2004 Sierra 1500 5.3L Coolant Leak Options

[jmassi]

Ok guys, here's what I got. My dad has a 2004 Sierra 1500 4x4 5.3L w/40K miles on it. He noticed coolant leaking so he went to his buddy who is a mechanic and the two of them looked for over an hour and could not find where the leak is coming from. They did a pressure test, and it slowly lost pressure. Everything under the hood, engine, hoses, lines, water pump, engine block, radiator, all are bone dry. The only thing that's wet is a wire loom thats underneath the front of the engine where the harmonic balancer is. This wire loom is for the four wheel drive (which works perfectly). My dad's buudy has been a mechanic for over 40 years and my dad has been working on cars for the same amount of time and both of them are stumped (so am I!). Any ideas as to where this leak could be coming from? Any input would be greatly appreciated.
Thanks!!

[bigred91]

intake manifold gaskets are nitorious on those things

[Norseman]

intake manifold gaskets are nitorious on those things

Nope, can not be intake manifold related. It is the water pump gaskets. Use the metal Fel-Pro gasket to fix your problem.

[Mr. Smith]

intake manifold gaskets are nitorious on those things

I guess that would be an issue IF coolant went through the intake.

[jmassi]

intake manifold gaskets are nitorious on those things

Nope, can not be intake manifold related. It is the water pump gaskets. Use the metal Fel-Pro gasket to fix your problem.

Norseman, you were right. My dad went to his mechanic buddy and once they tore into it, they found out that it was the water pump gaskets. He replaced them and all is well.

[Norseman]

intake manifold gaskets are nitorious on those things

Nope, can not be intake manifold related. It is the water pump gaskets. Use the metal Fel-Pro gasket to fix your problem.

Norseman, you were right. My dad went to his mechanic buddy and once they tore into it, they found out that it was the water pump gaskets. He replaced them and all is well.

Thanks for the up date! Yep, 99% of the time if you have a coolant leak on these 5.3L, 6.0L, etc. it is gonna be the water pump gasket (or at least that's where I always start looking), and the fix is the metal Fel-Pro gasket.

[99xjsport06]

Interesting....been trying to track down a coolant leak that also shows no symptoms on my step dads 04 with the 5.3. I'll definitely look into the WP gasket.....how hard is it to change on the 5.3? I don't have any repair manuals for this thing....looks like i'll have to invest in an el cheapo Haynes or Chiltons untill I can come up with a FSM for it.

[Norseman]

Interesting....been trying to track down a coolant leak that also shows no symptoms on my step dads 04 with the 5.3.  I'll definitely look into the WP gasket.....how hard is it to change on the 5.3?  I don't have any repair manuals for this thing....looks like i'll have to invest in an el cheapo Haynes or Chiltons untill I can come up with a FSM for it.

Not hard at all. Couple of hours. Remove drive belt, don't bother takin' the fan off just unbolt (6 bolts, 3 each side) the pump clean surfaces of pump and block (I use paint thinner). Then put the new metal Fel-Pro WP gaskets on the pump held in place with the bolts, and bolt to the block to proper torque. Put belt back on, top off coolant and job is done. Easy!

[C & A s Dad]

Norseman, I am just curious. If the truck had say 50K on it would you not recommend going ahead and replacing the pump while you had it off?

It would seem to me that it would simply make sense to replace it since you had gone this far. Of course, I am in the Auto Parts business, so I would naturally recommend this. LOL

Just wondered how you felt about this.

[Norseman]

Norseman, I am just curious. If the truck had say 50K on it would you not recommend going ahead and replacing the pump while you had it off?

It would seem to me that it would simply make sense to replace it since you had gone this far. Of course, I am in the Auto Parts business, so I would naturally recommend this. LOL 

Just wondered how you felt about this.

Sure, If you feel like spending the extra money for a new pump. Lets see, I've helped my friend on the weekends at his shop when he gets backed up from the previous week for a while now, I've done around 6 of these now just replacing the gaskets and none have come back. Those pumps are really hardy and the job is so easy if you're gonna do it yourself why not just replace water pump when it really wears out? If the job involved removing a timing belt cover to get to the pump like a lot of JapJobs require then I'd say sure definitely change it while you're in there, but that's not the case so why waste the money?

Not trying to take business away from you, just tryin to save some one a few bucks