2004 V8 TB EXT Coolant Leak

[MoJoRisin']

Hey guys - got home from being out of town and was told the TB decided to empty out alot of coolant in the driveway. Radiator was down over 1/2 gal, overflow reservoir is empty. Topped off the radiator with 1/2 gal water then some antifreeze and then saw pretty good dripping from bottom of water pump (not running). Only could look from above. This happened when the wife was taking the boy to and from school and only was driving a short distance. No report of hot light coming on or steam under the hood so I dont think we had an overheat condition.

TB has over 105k on it.

Tried to move fan around to see of water pump bearing was shot and did not notice any play.

What is proper troubleshooting here to locate problem and only repair what is required?

Plan for now is to remove shroud, belt, and then try again to move fan and clutch assy checking for excessive play.

It is possible we may have been having a slow leak that got bigger. I had been noticing some small fluid thinking it was A/C condensation.

Also see reports of specific torque recommendations for water pump - please advise torque specs and if loctite needs to be used or not. Also should gaskets be used as is or add RTV?

Thanks much in advance for input!!

 

[Playsinsnow]

I've replaced the water pump twice now. First time was noisy, second time was a leak. Water pump comes with a gasket. Just alternate tightening the bolts holding the pump to the block to ensure all are tightened evenly/properly.

Remove the belt and spin the waterpump pulley. Is it smooth?

No loctite for me. Remove the pulley and you'll have a better view.

FWIW, when my RADIATOR began leaking, it would only leak when motor was cold.

 

[jimmyjam]

I've replaced the water pump twice now.

OP has a V8, different water pump configuration

I had a pump start leaking, didn't notice any play in the pulley/shaft, however the coolant was coming out of the shaft seal. hard to tell since the pulley is basically over the shaft seal area. you might be able to stick your finger on the bottom of the pulley on the inside to see if coolant is collecting there, if it is, then it is most likely the shaft seal.

If this is the case, you're best bet is getting a new pump. I tried taking a pump apart to paint it and getting the pulley off is difficult if not impossible, they didn't design them to be easily rebuilt.

Auto part stores sell the appropriate gaskets. they are the same amongst all 1999-present chevy V8s. a new pump will probably come with gaskets

per the tech manual
On the initial pass, tighten the bolts to 15 Nm (11 ft. lbs.) .
On the final pass, tighten the bolts to 30 Nm (22 ft. lbs.) .

 

[MoJoRisin']

OK water pump changed - leaks gone. Was the large o ring around the impeller housing - definately has been leaking for some time and finally let loose.

What is the proper torque spec for the tensioner pulley brackets 3 bolts? also tensioner pully single bolt torque?

Thanks for the info guys!!

 

[jimmyjam]

for the 3 bolts
Tighten the bolts to 50 Nm (37 ft. lbs.) .

as far as your 2nd question, not sure what you're talking about. the pulley on the tensioner? shouldn't be messing with that. if you're talking about the idler pulley, that is also 37ft#s

 

[MoJoRisin']

OK Boys - one of the thermostat bolts decided to loosen up and got a trickle going. According to the Haynes manual torque is 132 in lbs (or 11 ft lbs). Can someone please verify this torque is correct? Also this time around there will be loctite.

On the other question that I had - when changing out the water pump, the bracket for the tensioner pully needed to be removed. Those 3 bolts are the torque I was asking about - and the tensioner pully as I had removed the pully to get to various hoses attached to the water pump. The tensioner pully is a PIA as when you tighten it it pivots.

THANKS GUYS!!

 

[jimmyjam]

1. Install the thermostat housing bolts.

• 
  Tighten the bolts to 15 Nm (11 ft. lbs.) .

Don't know why you removed the pulley from the tensioner bracket. if you need to get the pulley out of the way, remove the bracket. i never touch the pulley, if there is a problem with it, get a new tensioner assembly.