Opalelement
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- May 2, 2014
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Hello guys,
Just found this forum about a week ago, been reading quite a bit on it so figured I would run an issue by you guys. I will try to be thorough, but I will also label sections so you can skip stuff you don't care about.
Background
I bought a one-owner 2004 Tahoe LT with 170k miles on a 5.3L in September 2012 after someone who doesn't understand what "Yield" means totaled my 300k mile 1997 Suburban. Only visible problem was the engine light with P0171/0174 and a dent in the front bumper (which was replaced by the used car dealer for free). I actually called the previous owner using a tire receipt from the glove box and asked them about the SUV and its history (because Carfax doesn't always tell everything); the woman said they traded it in a month before for a 2013 Silverado at her husband's request, if it was up to her she would still have it. She said the dent was from sliding into a trailer hitch when it was icy a few years prior, and the engine code had been there a while but never seemed to cause any problems. She also said that they had never had any problems with the vehicle overall. I believe her because she sounded authentic (and very surprised), she wasn't the one trying to sell it, and it had gone through three dealerships so I doubt the dealership and her were in cahoots.
Over the first month the temperature dropped from about 70 degrees to 40 degrees and it started being pretty erratic at idle; saw PIP3232B and replaced the intake manifold gaskets. Old ones looked like crap, replaced with heavier duty gaskets with a metal frame and thick black rubber (old 1, old 2, new).
Shortly after that, P0469 comes one and has been on since then. According to my research, my habit of overfilling my gas tank to round out the dollar amount killed the evap purge solenoid. Still haven't replaced it as from what I could tell it doesn't cause any real issue other than failing emissions inspections, which my state doesn't have.
The SUV doesn't have any modifications; everything is stock as far as I can tell. I would assume there were other repairs done by the previous owners if it reached 170k, but they still kept it the way they bought it.
The Current Problem
Since around January or February of 2013 the engine has had a slight knock. I don't think it is the infamous piston slap based on what I have read. Here are the details of the knock:
Since the knock started so soon after I got it, I don't think I caused it, but I definitely don't think I would have helped at all since then. Since I am not a car person I neglected a lot of maintenance (not that I ignored it, but that I never even think about it). I have done only one oil change using the $20 store-brand special at O'Reilly's in the year and 7 months I have had it and I am now at 200k miles (I think that oil change was about 9 months ago). I have never checked spark plugs or wires. I have checked fluid levels and added some oil and coolant when both were low, but that is about it.
Current plans
I plan to try to cover some of the long-overdue maintenance over the next few weeks to see if anything helps, but I don't know that it will. On this past weekend (by that I mean my weekend, which was Monday and Tuesday with my work schedule) I put a whole can of Amsoil Powerfoam through the intake and it runs and idles smoother, but the knock is still there (although it does sound a tad bit quieter - possibly a placebo effect). I planned on splitting a can of Seafoam between the oil and brake booster line tomorrow and changing the oil on Tuesday, this time using good quality oil (I plan on using whatever good quality is available locally for a few thousand miles as a sort of "refresher" and then switching to Amsoil XL or Signature Series and a new Amsoil filter to accommodate my non-maintenance schedule afterwards). I also plan to check the spark plugs at the same time.
Also I have been reading here and here that putting 1oz of 2-cycle marine oil per 5 gallons of gas seems to help keep the engine running smoother; has anyone had any personal experience with that? If so I would like to know what your results were.
End
I expect bad news and probably some hate for what I have done to this poor helpless vehicle, but I thought I would see what more knowledgeable people had to say first. Any comments or help you guys have would be appreciated.
Thanks,
Michael
Just found this forum about a week ago, been reading quite a bit on it so figured I would run an issue by you guys. I will try to be thorough, but I will also label sections so you can skip stuff you don't care about.
Background
I bought a one-owner 2004 Tahoe LT with 170k miles on a 5.3L in September 2012 after someone who doesn't understand what "Yield" means totaled my 300k mile 1997 Suburban. Only visible problem was the engine light with P0171/0174 and a dent in the front bumper (which was replaced by the used car dealer for free). I actually called the previous owner using a tire receipt from the glove box and asked them about the SUV and its history (because Carfax doesn't always tell everything); the woman said they traded it in a month before for a 2013 Silverado at her husband's request, if it was up to her she would still have it. She said the dent was from sliding into a trailer hitch when it was icy a few years prior, and the engine code had been there a while but never seemed to cause any problems. She also said that they had never had any problems with the vehicle overall. I believe her because she sounded authentic (and very surprised), she wasn't the one trying to sell it, and it had gone through three dealerships so I doubt the dealership and her were in cahoots.
Over the first month the temperature dropped from about 70 degrees to 40 degrees and it started being pretty erratic at idle; saw PIP3232B and replaced the intake manifold gaskets. Old ones looked like crap, replaced with heavier duty gaskets with a metal frame and thick black rubber (old 1, old 2, new).
Shortly after that, P0469 comes one and has been on since then. According to my research, my habit of overfilling my gas tank to round out the dollar amount killed the evap purge solenoid. Still haven't replaced it as from what I could tell it doesn't cause any real issue other than failing emissions inspections, which my state doesn't have.
The SUV doesn't have any modifications; everything is stock as far as I can tell. I would assume there were other repairs done by the previous owners if it reached 170k, but they still kept it the way they bought it.
The Current Problem
Since around January or February of 2013 the engine has had a slight knock. I don't think it is the infamous piston slap based on what I have read. Here are the details of the knock:
- It only shows up when the engine has warmed up for a while, and after it starts it slowly gets louder until it is fully at full temp.
- It happens on almost every drive that reaches full temp.
- It can appear and disappear during the same drive without restarting or cooling off the engine (one stoplight it is there, next stoplight gone).
- The pace of the knock speeds up along with RPMs when driving or revving, even when in neutral or park.
- It is fairly quiet from inside the vehicle.
- It doesn't go away with speed as far as I can tell (it is harder to hear at higher speeds because of road noise). I know for sure it can still be there at 50mph.
- It isn't affected by season, other than the engine taking longer to warm up in winter.
- There isn't any noticeable performance change when the knock is there versus when it is gone.
- No error codes have come on besides the ones mentioned above. Since P0496 is keeping the light on, I just check it every now and then using my bluetooth OBDII adapter.
- The knock sound comes from the passenger's side, and it seems like from the lower rear of the engine.
Since the knock started so soon after I got it, I don't think I caused it, but I definitely don't think I would have helped at all since then. Since I am not a car person I neglected a lot of maintenance (not that I ignored it, but that I never even think about it). I have done only one oil change using the $20 store-brand special at O'Reilly's in the year and 7 months I have had it and I am now at 200k miles (I think that oil change was about 9 months ago). I have never checked spark plugs or wires. I have checked fluid levels and added some oil and coolant when both were low, but that is about it.
Current plans
I plan to try to cover some of the long-overdue maintenance over the next few weeks to see if anything helps, but I don't know that it will. On this past weekend (by that I mean my weekend, which was Monday and Tuesday with my work schedule) I put a whole can of Amsoil Powerfoam through the intake and it runs and idles smoother, but the knock is still there (although it does sound a tad bit quieter - possibly a placebo effect). I planned on splitting a can of Seafoam between the oil and brake booster line tomorrow and changing the oil on Tuesday, this time using good quality oil (I plan on using whatever good quality is available locally for a few thousand miles as a sort of "refresher" and then switching to Amsoil XL or Signature Series and a new Amsoil filter to accommodate my non-maintenance schedule afterwards). I also plan to check the spark plugs at the same time.
Also I have been reading here and here that putting 1oz of 2-cycle marine oil per 5 gallons of gas seems to help keep the engine running smoother; has anyone had any personal experience with that? If so I would like to know what your results were.
End
I expect bad news and probably some hate for what I have done to this poor helpless vehicle, but I thought I would see what more knowledgeable people had to say first. Any comments or help you guys have would be appreciated.
Thanks,
Michael
