I want to remove the entire TPI intake manifold. I did a pre-Search and learned that I should remove the runners and fuel rails for clearance first and that is clearly understood.

Question: what star bits do I need? A trial fitting for the intake seems to be T-45 but a T-47 seems to be ideally snug however a certain few bolts feels frozen and I noticed I will strip them if I went further without asking the pro's here.

I will begin by soaking the bolts with PB blaster penetrant and wait for some replies. Also taking pics for show & tell soon.

Reason for intake removal: Rear most theromstat housing bolt is stripped and I ground it down so I can remove it by an EZ- Out but it's being very problematic now I thought about removing the intake manifold entirely.

More Questions:
1- I assume the distributor will be the last to remove?
2- Car has been sitting for a month, fuel pressure must be low to zilch?

 

u can just take off the throttle body(4 bolts) and get at the thermostat bolt. if thats the only reason to take it all off. taking all of the intake off is a pain in the ***. but i guess if u plan on taking the actual manifold off, then ide buy a haynes manual. and abviously use the bit that fits tighter...and hope it doesnt strip out. i dont understand what gm was thinking with those damn torx bits.

 

The runner bolts are all T40. The Intake bolts are T-45.

 

I stripped almost all of my tork heads removing the intake from my doner car. Used a chisel bit in an air hammer to encourage them to rotate. Having eng out of car was a great advantage.

After you get them out, take them to a good hardware store and get some high quality allen heads bolts to replace them. Then use a long T-handled ball-end allen wrench. It makes doing the job much easier. Don't use bolts that are longer then original. They will bottom out just as the gasket starts to compress creating a vacuum leak that "can't be fixed" (guess how I know that).

BTW, I've started using anti-sieze on just abt everything, especially things with alum threads. Makes for a lot less headaches down the road.

 

I didn't strip any of the intake bolts, but I did break 2 torx bits getting them out. Invest in some heat treated/tempered torx bits to avoid this. I also replaced mine with 3/8" allen bolts. They look better, and a standard 3/8" GM brake caliper socket fits them. I also put RTV on the threads of all of them, to prevent them from seizing.