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.
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.