Engine Replacing Water Pump - Found Brown Sludge and Some Other Questions?

[TwinturboHoward]

Hello all, I'm replacing the water pump that's been on for about 20-25 years. Nothing's wrong with it, but I've been fighting an overheating issue for the past couple of years so I'm replacing it along with the radiator.

So when I removed it, I found a brown sludge in the material savers of the pump. I suppose that doesn't guarantee that it's also been circulating through the system, but I can't rule it out. What would cause this? - see pics.

For the installation, I can't find anywhere that tells me what to torque the 2 'thin hex' bolts that bolt the backing plate to the water pump at the bottom. I'm going to assume it's 13.5 ft/lbs - anyone know?

Also, for liquid sealant, I was going to put a small amount around the two water ports on the backing plate to timing cover and along the entire backing plate to water pump gasket. Is there a recommended brand everyone likes?

And lastly, the 4 outer long bolts - some kind of silicone sealant on the threads? just the heads?

Thanks everyone.

 

[General karthief]

I would flush the block, if possible knock out the two 'freeze' plugs on the sides (the ones at the rear) and flush with hot water, you can hook a garden hose to the hot side of a clothes washer hookup, spray into the holes in the sides too, be careful, that water should be 110° to 120° coming out of a water heater, I jacked up the car, filled it with hot water then knocked the back plugs out and flushed it somemore, a lot of crap came out, I slather up the water pump bolts with anti seize from the threads to the head, a skim coat of blue rtv on the gasket, just enough to keep it in place, wait a few minuites and slap it on. I snug the bolts crossing side to side for even pressure, i even let it setup over night but it's not necessary.

 

[TwinturboHoward]

Thanks for the reply, I don't think I'm going to be able to flush the block but, today I drained the block and, fortunately, nothing but clean green coolant flowed out - no sludge. I should have also mentioned that the coolant passages to the water pump were clean as well. In this pic, I only cleaned up the gasket surfaces.

Thanks for the info on the sealant too. That's what I'm going to do.

 

[General karthief]

Yea, your good to go