Torque specs for fan/clutch/water pump

Thank you for*good*communication.

trailballer said:

water pump to block -------89 lb/IN<---take note of the IN thats inch not foot very very low!!!

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do you have to tighten water pump down in a certain order or no?

No certain order. There are 5 bolts. Just start by hand so no crossthreading.

I'd hand tighten then torque using a star pattern like your lug nuts on tire.

Great info. I was just wondering the same myself.

Torque for clutch nut...

Just to add FYI, the generalized instructions that came with my radiator fan clutch (HAYDEN 3200 Electronic - Viscous EV Fan Clutch Operation, ~$123) specified 37-45 ft-lbs for the clutch nut on the water pump shaft.

Although, I have yet to figure out how measure this when tightening the fan clutch nut during reassembly....is there a special technique or tool--I am only familiar with torque wrenches which use sockets. :-/

A trustful mechanic told me it'll tighten itself on, so to just bump it a few times with the special pneumatic tool he let me borrow. https://www.amazon.com/Lisle-LI43300-Pneumatic-Clutch-Wrench/dp/B000JFJLTC

FYI I just installed a new fan clutch, water pump, thermostat, and hoses. Now it gets up to temp quick without the jet engine startup. Took seconds to get the fan clutch off and forever to get the fan shroud on/off.

A trustful mechanic told me it'll tighten itself on

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That's what I thought, but the instructions claimed "Proper torque is critical to avoid the fan clutch from detaching from the water pump when the engine is turned off.", so I just did the best I could by hand with a thin (cone/ tappet) wrench.

just bump it a few times with the special pneumatic tool he let me borrow

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I bought that exact set for the removal process...worked great in the tight quarters...best to leave the serpentine belt on, though. :bonk: I didn't think to use it for the installation. I'll go back and do that, thank you!

Thanks for the torque numbers. I changed my water pump today at 140K (no leaks yet but the drain on the WP was grubby) and it was good getting those numbers. You are right - the 89 In lbs is very little and it is tempting to over tighten - and no leaks either!
I had a b!tch of a time getting the fan clutch spun back on the new water pump and did a bit of cross threading! Fortunately I didn't have it too far on and was able to clean up the threads on the fan clutch with my dremel and with a bit of fussing, was able to get it aligned and threaded back on successfully. I used the old wp to help clean up the threads on the fan clutch. Again as suggested above - this is something that should be gently hand installed so you know the threads are correct before tightening it up. My Envoy is a 2009 with no electric fan clutch - it seems to be only a thermal type. Was still a bugger getting all that stuff off though.

Broke off a bolt on my 2006 4x4 4.2 inline 6 Chevy Trailblazer. Finally able to drill out the bolt but the drill bit was slightly off center so it removed the threads on one side of the hole. After cleaning things up and retapping for the bolt, installed the new water pump but could not get the bolt to tighten. What is the maximum that the bolt hole can be enlarged to. Thought of retapping for a 1/4" sae bolt or going for a 7mm-1.0 bolt. Which makes the best sense?

jimbo7 said:

A trustful mechanic told me it'll tighten itself on, so to just bump it a few times with the special pneumatic tool he let me borrow. https://www.amazon.com/Lisle-LI43300-Pneumatic-Clutch-Wrench/dp/B000JFJLTC

FYI I just installed a new fan clutch, water pump, thermostat, and hoses. Now it gets up to temp quick without the jet engine startup. Took seconds to get the fan clutch off and forever to get the fan shroud on/off.

Click to expand...

I never even tighten the fan clutch nut. as it will seek it's own tightness and even if it's not whatever torque some engineer says it needs to be - it won't fall off ... believe me here --- it's success speaking --- 55+ years of success.

Once I have the fan nut on a few threads, I just start the engine. The reaction of the stationary fan-v-water pump shaft (spinning with the engine) will make it sufficiently tight.