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6.0L Intake Gasket Leaking??

This is a discussion on 6.0L Intake Gasket Leaking?? within the Technical / Maintenance forums, part of the General Discussion category; My father has a 2003 Silverado 2500HD with the 6.0. Cold mornings when he starts it, it will have a ...

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    6.0L Intake Gasket Leaking??


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    My father has a 2003 Silverado 2500HD with the 6.0. Cold mornings when he starts it, it will have a very up and down idle. Very rough and sometimes will even die. It also leaks antifreeze now, appears to be coming from around the intake. Has anyone else had this same problem or know if a gasket replace is the answer? Also, is taking the intake off a do it yourself job or is it worth the mechanics bill?

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    Re: 6.0L Intake Gasket Leaking??

    Intake leaks are a very common problem on those engines, it isn't a very hard job to do just a little time consuming you just wanna take your time. If you don't have a maintenance book you will need one for all of the torque specs.

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    Re: 6.0L Intake Gasket Leaking??

    The antifreeze isn't coming from the intake on a 4.8,5.3 or a 6.0 because it doesn't flow through it.

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    Re: 6.0L Intake Gasket Leaking??

    I have seen probably about 10 6.0 liters losing coolant and it was the intake gasket, but when you said coolant doesn't run through the intake i checked with a couple of my friends and they all said they have coolant passages running through them, I could be wrong but that is what I thought.

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by Thunderbolt View Post
    The antifreeze isn't coming from the intake on a 4.8,5.3 or a 6.0 because it doesn't flow through it.
    The intake isn't hard to pull at all. I did it a few times on my truck and now getting ready to change them on my work truck for the same exact problem you're having. The only thing I would suggest doing is pulling the fuel rail and injectors so you can get the AIR line and purge soleniod(not sure if that's right. It's the thing right behind the throttle body) out of the way easier.

    While the intake is off you may also want to replace your rear knock sensor and harness. Then use silicone/RTV to seal up the sensor grommets and make a small dam around them to redirect any water that goes underneath the intake. This is something I plan to do on my work truck. Preventative Maintenance!
    Last edited by bigbob6988; 10-28-2009 at 06:14 PM.
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by Thunderbolt View Post
    The antifreeze isn't coming from the intake on a 4.8,5.3 or a 6.0 because it doesn't flow through it.
    +1

    Quote Originally Posted by rangermaniac View Post
    I have seen probably about 10 6.0 liters losing coolant and it was the intake gasket, but when you said coolant doesn't run through the intake i checked with a couple of my friends and they all said they have coolant passages running through them, I could be wrong but that is what I thought.


    Not on LS based motors. At the front of the motor there is a little tube that alows the coolant to flow from one head the to the other one. Those two fittings do have little gaskets under them and that could be where the coolant is comming from, or the coolant line that connects to the TB....
    Last edited by 1978steven; 10-28-2009 at 06:27 PM.
    2002 Silverado 2500HD LB7 CCSB LT
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    Re: 6.0L Intake Gasket Leaking??

    Wow some missinformation in this thread. No coolant through any LSX intake what so ever. 1978Steven is correct.

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by rangermaniac View Post
    I have seen probably about 10 6.0 liters losing coolant and it was the intake gasket, but when you said coolant doesn't run through the intake i checked with a couple of my friends and they all said they have coolant passages running through them, I could be wrong but that is what I thought.
    Welcome to 1999 and the GEN III engine...no coolant through the intake. Throttle body..yes. Intake...no.

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    Re: 6.0L Intake Gasket Leaking??

    Cool I guess you learn something new everyday I guess next time I take one apart I will pay more attention.

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    Re: 6.0L Intake Gasket Leaking??

    Thanks for the info....coolant leak was just the water pump, fan was just blowing it up to top front of motor. About an hour job, very simple to change out.

    Now about the intake still leaking....thats whats causing the rough morning idles....right....where do those leak? Pictures would help...down on the intake side of the heads....or up front behind the throttle control??

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    Re: 6.0L Intake Gasket Leaking??

    For the up and down idle it could be the IAC. My dad's 5.2 Dodge had a similar thing when cold, would stall. Replaced the IAC and solved the problem. I would look at the IAC before doing anything with the intake. I've never seen many posts here for the intake to leak on the 4.8/5.3/6.0.

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by skierZ71 View Post
    For the up and down idle it could be the IAC. My dad's 5.2 Dodge had a similar thing when cold, would stall. Replaced the IAC and solved the problem. I would look at the IAC before doing anything with the intake. I've never seen many posts here for the intake to leak on the 4.8/5.3/6.0.
    +1....

    You'd have a CEL if your intake was leaking, that's a pretty decent vacuum leak.

    Pull the intake tube off the tb, could just need to be cleaned up in there. It's pretty typical for the tb's on the LS motors to get gunked up with deposits and such. A good tb cleaner like Sea Foam's Deep Creep work great at breaking down the gunk and getting deep into the passages in the tb to clean out the gunk. I clean mine out every oil change as part of preventative maintenance, it only takes a few extra minutes to do....
    2002 Silverado 2500HD LB7 CCSB LT
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    Re: 6.0L Intake Gasket Leaking??

    Do not change the IAC valve yet! It's too expensive and it doesn't fail nearly as often as the intake gaskets do. Just clean the throttle body and valve and everything. If that doesn't fix the problem then you're right back at the intake gaskets, which are cheaper but harder to replace than the IAC valve.

    My '00 work truck has the same problem and it hasn't thrown a code yet. Last year when it was doing it I also swapped throttle bodies with my '99 and it made no difference at all. Then I swapped just about every sensor on the engine with my '99 and still no difference.

    Oh, and lastly does it idle up and down on warm/hot mornings?
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Re: 6.0L Intake Gasket Leaking??

    Have you guys tried spraying starter fluid around the intake runners to see if the intake gasket is for sure leaking. If it is leaking the vacuum will suck in the starter fluid and the engine will rev. The intake gasket is not hard to change, just time consuming....
    2002 Silverado 2500HD LB7 CCSB LT
    EFI Live by Rob at ATP, Edge CTS Insight DSP 5 control, S&B CAI, PPE boost valve, Pro Fab AIH, AirDog II 165, PPE WIF sensor delete plug, 5" stainless exhaust, Cognito braces & HD tie rods, H2's 315/70 R17 BFG's
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    Re: 6.0L Intake Gasket Leaking??

    The idle just seems to be crazy when its cold outside. My guess is the different contraction rates of the aluminum to composite materials. Just a guess on my part. The TB is visibly dirty, it almost looks like it has sucked oil in from somewhere. I looked at it when i had everything off from the front when changing the water pump. Going to try the starting fluid tonight, thanks.

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by ThomasC View Post
    The idle just seems to be crazy when its cold outside. My guess is the different contraction rates of the aluminum to composite materials. Just a guess on my part.
    That's it! In this real cold weather everything shrinks creating gaps large enough to cause the idle problems. Once everything begins to warm up the gaps close up and the problem is gone. The vacuum leak doesn't stick around long enough for the PCM to detect it and throw a code.
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Re: 6.0L Intake Gasket Leaking??

    Quote Originally Posted by bigbob6988 View Post
    That's it! In this real cold weather everything shrinks creating gaps large enough to cause the idle problems. Once everything begins to warm up the gaps close up and the problem is gone. The vacuum leak doesn't stick around long enough for the PCM to detect it and throw a code.
    I have the CEL indicating an intake leak. Pretty sure its the intake. Rough estimate on how much a shop would charge to do it?

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    Re: 6.0L Intake Gasket Leaking??

    I don't know much about shop rates, but I wouldn't let them charge more than two hours of labor. It can actually be done in less than an hour...
    99 Silverado ECSB 4X4, LQ4, Patriot Stg. 2 243's w/ 59cc chambers, TR224-112, Pacesetter LT's, Nelson tune, FLT Lvl 5.5, PI 3400, UD pulley, 160* t-stat, E-fans, 6'' Fabtech lift, 3'' body lift, 37'' XTerrains, 4.56's, 4'' shackle flip 13.3 @ 99mph on 37's or 13.0 @ 101mph on 31's

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    Re: 6.0L Intake Gasket Leaking??

    It can be done in 30mins, if you know what your doing.

    2500 6.0 vortec 6in skyjacker lift with keys on 16in eagle wrapped in good year kevlar 285, LPP LT's, gmpp cam, efi live tuning software, true dual flowmaster 40 series Circle D 2500-2800.

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    Re: 6.0L Intake Gasket Leaking??

    Hate bringing up an old post but I guess we'll just have to live with it ....

    One of my work vans, a 2004 2500 GMC with the 6.0 is still loosing coolant supposedly. We changed out the water pump and such and it hasn't overheated but still has a "shake" to it. We checked compression and all 8 cylinders come out just fine. Since LS engines have a dry intake how bout the TB losing coolant? We were thinking of just bypassing the tb with a barbed fitting and some gear clamps ( same as on my 99 Z28 ) . Any ideas fellas as for the shaking?

 

 

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