hello I have a lq 408 motor. I had been having some trouble with my clutch chattering.i had the passenger head off for something unrelated. I cleaned the block and head well. I cleaned out the block head stud holes so there was no fluid and junk on the threads. put it back together and drove around a few miles and the clutch was chattering like crazy so I parked it in the garage.

I ended up finding a ton of bolts in the bellhousing and transmission loose. I tightened them up and that fixed the chattering issues and the car was running good but i noticed if the car sat for a day or two there would be a quarter size amount of coolant under the car coming from the last bottom head studd in the passenger side. I pulled the head off and I found this whole in the block. can this be welded? it seemed like it was leaking from the headgasket area, otherwise where could the coolant be coming from?

 

Not sure what "whole" you mean. I see a water jacket, and a head bolt hole that should also have a dowel pin, but doesn't. Aside from the missing dowel, everything looks normal. I don't see anything that it would make any sense to weld.

 

This.

Also, why the hell were all those bolts loose?? You got lucky on that. If all those were loose, I would check the flywheel bolts too. Yikes...

 

The missing block dowel is there for a reason. Primarily, it properly locates the head on the block. It also properly locates the head gasket. Without the block dowel, the head and the gasket were misaligned, and that's most likely the reason for the water leak.

Properly torqued bellhousing bolts don't just come loose in just a few miles. What did you use to torque them down with?