Originally Posted by kanecats
As it turns out...after several trips to various places (Advance, Pep Boys, Napa, Lowes, the Dealer) the diagram by GM is incorrect. There are in fact 3 bolts...4 attaching the pulley, and then two sizes which attach the water pump. Only one is reflected in the diagram, and those are of course not the bolts I need! The dealer recommended, of all places, Ace Hardware. The bolts are 5/16 #18 and 3" long. They are flanged Hex heads. Sure enough they had the exact bolt needed...so problem solved. It just took the better part of my day and process of elimination to figure it out. So $8.90 later I am a happy camper.
The existing bolts were extremely rusted and flared by the hex head. I wire brushed them, but I didn't feel safe in re-using the bolt. Another 100k later it would likely strip out in the block and then I have a real issue. For 9 bucks I have peace of mind! As a female this intake manifold change has been rather challenging, but doable with the correct tools.
Thank you for reaching out to give me a hand!!
Sorry about that, I was up way too long, and I had to open a couple of tabs to find the right one, I looked at and copied the wrong one, that'* my fault for having to many tabs open.
Here is the actual diagram I meant to look at, and post.
I did not know your pulley bolts were bad also, you did not mention them.
The water pump pulley bolts are displayed in both diagrams, as part #315, 24503961 BOLT. Early Fuel Evaporation Control. Fan and Coolant Pump.
BOLT,W/PMP PUL(M6X1.0 6G THD W/WA)(8MM SOCKET HD). Required: 04
Congratulations on getting the intake manifold job done, I recently learned to do my own, I was a little hesitant at first because I had only replaced brakes, starters, plugs, wires, and cv axles before doing it, but as you said, it was challenging, but with the right tools it was not too bad.