I was ready to drain my cooling system for the last time and fill it with fresh coolant. While waiting for the motor to cool down I realized that I have a slight water leak. I noticed it earlier and thought it was fuel but I was wrong. The top of the water pump housing between two upper bolts is wet. Very minor leak from gasket failure I guess.
My questions are:
1-Do I do just gasket which I have already or should I replace the pump too? New pump is $30, not a big expense.
2-Is fan clutch required to be replaced when replacing water pump? On Chevy trucks the book says replace the clutch every time you do the pump. Here is another $140 or so..
3-Whats the deal with two upper bolts holding the pump?
4-Do I need thread sealant on the bolts.
Sorry for too many questions. Thanks.

 

1. Yes
2. No.
3. They may be shorter, only sticking out of the back of the water pump and into the plate behind by 1/4". A lot of newer water pumps seem to come with a modified casting that allows for using the same length of bolt; the casting 'boss' is deeper than the original design was.
The problem is if the bolts extend too far through the engine front cover, it will hit the cam gear behind it, and break something.

4. Middle two on both the top and bottom should have sealant. The rest don't matter. I always use RTV on the water pump gasket sealing areas.
If you don't use the sealant on the threads of those bolts, you can get a very slow leak of oil migrating out through the threads. Just a few drops.

 

I found an old thread on this forum from 9/16/11 titled "water pump?". I can't post the link as I'm on unfamiliar F%^*}# smart device right now.
Here is the quote from post #5 in that thread:
"hold on before you replace the water pump when you buy the new one make sure they give you two bolts that go in the very top of the water pump because the original bolts will shear your injector pump"
No mention about modified casting, just the statement that original bolts will shear ip.
Can you elaborate on this please?

 

I've seen that post, and was careful at first.
Like I said, verify the length of the bolt sticking out of the back of the water pump on those middle two, upper and lower.

Last couple of water pump replacements with AutoZone pumps, I found that the casting seems to take this into account, because the bolts are all the same length... but the upper and lower middle bolts stick out of the back less.
I also found that with each replacement water pump, a couple of bolts were included. I'm guessing to account of people with original-design water pumps that have bolts that are now too short?


In addition, I ran into a reference on the improvements made to the design of the 6.9 over the years, and one of the items listed was a modified water pump casting to avoid the long bolt problem.
I can't find it to show you, though.

Simplest solution overall is to just pull one of the bolts from the upper middle, and one from the side and compare them. If they are the same length, well, you don't need to worry. If they are different lengths, keep them segregated. Also, your water pump should come with a diagram and instruction sheet explaining how the bolts are supposed to go in.

 

Thank you for the info Macrobb. Will go see tomorrow what is available locally.