some customers may comment on a whirling sound from the lower rear side of the engine. This occurs as the engine warms up, between 1500 and 2000 engine RPM. The sound may not be present on a cold engine.


    The crankshaft position sensor may be making contact with the reluctor ring.


    IMPORTANT: Dealers may encounter a few vehicles, shipped from the vehicle assembly plants, which have a 2nd rubber 0-ring installed over the crankshaft position sensor, and a copper shim under the mounting tab.

    1. Remove the crankshaft position sensor (1), and check for witness marks caused by contact with the reluctor ring. Reference the Service Manual procedure as needed.

    2. If no witness marks are evident on the crankshaft position sensor (1):

    IMPORTANT: Do not place an additional shim washer (2) on the crankshaft position sensor (1), if one was not previously installed.

    2.1. Reinstall the original crankshaft position sensor (1) with any 0-rings and shims that may have been previously installed.


    Tighten the mounting bolt (4) to 25 Nm (18 lb ft).

    2.2. Continue with standard diagnostic procedures.

    3. If witness marks are evident on the crankshaft position sensor (1):

    ^ If a shim washer and/or 0-ring had been previously installed: call Technical Assistance for additional instructions

    ^ If a shim washer and/or 0-ring is not present:

    3.1. Place a shim washer (2) P/N 12565102 on a new crankshaft position sensor.

    3.2. Install the new crankshaft position sensor (1) with the mounting bolt (4).


    Tighten the mounting bolt to 25 N.m (18 lb ft).

    3.3. Perform the Crank Angle Sensing Error (CASE) re-learn procedure.

    3.4. With the engine at operating temperature, verify the correction of the noise condition.

    Parts Information

    Parts are currently available from GMSPO.
    Warranty Information

    For vehicles repaired under warranty, use chart.
  • valkyvalky Posts: 21
    Could it be that the carbon build-up in the cylinders is increasing the compression ratio, thereby, putting more pressure on the rod bearings?

    Is it feasible that when they do the top engine clean that it takes the cylinders back to a stock ratio, thereby, reducing or eliminating the knock?

    Just a couple of questions I've kicked around.

  • toortoor Posts: 38
    Well my westin spacers just arrived.
    Came in a normal envelope. I was like, what is this?

    They are definately not what I expected. But if they do the job!
    There are 4- 1mm thick round plastic spacers.
    Same size as the rubber cab mounts. you just put them inbetween the step bracket and the cab mount I guess.
  • ricschricsch Posts: 540
    I believe Theftlock is for the radio, passlock is for the security system. Evidently to do with sensing the correct key in the ignition-funny the key looks like an ordinary key.
  • obyoneobyone Posts: 8,054
    A little secret. I had a key made a Home Depot using the old style C/K key. What happens when I use this spare key is that the rado starts up and runs normally. So much for the coded key. Now if someone used a screwdriver...well that might be a different story.
  • rayt2rayt2 Posts: 1,208
    Obyone.......You sure your not the test marketer for GM? you come up with the weirdest problems, you must be kin to those crash test dummies only you get to try out the trucks before they crash'em, haha. I'd say a seat spring has dislodged from it's place thus causing the "bulge" and if you qualified for "lemon law" on that one I'd say the arbitrator has been puffin on that Maui Waui to long LOL. Home Depot replacement key starting the Rado??, so much for that computer chip in our key rings to prevent theft!
    As for the engine knock were there any TSB's issued for that or did they just issue you the extended warranty to shut you up hoping you'd go away? Boy were they mistaken!LOL

    Ray T.
  • obyoneobyone Posts: 8,054
    Not sure what they did the last two times on the seat. All I know is that it went in with the material lifting on the seat and they returned it with the seat as flat as a pancake. Like they steamed it or something to make the material shrink. I guess they gave up and will be sending to upholtery shop.

    They are also stumped on the child safety harness as I wanted one. GM sent two harnesses which both don't fit. So now they are looking for one that matches the picture in my service manual.

    There are no TSB's for the knocking sound. Maybe if enough customers complain...they'd be forced to issue one.
  • hunter48hunter48 Posts: 30
    When starting it sounds like lifters knocking like the oil pump lost its prime, and when you get above 2300 rpm it sounds like piston slap, truck has 12,000 on it, GM said thats normal I don't think so. If it weren't for the gas engine sounding like a diesel it would be a geat truck!!
  • jrpkcjrpkc Posts: 3
    Anyone experiencing a piter-patter type rattle coming from the Captains Chair Style passenger seat? Can't seam to locate source?
  • abc246abc246 Posts: 305
    The key is not coded on newer GMs, the smarts are in the key cylinder. There are hall effect sensors that put out a code read from the high and low spots on the key, sort of like the mechnical key locks. The computer knows what the code should be.

    The neat thing about this system is that you can use normal keys. It is a great idea, more so if you ever had to buy a $100 dollar key!
  • valkyvalky Posts: 21

    I had this noise. What I found was the metal part on the seat belt buckle on the passenger side rattling against the plastic button. I just moved the buckle down over the button and the noise was gone. I hope this is it. Good luck

  • redsilveradoredsilverado Posts: 1,000
    thanks for the TSB. i knew there was one, but haven't seen it since the link at ryan's site died. at least now, i'm down to a faint "dink donk" sound in the rear.
    on the snap/pop sound that the engine makes sometimes, it reminds me of our '68 olds Delta 88 that had a high compression 455. it always had that snap sound when firing up. engine ran well into the 100,000's without using so much as a 1/4 of a quart of oil between changes. on my 5.3 the oil pressure always stays above 50 psi at idle and higher at highway speeds, so i'm not gonna worry about it.
  • ryanbabryanbab Posts: 7,240
    theres a new site.

    Ill email you tonight when i get home ok

This discussion has been closed.