How to Replace the Water Pump in a Cadillac Northstar 4.6 liter
I'm just going to give you a rough idea how to complete this. Don't assume the following steps are all that is needed. I'm recalling this from memory and may have forgotten a step or two. The most confusing part is putting the pump back in. If you have a Haynes or GM service book, it will help you get the part off, but they are useless for installing the new pump. That's the reason why I'm writing this. You'll need a water pump removal tool. Lisle makes one that worked for me. The part number is 14440.
1. Remove the air cleaner housing and plastic shield on top of the radiator.
2. Put a piece of plastic over the anti-lock brake controller. This is directly below the lower radiator hose and it will get a thorough drenching if you don't protect it. I don't know if could be damaged with a flood of coolant, but it can't hurt to keep it dry. I just used a kitchen sized garbage can liner.
3. Remove the lower radiator hose and drain the coolant.
4. Remove the 4 bolts that hold the water pump cover on. The lower right bolt is the toughest to get a wrench on.
5. Put the water pump tool on and turn it clockwise to disengage it from the tangs in the housing.
6. Clean the gasket mating surface thoroughly. Don't scape at the surfaces with anything that might damage them and cause a leak. All I did was clean them with lacquer thinner.
7. Remove and replace the two rubber/silicone o-rings. Install the cover gasket dry, in other words, don't use silicone grease on it or it won't stay in the cover. Use a little silicone grease on the o-ring that goes in the housing. This keeps it in place until you install the pump.
8. Install the pump by positioning the indexing ear in the one o'clock position. It will not go in any other way. The GM manual doesn't tell you this and the Haynes manual says to put it in the 7 o'clock position. Neither of those books were of any help and the Haynes was actually more trouble than it was worth. ARRGGGHH!!! Put the tool on the pump. Wiggle it around to make sure it's seated onto the pump properly and turn it clockwise to 73 foot pounds.