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VT 3.8 Inlet Manifold Gasket Replacement - recommendations?

Discussion in 'VT - VX Holden Commodore (1997 - 2002)' started by vtbob, Apr 12, 2009.

  1. vtbob

    vtbob New Member

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    I'm in the slow process of replacing the inlet manifold gaskets on my VT 3.8.

    Are there any recommendations, such as putting sealant on the gaskets etc?

    Noticed the end pieces had some black silicon on them - Is that a factory thing?
    I bought the car ar 80k and it is now at 200k+.
    Not been touched by me previously!

    Anything else worth replacing or doing?

    Noticed the valley is a pain to clean without dropping crap into the working!

    Just going to have to do an early oil, filter & coolant replacement.

    BTW, What is a good coolant to use?
    Been using some $20 ready mixed stuff, but have noticed some corrosion around one of the coolant ports on the manifold, so maybe it just aint good enough.
     
  2. Raging Bull

    Raging Bull New Member

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    Yeah silicon is a must when putting on the red side rubber seals, you put the silicon on the side corners and yeah I'm pretty sure it is a factory thing since there was silicon when I took my ones apart.

    As soon as you remove the injectors plug up the holes tight with some tissue pieces just don't plug them in too deep just enough to cover them so that you can easily take them out later. Once the manifold is removed get a big rag, preferably some kind of an old t-shirt and place it on top of the area so that no crap can get in there whilst you clean the place out.

    Careful taking the manifold out once the screws are undone.

    - There's an annoying bracket at the back of the manifold holding it in place, try to pry it back while taking the manifold out.

    - Don't forget to disconnect everything before pulling it out, I forgot about the coolant temp sensor connector located on the passenger side edge of the manifold.

    - Try not to damange any of the vacuume hoses that you have to disconnect when taking the thing apart.

    - Theres a metal o ring at the front of the manifold(might be only on L67) if you damage it and put it back together again it will leak, so be careful when taking it out again.

    - Give the manifold a nice clean once it's off and make sure to remove all the old gaskets etc from the top and bottom and if you have access to some sand paper, give it a good clean so it's nice and shiny and adheres to the new gaskets nicely. Buy some throttle/carby cleaner and go crazy with it.

    - Use a torque wrench when torquing the manifold screws, make sure you get the correct torque. From memory it was only a weak 30Nm for the manifold.

    - Clean out the throttle body, IAC and manifold with the throttle body cleaner, if your manifold is super grimy and black go to Safeway and pick up a bottle of Mr. Muscle oven cleaner for $3 it will take away the grime and bring back the original shine in no time.

    - As you put the new gaskets in and bolt up the manifold, put the heater on hot and undo the bottom radiator hose, then get your garden hose and flush out the system through the top, wait until clean water is coming out from the bottom. Do the same thing by disconnecting the heater hose and forcing water through there until it's clean on the other end.

    - Change the thermostat/gasket as well while you're at it, takes only a few minutes.

    - Pick up the genuine Holden coolant concentrate and mix it with distilled/demineralised water. You'll fit about 5 litres of concentrate in the radiator and the rest has to be filled up with the water as you're bleeding the system and freeing up the air gaps.
     
  3. vtbob

    vtbob New Member

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    Thanks for all that info.
    Only problem I already have it off so missed out on your initial tips.:)
    Think I will have to get the vacuum cleaner on it to suck out any bits that have fell in.
    I will have to try the oven cleaner because everything else I have tried, including carby cleaner didn't remove much of the grime.
    Is it worth replacing injectors that have done over 200k?
    The engine was running just fine prior to the strip.

    Thanks again!
     
  4. Raging Bull

    Raging Bull New Member

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    Yeah get your injectors supersonic/overhauled cleaned or whatever it's called, it's worth it in my opinion. Mr. Muscle will smash the grime away and bring it back to the aluminum, it's a great product. Don't forget to bleed the cooling system properly.
     
  5. vtbob

    vtbob New Member

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    Job now done, Mr Muscle worked a treat.

    Couple of tips.

    Keep your valley end gasket pieces incase the ones you get in the kit are different.
    The ones in the kit I had wouldn't fit at all!
    Different profile!


    Although you dont have to touch the throttle cable adjustment, be careful when tightening the 2 lock nuts. Mine were loose, and on tightening they easily sheared the outer sleeve.
    A few cable ties fixed the problem.:whistling

    As recommended, change your thermostat. Mine looked as grotty as hell!
     
  6. Simonn

    Simonn New Member

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    sorry. But I suspect my car may have a leaking intake manifold gasket. If I was to put a radiator pressure testor onto the radiaor would it show a drop if the intake manifold gasket is leaking? if it does not show a drop would it mean 99% that my gasket is not buggered?
     
  7. alien

    alien New Member

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    Simonn, if you have a pressure tester then yes thta's the best way. Or you could check your oil for a milky appearance. In the sump and under the filler cap [or if you want remove the rocker covers and look too].
     
  8. Simonn

    Simonn New Member

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    ok thanks would you happen to know what pressure to pump it up to? btw its on a vx 3.8
     
  9. alien

    alien New Member

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    120-150kPa is the norm.
     
  10. Simonn

    Simonn New Member

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    thanks. Anyone know how likley it is for vx engines to do head gaskets. The old man done a c02 test from the radiator and it gave a positive read which means exhuast gases are getting into the coolant somewhere. I'm praying it not from the head gasket.
    I was thinking maybe there is a leak between the comustion chamber and coolant gallerys in the intake manifold with the engine having an EGR type system there may be a small amount of exhuast gasses in the combustion gasses and becuase of a possible leak between the combustion intake and coolant galleries some of the combustion gasses (with the exhuast gases in them from the EGR) may be getting into the coolant thus giving a positive reading. If anyone could commant on weather or not this is possible it would be great.
     
  11. vxcalais_01

    vxcalais_01 Active Member

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    Could still be a inlet gasket though, heads is only 8 bolts away on each from doing the valley gasket, so not hard once you get to that stage. just change it anyway, you will know as you go, you will see where the gasket has blown, if not, check the heads. My symptoms were oil in the radiator. Exhaust gases could bleed in to the coolant from the inlet gasket possible......?
     
  12. Simonn

    Simonn New Member

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    thanks we replaced the oil today. there were no signs of water in it which is good. We also flushed out the radiaor which was really brown and sludgy. This could possibly be becuase of the holden tablets that holden uses (car has been serviced at holden it whole life) topped it up with fresh stuff and will see how it goes now.
     
  13. Simonn

    Simonn New Member

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    ok I have driven the car problaby 50kms in total since radiaor flushing. I have checked coolant level and it has dropped a few cm's below filler cap. We put a pressure tester onto it pumped it up to 140kpa and no drop what so ever. If the inlet manfold gasket was leaking sureley it would come up on the pressure tester wouldent it?. We are thinking it may be a faulty radiator cap. So will try a new one in the next few days and keep you posted. Read somewhere that there is a step by step manifold gasket replacement on the net somewhere. If anyone knows could you please PM it to me. I want to get familiar with whats involved just incase it turn out it need changing.

    thankyou
     
  14. mlinton74

    mlinton74 New Member

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    After market Radiator caps a big no no

    One strong tip I must stress.... please do not buy after market radiator caps for your VT Commodore!!! They are built differently to the genuine article and will leak water when motor is warming up.

    Do yourself a favour and buy a genuine cap.... I learnt the hard way!!!
     
  15. Room42

    Room42 New Member

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    mate it cost $50 for an intake manifold gasket set. $15 for the silicone for the corners. Swap it and be done. It wouldn't be far from stuffed anyway if it aint, but it sounds like it is.
     
  16. purekiwi

    purekiwi New Member

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    i got a radiator cap from repco a month or so ago and it seems to be fine
     
  17. MaverickAus

    MaverickAus New Member

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    Where did you get the gasket set for $50?
     
  18. darcycammo

    darcycammo Member

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    Did have VS Berlina now have VT Berlina
    i got the gasket set for $52 at R&E Auto in Pakenham Vic
     
  19. nadeemrajabali

    nadeemrajabali New Member

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    Electric Fault after Changing Inlet Manifold Gasket

    Thanks, I did my manifold gasket and everthing went Ok,

    Now when I drive my car for 7 to 9 Kilometer, electric fault light shows up, and if I switch off the engine and re-start it instantly it goes off and appears again after 3 to 4 kilometer.

    can anyone help me please, if with some picture.
     
  20. Full Spectrum

    Full Spectrum Bro it's a VW your Audi!

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    Go the MACE gasket. And anything else you need get from holden as they dont sell it as a kit they only sell them individually so its not that bad.
     

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