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1997 deville northstar coolant leak

19K views 16 replies 7 participants last post by  s281er238 
#1 ·
hey guys, i wish to thank you for your assistance up front.
situation, yesterday, i was driving caddy, pulled into store, got out of car and engine smoking, open hood, coolant leak from front right side of engine under water pump area. took home immediately and parked. this morning, put it up on stands and try to trace, just a little coolant was leaking directly under water pump area. thought maybe a hose, not. pulled everything apart, read manuals. possible water pump housing leak, My question (s) 1. does the northstar have a weaping valve or hole like other gm models, so if leaking means water pump bad?
2. if not, does seal gasket just give way and leak on a regular basis
3. a duh, question, should i just go ahead and replace the water pump and the gasket for the water pump housing?
have not pulled codes, since it was kind of obvious, no over heating.
i checked 3 places for the gasket and no one has, do you think rock auto will have?
thanks for the help
 
#2 · (Edited)
There are two gaskets in the immediate area of the water pump. An O ring between the pump order and the coolant crossover (pump pulley side), and the water pump cover gasket. The pump shaft seal, and hoses in that area would be the other culprits.

There would be no reason to replace the pump unless the pump shaft seal is leaking, or the bearing has failed. The impeller is steel and doesn't wear or crack over time like a plastic one would.

If it ends up being just a hose or gasket, just go to a local dealer parts department.
 
#3 ·
ok, i need you to explain a little more. i know about the seal in the water pump cover, looked at rock auto, and they have for 3 bucks. where is the o ring between the pump and the ?, is the coolant crossover the housing that houses the actual water pump? and where is the eater pump cover gasket?
 
#6 ·
so to replace the O ring at the crossover and the water pump, i am going to have to pull the water pump itself? correct? the water pump crossover is part number 321 and the pump is actually 312 according to diagram. I love pictures, learn better that way. the remainder i think is easy now and can do......

2nd question i was going to go ahead and replace the water pump belt, but that one seems to be tricky, i pulled off the belt from the tensioner and the water pump pulley, but how do i get the belt off to replace?

thanks cabbage and ranger, you guys are definitely the knowledge pros
 
#7 ·
Yes, to replace the O ring you will have to remove the pump. It requires a special socket, which you can rent from most any parts store (try to find a quality, thick, cast socket, not the cheap thin stamped ones). Pay attention to the position of the one odd tang on the pump during removal, clock it in the same position during reassembly. Apply pure coolant to the new O ring before installing.

The pump drive belt just has to be snaked around the pump, drive and tentioner pulleys. You do have the black belt shield/shroud removed, right?

Check the tentioner pulley while the belt is off. It should not feel notch or "gritty" when turned. It should turn smoothly with the slightest amount of resistance, if it spins and spins very freely/loosely, it is a sign that the grease has dried up. The pulley can be replaced, or repacked with grease (if not already worn). Make sure that the belt is properly seated in all of the pulley grooves when reinstalling. Proper coolant is a 50/50% mix of DEX COOL and distilled water.
 
#8 ·
Water pump, cover and water pump drive tensioner pulley.

The water pump capsule unlocks with a tremendous amount of force, clockwise 1/5 turn. Remember the location of the small locking tang. The new pump (wet the O-ring with pure coolant) goes in with 73 ft/lb of torque counter-clockwise.
 
#9 ·
ok guys, well today was interesting. i found all parts except the O ring, i thought well maybe it is just the seal to the water pump housing, NOT.....filled up with antifreeze and still leaks.....however, i saw where....it is coming directly from the back of the crosshousing....so is this definitely the O ring, or does the cross housing have a gasket also.....????
next question....can you buy the O ring by itself, i was unable to find by itself? thanks guys
 
#10 ·
If it is leaking from the O ring, the leak will be dripping from behind and below the WP pulley. If it is the crossover gaskets it will be leaking from where the crossover manifold meets the block. That is not an easy job.

Any dealer would have the O ring.
 
#14 ·
So i think i have a leak on the crossover manifold in my 97 deville...i seen it leaking thinking it was the water pump so i go and buy the pump and the gasket put it in thought i was all good. So i took a ride and sure enough its still leaking. I cant exactly see where its coming from but im guessing its the xover gaskets...how hard is it to do? it doesnt look that hard except for all the different star heads and hex bolts everywhere.....and when i do it should i also use that rtp silcone for extra strength? any help would be appreciated...i hate seein my baby leak..shes pearl white with the chrome rims and shes sittin cuz im not drivin it like it is:(
 
#15 ·
4 gaskets, 8 bolts, some of them in a tight space. You need to basically remove everything that gets in the way. I don't think there are torx screws involved.

It's a time consuming work dealing with bolts that are hard to get to. Putting it back with gaskets and bolts in correct places is worse, but a member once suggested using rubber bands on the bolts to make them stay better with gaskets, decreasing the chance of sliding and falling.

 
#16 ·
The gaskets go on dry, NO sealant of any kind. Get yourself a 13 mm flex head, ratcheting wrench, it's worth it's weight on gold for this job.

Is it hard?: like maeng said, keeping all 8 bolts and all 4 gaskets in place while reinstalling the crossover is a huge PITA. There is a large under hood harness that goes over the transmission that is going to be in your way constantly. Unbolting it's grounds will give you a little extra wiggle room.

Make absolute certain it's the crossover gaskets that are leaking before you dive into this repair. Also, make sure you have another vehicle available if you'll need one. The job took me a bit over 6 hours, but split over 2 days. You'll most likely want to take a break half way through.
 
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