Best way to remove a snapped intake manifold bolt?
 

Taking the intake manifold off and on a few times I got lazy and decided to re use the old bolts on the last time doing the 82mm throttle bodies.I now have 2 snapped bolts sticking out of the block.

I don't think it was from the old bolts. I think it was from the spacers I did and the bolts were over torqued.

any tips on how to remove these?

1)Drill and tap with a left handed thread set then screw in a left handed allen screw, go very slow because you will be eliminating the wall thickness of the bolt you are trying to remove.
2)You can dremmel a line on the screw then use a flat head on a ratchet.
3)Just drill into the bolt and reverse the direction and hope you get lucky it grabs. Do this last.

Either way keep the vacuum nearby and good luck.

I over-torqued and snapped one of mine when I was replacing the IM gaskets. I just used a the smallest bit from a cheap screw extractor set (similar to the one linked below). With the uneven surface on the top of the broken bolt, I drilled a tiny pilot hole for the extractor bit to get a good bite. The bolt will come out easily as there is very little torque applied to them.

Screw extractor set

That's the route I was heading. It's going to be tough because these are stretch bolts and thth are now not turning through the groves .

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I'll give it a shot. Did you do it on a cold engine or hot? Trying to see if I should let her get hot then try as she cools off.

Soak with some penetrating oil and grab a can of keyboard cleaner to spray the bolt with before you start torqueing.

How far are they sticking out?

They are sticking out a good amount.

It shouldn't be tight, there's no load. Can't you take them out by hand?

Vice grips was my first attempt ,the bolt stretched off the threads.its like welded in place even with the manifold off.

I didn't strip the bolt,it actually twisted the screw and half came off with the wrench.

It will be my weekend project and will try everything you guys mentioned.

I ran the car for months Ike this ( 2 broken bolts) but it's just driving me nuts knowing 2 are not holding it down

Yeah, this was a key piece of data you neglected to mention earlier. This seems common with a few of your posts BTW.

You're dealing with corrosion between 2 different materials. It's a galvanic reaction or something like that, someone way smarter than me can confirm.

You can probably soak it with liquid wrench and use heat to extract once you can clamp something onto the protruding stud.

Maybe you miss understood. It's been months since I've tried everything to get the bolts out. The bolts were jammed in there from day 1. I put the manifold back on to warm the car up and took it off a few times trying to get them loose without drilling them.

Car is all together now for a few months running fine.no leaks or bouncing idle etc.

its not corrosion it's a stretched bolt that is not lining up in the threads to come loose.

Hold off on using heat.
Just to clarify:
The manifold is magnesium alloy, the bolts are aluminum, the heads are aluminum.
These bolts go through magnesium with a passing bore and thread into aluminum.
The magnesium alloy expands by an unusually large amount, I think I recall more than Aluminum, so it was necessary to use Al bolts, because with steel bolts the manifold would crack as soon as it expands.

So if the manifold is still on, I would not heat anything because it will probably snug the manifold around the bolt.
If the manifold is off, it's not like a steel bolt into an aluminum head, heat the head, it expands more than the bolt and now the steel bolt is loose, I don't think you'll have an advantage heating anything.

Heat expands , cold contracts. Its going to be much easier to cool the bolt (shrink it - low density ) vs heating the head around the bolt (expanding - high density). With heat the aluminum bolt will absorb that heat very well just making it tighter. Cooling the bolt may work better because the bolt will absorb the cold much more quickly and more efficiently than the higher density head, allowing you to break it free. Just my 2 cents.

This is fairly easy to remove! Best way is to drill a hole with a smal drill bit and then simply use a torx bit, find a size that will fit and give it a few taps with a hammer until its snugg tightly. then just it will twist of with a drill or watever type or torx style bit you put on the broken bolt. This works even when the bolt is really tight because the torx grips/bites into the metal.
https://cimg8.ibsrv.net/gimg/www.mbw...622a888e7.jpeg
Picture for Reference

That bolt shown above is steel. Because the intake manifold bolts are Torque To Yield the aluminum is very soft and may strip. What ever method you try, go very slow, you will only have so many attempts before that part of the bolt is destroyed.