2006 Envoy Denali Water Pump 2 questions

[Jkb242]

I’ve have done this repair on a couple of 4.2L early 2000’s but not on this model.

I had a coolant leak and thought it was the thermostat so I purchased a new thermostat and housing. After installing the new thermostat and housing, I did a run test to operating temp and confirmed no leaks. This morning in preparing to purge any air from the system, I was topping off the radiator then noticed a pretty large leak. Obviously I misdiagnosed the source of the leak. The new Gates water pump comes with a thermostat housing gasket (but not the housing or thermostat) so not having any leaks from the new thermostat with no housing gasket, I’m wondering if adding the housing gasket on the new pump might prevent the rubber ring on the thermostat from seating properly. Should I use the housing gasket that is supplied with the water pump or not?

Question 2 are the these torque specs correct?:
Water pump 11 ft.lbs first pass then 22ft.lbs second pass, alternating bolt pattern.
Idler 37 ft.lbs
Any sealer recommended, possibly to keep the gaskets in place even with studs inserted?

The Car doctor YouTube channel has a great video on the 5.3L, originally post here by another member.

 

[flyboy2610]

When I replaced the thermostat on my '04 TB 4.2 I used the rubber O ring. No other gasket.
If the thermostat is working properly with no leaks, I wouldn't worry about using the Gates gasket. Keep it for a spare.

 

[Jkb242]

Thanks. That’s what I was thinking. This was the first time I change the water pump on the 5.3L, just didn’t expect to find no gasket or O ring on the thermostat housing. Apparently the rubber molding around the drop-in thermostat for this application is sufficient as there were no leaks on the one I thought was leaking or the new one after installing and up to operating temp.

 

[Jkb242]

When I replaced the thermostat on my '04 TB 4.2 I used the rubber O ring. No other gasket.
If the thermostat is working properly with no leaks, I wouldn't worry about using the Gates gasket. Keep it for a spare.

One other question in prepping for the new water pump install, is there any reason why a few drops of 3 in 1 light weight oil to the hose end at the metal nipple would be an issue? This really helps to break the hose loose from the fitting easing the hose removal? I don’t have any channel lock pliers that don’t have teeth to use to prevent damaging the hose end. I use a rag between the jaws of the channel locks to prevent damage but without a few drops of the 3 in1, the gripping pressure required is quite worrisome. The hoses are in excellent condition and may have been replaced before I purchased the truck but are the GM original design with the captive clamp molded at one point on the hose. The upper and lower are the same original GM design. Thanks!

 

[mrrsm]

Petroleum Distallates (ordinarily present in high concentrations in 3 &1 Oil) can break down Rubber and might make for a loss of ID material of the Radiator Hose over time. Instead, using a Very Slight Smear of some Lithium Grease would do the trick just as well, as long as the Spring Steel Hose Clamps are in their right placements.

 

[Jkb242]

I have some which I used for brake jobs in the past guess that would work. That really doesn’t help in removing the hose where hose replacement isn’t required. I need something liquid or is there a tool to separate the hose from the metal nipple like a pick?

 

[Jkb242]

Petroleum Distallates (ordinarily present in high concentrations in 3 &1 Oil) can break down Rubber and might make for a loss of ID material of the Radiator Hose over time. Instead, using a Very Slight Smear of some Lithium Grease would do the trick just as well, as long as the Spring Steel Hose Clamps are in their right placements.

What about an organic liquid like olive oil?

 

[mrrsm]

Any chance you can unbolt the Thermostat Housing first... and then work on coaxing and removing the item from the hose afterwards?

 

[Jkb242]

That could be an option but I was attempting to minimize coolant loss. The most difficult part was removal of the heater hoses from the thermostat giving the limited length extending from the captive formerd hose assembly leading to the heater.