Upper air intake manifold

#1

2000 Chevy Malibu 3.1 automatic 112,000 miles. I had to replace the lower intake manifold gasket because of a coolant leak. While reassembling, using a torque wrench, tightening the upper air intake manifold bolts to 18 ft. lbs. the forward left ear cracked. The crack does not go all the way through the manifold. Is there anything that I can do besides replacing the manifold? All other bolts are torqued down to 18 lbs. Can it be welded? What did I do wrong???

#2

Do you know if there’s a tightening pattern for these bolts? I would bet that there is, and if you don’t follow the pattern (often completed in two steps), you risk warping or cracking the part. There is also the possibility that the piece was just old and cracked when tightened down.

I assume this is an aluminum piece, and yes, it can be welded, but there are a bajillion 3100 motors in junk yards and it might be cheaper / easier to go get one from a junked car.

#3

The 2000 year manifolds only have 6 bolts. The manual states that there is not bolt tightening sequence. Other sequences usually call for tightening from the middle to the ends. That is what I did. Yes, it is aluminum…

#4

Try jb weld