Trailblazer 2.8 LTZ - funny noise





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  1. #1
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    Default Trailblazer 2.8 LTZ - funny noise

    Just after the turbo replacement end last year, I once heard a funny noise, sounded like a flat tyre (something like woepf woepf () ) but as I said that was only once. Now during December driving with a loaded car and caravan hitched, doing an incline, I again heard it, but more constant every time going up a hill and the auto box kicks back to a lower gear. Very difficult to explain toe sound and to simulate it. Going for several test drives with the service manager and service personnel, the sound not there. This worries me a bit as the warranty expires in Feb and if it is a warranty item, if anything is at fault, I want it sorted, and for peace of mind as well. Problem is what do you fix if you do not know what to fix!!

    Anybody had the same or similar?
    Uys Snyders

    Trailblazer 2.8DuraMax
    Bushlapa Vlooi B237

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    It could be the waste gate, but get it checked by a dealer
    2013 Chev Trailblazer 2.8 4x4 auto.

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Dealer cannot find anything. Going back this week and will carry on until solved!!

    Sorry for stupid question - what is the waste gate?
    Uys Snyders

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Waste gate/dump valve is a valve that releases excess pressure from the turbo when changing rpm, such as changing up gears from a lower gear that was at high revs. Turbo can't slow down like the engine rpm can, so pressure has to go somewhere and gets dumped.

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Now my turn for a dumb question.
    Is a VG turbo fitted with a waste gate?
    I was under the impression that the veins adjust according to "need" under electronic input. The exhaust gas not required for boost, is simply allowed to bypass and to go down the exhaust.

    That said; your symptoms do seem to mimic wate gate type dump. It makes me wonder if the Variable Geometry is funcioning correctly.

    1) do you know for a fact that a brand new complete (including that little electric motor that operates the VG) turbo was fitted?
    2) don't you have a 12 month warranty on the new turbo?

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    I have just spent a few minutes on Google and YouTube. I recommend you do the same, there is lots of usefull info there.

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Quote Originally Posted by Gav.S View Post
    Waste gate/dump valve is a valve that releases excess pressure from the turbo when changing rpm, such as changing up gears from a lower gear that was at high revs. Turbo can't slow down like the engine rpm can, so pressure has to go somewhere and gets dumped.
    Thanks Gav
    Uys Snyders

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Quote Originally Posted by RoelfleRoux View Post
    I have just spent a few minutes on Google and YouTube. I recommend you do the same, there is lots of usefull info there.
    Thanks Roelf - surely I will do.
    Uys Snyders

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Quote Originally Posted by RoelfleRoux View Post
    Now my turn for a dumb question.
    Is a VG turbo fitted with a waste gate?
    I was under the impression that the veins adjust according to "need" under electronic input. The exhaust gas not required for boost, is simply allowed to bypass and to go down the exhaust.

    That said; your symptoms do seem to mimic wate gate type dump. It makes me wonder if the Variable Geometry is funcioning correctly.

    1) do you know for a fact that a brand new complete (including that little electric motor that operates the VG) turbo was fitted?
    2) don't you have a 12 month warranty on the new turbo?
    Roelf I can only say what was said to me.
    1) Brand new turbo from factory - that set me back 4 days in my holiday planning
    2) again was not informed if it was a partial or full replace. Saying that, I was told it is a full turbo replacement - my understanding is that it will be the complete unit.

    Unfortunately I left in a hurry and have not received any paperwork - promised it will send to me. Have not received it and have not followed up on it . My view was it should be logged on the system of GM!

    Maybe worth a try and contact the dealer in Bloem and try to get the promised paperwork!!
    Uys Snyders

    Trailblazer 2.8DuraMax
    Bushlapa Vlooi B237

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    I would suggest you get the techs to start with the plumbing on the high pressure side of the turbo. Maybe a poorly fitted clamp or a pipe that got damaged during the turbo replacement.

    Google suggests that max boost can get as high as 40psi, I think that is almost 3bar. That will find any defect in the plumbing and most likely loudly complain as some of the air escapes.

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    Default Trailblazer 2.8 LTZ - funny noise

    Roelf thanks for taking the trouble to make suggestions - really do appreciate. I spoke to the dealership this morning and we will tackle the issue together. Only problem is, warranty expires on 8 Feb and I am leaving for Swakopmund on the 9th

    He also confirmed that they did a full and thorough inspection of everything coupled to turbo replacement.

    I am just hoping that it is something small.
    Last edited by Uys Snyders; 2018/01/30 at 07:34 PM.
    Uys Snyders

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    J..... that is tight timing, but I really do believe that any legitimate issue that surfaces before the warranty expires, should be covered if solving it goes over that date. I suppose Chev's commitment will become apparent now. Sorry that you have to be the guinea pig

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Ja Roelf ek hopp ook so. Ek het darem ook die versekering van die diensbestuurder gekry hulle sal alles in hul vermoe doen om die waarborg te eerbiedig, al word die oplossing na die 8ste gekry.
    Ek sou regtig dink dat die waarborg verstryk aan die einde van die maand waarin die voertuig gekoop is en nie OP die datum nie.
    Kom ons hou duime vas en sien wat gebeur.
    Uys Snyders

    Trailblazer 2.8DuraMax
    Bushlapa Vlooi B237

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Maybe hook up a loaded trailer and drive up a few hills, if the sound comes back out the woodwork drive straight to the dealer and have them join you for a ride.

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    Default Trailblazer 2.8 LTZ - funny noise

    Just quick feedback - went to the dealer this morning with the caravan hitched. Was successful to replicate the noise. Car is going in on Monday. Lets wait for the feedback after repair. Will report and post when I know more.

    I was given the assurance it is NOT the turbo, inside the engine or gearbox. So what is left - drive shaft bearings? This only occurs between 40 and 70 km/ph
    Last edited by Uys Snyders; 2018/02/02 at 08:33 PM.
    Uys Snyders

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    Default Re: Trailblazer 2.8 LTZ - funny noise

    Hi Uys,

    Wat was toe die uiteinde?
    2014 Chevrolet Trailblazer 2.8 Auto 4x4
    2015 Jurgens XT140 Ext... maar ek soek 'n Bush Lapa
    Who needs a diff lock if you have 500Nm's

  17. #17
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    Default Trailblazer 2.8 LTZ - funny noise

    Eintlik nog geen uitslag!
    Dinsdag by die handelaar gekom net om uit te vind die hele dorp se krag is af en verwagting is dat dit vir minstins 48 uur gaan af wees!!!
    Hulle het my die versekering gegee daar is niks met die turbo, ratkas of enjin fout nie, maar wel iets (baffle of iets dergliks) los in die uitlaatpyp! So is ek na n volgende handelaar in Kaapstad wat aan waarborg Chevs mag werk, net om min of meer dieselfde storie te hoor. My tyd was baie min aangesien ek op 9 Feb Namibie toe vertrek het. Was baie bekommerd maar wat kan mens s??
    So is ek daar weg en veilig in Swakop aangekom, geen issues op die pad opgetel nie. Is die geluid nog daar? - ja beslis hoor ek dit van tyd tot tyd.
    Ek sal maar as ek terug in die Kaap is die saak weer verder vat!!
    Ek vertrou die terugrit sal net so voorspoedig wees soos die rit na Swakop!
    Last edited by Uys Snyders; 2018/02/12 at 10:58 PM.
    Uys Snyders

    Trailblazer 2.8DuraMax
    Bushlapa Vlooi B237

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