I am replacing the water pump on my 2002 3.8 Buick Park Ave and the lower long bolts are in pretty bad shape. Anyone know the replacement size and where to get them? I have been told several different sizes. I know they are 3" and hex bolt type. Not sure if they are metric or std or the size. Can anyone help me out on the gm parts # or oem alternatives? Tx!

There should be two different sizes of bolts, if you look at the bottom right diagram below you will see there are 4 x #336'* and 2 x #335'*, the bolts are going to run you around 40.00 plus shipping total, are you sure you cannot clean the old ones?
A friend "enslow" shared a good method for cleaning threads on the bolts, it is better than trying to use a chaser, you just find a nut with the same size/thread as the threaded hole on the block, then Make the O (O representing the nut head) into basically a C <--- the small channel you cut into one side of the nut will force the old gunk off the threads, and it is a lot more gentle on the threads than a thread chaser from what I understand, sorry right off I do not recall the specs of the bolts.
If my way of explaining making the thread cleaner does not make much sense I can get make a diagram/example of what I mean for you.
Here is the diagram I mentioned above.



http://parts.nalleygmc.com/showAssem...modelYear=2002

If you have not already bought the water pump I highly recommend this one, it is a little more pricey than the original one, but it should hold up longer, and it is also nice that it has an aluminum framed gasket, which I think will outlast the old paper design, not that I have heard of many leaking from the gasket before from the weep hole, still I like to put the best parts that I can on my PA.

Don't forget some of this to put on the bolt heads as you replace, or put the cleaned bolts back in.

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.


http://parts.nalleygmc.com/showAssem...roduct=2997515


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.

There'*

4 of the 13mm headed bolts that hold the pump and timing cover to the block
4 of the 8mm that hold the pulley on
Then there should be 4 10mm headed bolts that hold the water pump to timing cover. I recall there are three on top that are easy to see and one below in the center.