2006 GMC Savanna bad water pump

[cabledawg]

OK, back story is that the pump was leaking but not bad. I just kept on top of the coolant and maybe added a gallon every month or so. Fast forward to last night and I see a huge pool of antifreeze under the front and knew the pump finally gave out. Sure enough, got the old one out and I could see where it had been leaking from a casting joint under the thermostat.

Buy a new pump and thermostat, get it all installed and the engine now overheats, the heater doesnt work and it seems like the pump isnt even moving coolant. I changed out the thermostat for the old one thinking maybe the new one wasnt the right part and same thing. I've checked the coolant and its topped off, but when the engine is running hot,the hoses are all cold. So is it possible that the new pump is bad from the start? I'm pretty sure the belt got put on the right way, but even backwards, wouldnt the pump do something?

Frustrated as I now have three vehicles and all are out of commission.

 

[Deuling]

Could it be the wrong pump? Like a reverse pump on a non reverse setup? Or vise versa? Or wrong belt routing somehow?

 

[cabledawg]

Well I fixed the problem. On my Subs, the lower rad hose goes to the pump and the upper goes to the thermostat housing atop the engine block. When you install a new pump (or whenever the system is drained) you simply add coolant to the radiator and it funnels right to the pump, circulates and eventually fills the system.

Not so on the new 6.0l engines. The lower rad hose goes to the thermostat housing and the upper to the pump. If you fill up the radiator, it never gets to the pump because of the thermostat and hot air in the pump isnt enough to open the 'stat. So after scratching my head, I thought I'd try filling from the upper rad hose. Sure as ****, it took another 2.5 gallons, heat started working, coolant was moving through the rad and the temp stayed below 210 deg.

****ing GM...................

 

[4xcrazy]

Interesting, I just filled the expansion tank on the fender well, since there isn't an opening in the radiator, everything filled up right, unless the 5.3 and 6.0 are totally different, which I could have swore they weren't too far off.

 

[cabledawg]

Yeah, my expansion tank connects right under the radiator fill cap, but wouldnt drain into the radiator until the pressure relief valve was opened.

It might be a van thing too, who knows. Just like I found out there isnt a radiator drain valve. My Chiltons actually states that to drain the rad, you simply disconnect the lower hose Seems kinda messy (and it is) and impractical since the stock clamps would be near impossible to release without removing the fan shroud. I replaced mine with a traditional screw type clamp so its now easier to loosen/remove and all I have to do is take off the expansion tank.

 

[4xcrazy]

Application specific apparently, ours doesn't have a drain valve, no fill cap on the radiator either.

 

[Larry]

That is a drag. What is more of a drag is many people end up replacing the water pumps on this generation of engines when only the water pump to block gaskets leak. When the gaskets leak you cannot see in there real well to know for sure where the leak is coming from so most people shotgun a water pump on the vehicle. I work in the truck manufacturing industry where we use 4.8, 6.0 and 8.1L engines in the trucks we build for RV’s and commercial delivery vans and can’t tell you how many times dealers have thrown on a $300 water pump on an LS engine over two failed $8 gaskets. I have never heard of a leak from a cast especially on an engine that already has some miles on it but anything is possible I suppose.

Dealers use a procedure called vacuum fill where they draw a vacuum through the expansion tank to suck the coolant in from the radiator drain or lower radiator hose adapter in order completely fill the engine without the air pockets. Definitely a must have tool for late model diesels or a bubble will form in the EGR cooler costing a several thousand dollar repair. New vehicles are a PITA to work on!

 

[KaMi]

http://www.nationaltoolwarehouse.com/Airlift-Coolant-Refill-Kit-P39625.aspx

my buddy has this, very handy. creates a vacuum(not sure how good that is one the hoses) then you open the valve with one end of the hose in a bucket of coolant/water and it will suck up the coolant and fill it right up to the top of the rad, then you pour the rest into your overflow. makes quick easy work. Also you will find out super fast if you have a small leak somewhere as it won't hold a vacuum