I have a 1991 3.1L pontiac firebird that's been overheating and loosing coolent. Turns out the silicone part of the manifold part is shot and shooting liquid from the front. I don't really have that much experience working on cars but i am going to try and replace the gaskets/silicone seal myself. I have two manuals im going from but neither have a 3.1L repair part in it for the mnaifold. Would it be best to go follow the 2.8L or the 3.4L directions?. Also Since im replacing the gaskets do i need to replace the valve cover ones aswell? Ive also seen guys removing their alternators to replace the gaskets, but have heard from my brothers who's more experienced that we wouldn't need to remove it, want to get our guys opinion. One last thing, im a little confused as where to start, so anyone willing to give me a quick rundown would be much obliged.

 

What is this silicone part that you are talking about? Yes, the 2.8 should be exactly the same as the 3.1 and I would just take the alternator off just to give you some more room. I am sure you don't have to but it would be nice. If you are taking apart the engine to replace the intake manifold to heads gasket I would:

1. Take off the upper plenum. all 10 mm bolts, make sure not to break them.

2. disconnect throttle cable/tv cable and cruise control from the throttle body.

3. remove the bracket that holds the cables from the middle intake manifold. two 10 mm bolts. one on the upper plenum i think and one on the middle intake manifold

4. disconnect fuel rail and injectors from lower intake manifold. You might have to disconnect the fuel lines from the fuel rail to make it easier to move around but you also might be able to leave them connected. just make sure when you reconnect them at the rail make sure you can spin the ends into the block first then tighten down to make sure you don't cross thread them.

5. disconnect spark plug wires and remove the whole distributor. try to mark where the distributor is turned to because it will make it easier to adjust the timing when you put it back on.

6. disconnect coolant hoses in front of manifold i.e. radiator hose and heater core hose I am pretty sure. Might have to unplug some sensors too.

7. take valve covers off. might be a pain to get to the bolts with the egr and air tubes in the way but i am pretty sure there are 6, 10 mm bolts. I think you might need a deep socket too since some of them are studs. before you take them off you obviously have to take off breather tubes and stuff but that's pretty obvious.

8. then take off lower intake manifold. There are 10, 10mm bolts that hold it down.

9. loosen up rockers to get the intake manifold gasket out.

10. before installing new gaskets or what ever, make sure to scrape the old stuff off.

That is how you get to the manifold gasket if that's what really needs to be changed, not really sure on what you were asking

 

Thanks for your input, i was just asking general questions i had before i start getting to the gaskets. Im assuming depressurizing the fuel lines is nesesary for tackling this kind of project. How do you depressurize them?

 

There is a valve on the fuel rail where the lines go into the fuel rail. Just push it down until fuel stops squirting out